DT-10 TIME ELEMENT RELAYS

VUABCCJ An American-Standard Company DT-10 TIME ELEMENT RELAYS SERVICE MANUAL 2366 This revised service specification supersedes all earlier editions and supplements of Service Specification 2365. Information is provided for repair and adjustment of DT-10 time element relays. The first 14 sections cover adjustments of relays of the latest design, including the multiple front control contacts. When adjustments given do not apply to earlier relays, the instructions for their handling are given in Section XV covering "Changes in Design Details". This Section also contains information and references for parts needed to revise earlier relays to the later design construction. SECTION I II m IV VI v VII vm April, 1979 B-79-250-390-2 TABLE OF CONTENTS Field Adjustment and Tests.... (A). Field Adjustment.... (B). Field Tests.... Neutral Armature.... PAGE (A). Armature Bracket & Pivot Screws....... 3 (B). Armature Air Gap.................. 4 Hold-Down Cores & Pole Pieces.... Clutch...,.., (A). Clutch Armature.... (B). Clutch (Brake) Wheel..... (C). Clutch (Knife Edge) Studs.... Shafts and Bearings..................... 5 (A). Oiling.......................... 5 (B). Drive Shaft Bearings................ 6 Oscillating Armature.... 6 Gear Train.... 6 Contact Adjustment...................... 6 (A). General......................... 6 (B). Neutral Contacts................... 8 (C). Neutral Control Contacts............. 8 UNION SWITCH & SIGNAL DIVISION WESTINGHOUSE AIR BRAKE COMPANY Swissvale, PA 15218 3 3 3 3 4 4 4 5 5

WABCCI SECTION IX x XI TABLE OF CONTENTS (Continued) PAGE (D). Oscillating Armature Control Contacts.... 8 (E). Dummy Spring and Flasher Contacts..... 9 (F). Check Contact.................... 10 (G). Time Contact.................... 10 Ratchet Wheel Adjustment.... Time Adjustment.... (A). Oscillating Armature Frequency... (B). Minimum Rated Time Interval...... (C). Variations in Timing.... (D). Maximum Rated Time Interval... General Inspection.... 11 11 11 12 12 12 12 XII Electrical Inspection.................... 12 (A). Neutral Armature Hold-Down......... 12 (B). Clutch Armature Pick-Up............. 12 (C). Clutch Armature Drop-Away.......... 13 (D). Stalling Test..................... 13 xm Contact Resistance...................... 13 XIV Assembly of Base to Relay................. 14 XV Changes Made in Design Details............. 14 (A). Thinner Contact Springs.............. 14 (B). Clutch Armatures.................. 14 ( C). Clutch Knife Edge Studs.............. 15 (D). Shaft and Bearing Tolerance........... 15 (E). Checking Contact with Instantaneous Opening....................... 15 (F). Checking Contact Members............ 15 (G). Gear Train Torque................. 16 (H). Time Contact Upper Stop............. 16 (I). Clutch (Brake) Whee ls............... 17 (J). Special Tests on Relays with Rubber Brake Wheels....................... 18 (K). New Gear Train Adjustment........... 18 (L). Oscillating Armature Control Contact Springs....................... 19 (M). Multiple Front Control Contacts........ 19 (N). Resistance Leads................ 22 (0). Adjusting Key and Shipping Lock...,., 23 2365, p. 2

' ' WABCEl I. FIELD ADJUSTMENT AND TESTS (A). Field adjustment of timing should be made as follows: (1). Adjust segment to the desired time marking. On relays equipped with a combination adjusting key and shipping lock, the key nd of the combination should be inserted in the hole to engage the gear train, permitting adjustment of the segment to the desired time marking. The knurled lock nut of the combination should be loose during adjustment of the segment. After the time interval has been set, the adjusting key should be inverted leaving the key end up and the knurled lock nut tightened. (2). Make several checks of timing, at the service voltage, with a watch, readjusting segment as required so that the desired time is the shortest observed. The variations due to mechanical tolerances (See Section X-C) will then add to the time interval setting instead of shortening it. (3). Readjustment of the timing may be necessary in service when temperatures are more than 50 F. above or below the ambient temperature at the time of the previous adjustment. Changes in service voltage may also require timing readjustment. Higher temperatures and voltages tend to shorten the time interval. The permissable limit in this direction is the point where the timing is down to 90% of the specified timing for the location. (B). Field tests should be made periodically to determine when the relays should be overhauled in the shop. Some types of service will require shorter intervals between shop overhauls than would be necessary for less severe service. Relays should be removed from service when field tests show the following: (1). Timing is appreciably less than 90% or more than 115% of the previous timing, when checked at the same service voltage and at a temperature within 50 F. of the previous temperature. (2). Timing is appreciably less than 85% or more than 120% of the previous timing, when checked with a service voltage 90% or 110% of the previous voltage, and at a temperature within 50 F. of the previous temperature. (3). The clutch armature bobs or breathes, leaving the pole pieces on either side during the timing interval or after the neutral armature picks up. (4). The gear train does not rest against its backstop and fully compress the check contact, when released. (5). The oscillating armature control contacts have excessive blackening due to arcing. (6). The brake wheel has any cuts or tears in its working surface. (Any clutch slippage is also very objectionable.) (7). The clutch armature drop-away becomes less than 67% of the value given in Section XII-C. II, NEUTRAL ARMATURE (A). Armature bracket and pivot screws should be examined to see that pivot screws are not bent and are in proper alignment. A bent pivot screw can 2365, p. 3

WABCD "4v be detected by unscrewing one turn, watching to see whether the armature changes its position with respect to the pole pieces. (B). Armature air gap should have a parallel Pl'!Ysical value of not less than 0. 013 inch. A 0. 015 inch spacer is recommended for actual setting of the air gap. (0, 016 inch if the rust protective coating has been removed from the pole faces.) If it is necessary to repaint the pole faces, we recommend that Union Pole Face Treatment per Instruction Pamphlet U-5038 dated September, 1953, be used. This pamphlet also covers an aluminum paint material for touching up armatures, backstraps and similar parts. III, HOLD DOWN CORES AND POLE PIECES If it becomes necessary to replace or reset the hold-down cores and pole pieces, they should be assembled to the main pole pieces after the neutral armature has been set in accord.. nee with Section II, and adjusted as follows: Insert a 0. 085 inch spacer between the stop pin of the neutral armature and its stop, and hold the armature firmly against the spacer by applying pressure between the stop pin and the pivot serews. Swing the hold-down pole pieces so they hit as flatly as possible against the neutral armature over the entire engaging surfaces, With the armature resting on the hold-down pole pieces it should be impossible to insert a 0. 0015 inch spacer between the armature and pole pieces over any of the engaging surfaces. After this adjustment is made, the screws that fasten the hold-down brackets to the main pole pieces should be tightened without disturbing the alignment, and the dowel pins applied so that the relationship between the hold-down pole pieces and the neutral armature is permanently fixed. The screws securing the holddown pole pieces to the cores should then be tightened and locked in place, and alignment again checked. The hold-down pole pieces should not be disturbed after this adjustment is made. It is important that the adjustment of the hold-down pole pieces be made correctly, as improper adjustment will result in a bobbing of the neutral armature during the time the oscillating armature is operating. This action is undesirable as it results in arcing at the back control contacts on the neutral armature and may result in a re lay failure. IV. CLUTCH The various modifications of the clutch arrangement are discussed in Section XV -B, Present clutch handling is covered in the following: (A). CLUTCH ARMATURE (1), Release spring should be flat with no perceptible pressure against the armature surface. (2). End play on the yoke should be from 0.005 inch to 0.010 inch. Spacer washers should be filed if necessary to obtain this end play. (3). Stop pins should both strike the pole faces at the same time and with approximately the same air gaps (O. 005 inch on present relays). The armature 2365, p. 4

surface should never come into direct contact with pole pieces or yoke. See Section XV-B for discussion of air gaps on earlier relays. (4). The back stop should be adjusted to provide a minimum clearance of 0, 005 inch between the clutch armature and the clos-est point (clamping washer or rivet heads) on the brake wheel. The brake wheel should be turned a full revolution by rotating the ratchet wheel to see that the clearance is never less than the minimum specified. (B). Clutch (Brake) wheel should have its working surface intact without cuts or tears which might cause erratic timing. See Section XV -I for a discussion of various brake wheels used. Heat-treated brake wheels are marked with letter "H" on washer or gear. The reamed hole in the brake wheel should fit freely on the bushing in the yoke with no binding at any point when it is rotated. (C). Clutch (knife edge) studs should be adjusted as follows: (1). Set gear train at 1/3 of the maximum time setting. (2). Adjust knife edge stud, with relay energized, to just touch the brake wheel. (3). Deenergize the rela and measure clearance between the knife edge and the brake wheel. Should be approximately 0. 040 inch.) (4). Readjust the knife edge stud so that the clearance will be approximately 0. 025 inch less than measured in (3). The difference should never be made less than 0. 018 inch and should not be made more than 0. 025 inch without a careful check of the pick-up of the clutch armature with the 0. 005 inch spacer as described in Section XII-B. (5). Clearance after adjustment (4) should normally be from 0. 010 inch to 0. 015 inch and in no case should it be less than 0. 005 inch. (6). Sheet metal lock washers should be bent to hold the hexagonal head of the knife edge stud on one side and the clamping nut on the other side. V. SHAFTS AND BEARINGS (A). Oil carefully all oscillating armature and gear train bearing surfaces, using only Gulf Special Instrument oil, ordering reference UJ41099. The applicator rod and the oil should be kept free from any contamination and the bottle should be tightly capped when not in use. Applicator should be allowed to drain until the drops can be controlled, then one drop shall be allowed to fall on each of the following surfaces: (1). Front half of the main bearing surface of the drive shaft. (2). Rear half of the main bearing surface of the drive shaft. (3). Gear train bearing surface on the drive shaft. (4). Brake wheel bearing surface. (5). Gear train shafts. Since this is a non-spreading oil it should be placed directly on the surface 2365, p. 5

WABCCJ to be lubricated. After the oil drops have been applied, the applicator rod should be wiped against the edge of the bottle opening to remove the surplus drops. The rod should then be used to distribute the drops of oil over the surfaces. Oil must never be allowed to get onto the brake wheel clutch surface. (B). Drive shaft bearings should have proper clearance. Older relays should be checked to see that the bearings in the yoke are at least 0. 2505 inch in diameter. A 0. 251 inch reamer should be used to line ream the bearings if they are too small. (See Section XV-D.) VI. OSCILLATING ARMATURE (A). The air gap should be adjusted as closely as possible to a parallel value of 0. 011 inch before the pole faces are painted (See Section II-B.) After painting, these gaps should not be less than 0, 009 inch or more than O. 013 inch at any point. (B). pieces. The stop pins should hit flatly against the bronze stops in the pole (C). The total stroke of the oscillating armature at the stop pins should be from 0. 140 inch to 0. 150 inch. (D). Side play should not be excessive. Measure the total movement at the end of the armature when the end play and bearing clearance is taken up as much as possible in each direction. A play of not more than O. 020 inch is permissible with new parts while a play of O. 031 inch is considered excessive on repaired relays. A minimum clearance of 0. 005 inch should be maintained between the armature and the yoke surface even if it is necessary to file the corners of the yokes to obtain it. Bared surfaces should be protected with aluminum touch up paint as described in Instruction Pamphlet U-5038, dated September, 1953. VIL GEAR TRAIN (A). End play of between 0. 008 inch and 0. 012 inch must be provided along the shaft to insure free movement of the gear train. (B). Freedom in gear meshing shall be checked by rotating the ratchet wheel by hand. This check can best be made by holding the ratchet stop spring just out of engagement with the ratchet wheel while it is being rotated. (C). Locking spring for the worm shaft, used to move the segment for setting the time interval, should be adjusted for proper meshing of the teeth and for sufficient pressure against the pinion for definite locking. Closer time adjustment is obtained with present worm shaft locking means. See Section XV-K for parts needed to apply new locking to earlier relays O VIII. CONTACT ADJUSTMENTS (A). General Instructions Silver tips should be carefully cleaned before contacts are adjusted. Best service is obtained from a contact surface polished as highly as possible. Care should be taken to avoid the coarse finish resulting from ordinaryfine files. The use of erasers, identified below, is recommended for the final polishing. Eraser 2365, p. 6

WABCC "V'...,, 101018, Dwg. 12750-1 is for use in a drill press, the end of the eraser being rotated over the silver surface. The rotating eraser should touch the silver lightly and should not be held in one place long, as this will overheat the silver contact. Eraser 101019, Dwg. 12750-1 is a hand eraser also used for polishing by stroking the silver in the direction of contact slide. In all cases, the silver should be against solid backing so it does not become twisted to cause beveling of the surfaces. Care should be taken to remove all eraser particles after polishing. The sharp tips of new carbons should be broken slightly by filing in a plane parallel to the springs. A fine file should be used for this operation; #4 equalling file O. 040 inch thick is recommended. After carbons are filed, the following procedure should be followed: (1). All contacts should be cleaned using a lintless cloth covered metal strip moistened with denatured ethyl alcohol to wipe the active silver and silver impregnated carbon contact surfaces. The alcohol should be applied to the cleaning strip from a closed container such as a small oil can in order to prevent contamination of the alcohol. (2). Dry the contacts immediately, using a clean lintless cloth covered metal strip. (3). The contact resistance should then be checked, before and after the relay bases are applied, to values lower than service specification limits. (See Section XIII). It is desirable to obtain as low a value as possible consistent with the characteristics of the type of contact being cleaned. (4). Silver impregnated carbon contacts which will not meet the required values may be sanded with #4/0 metallographic emery paper and again cleaned and dried per items (1) and (2), Occasionally it is necessary to sand and reclean the carbon a second time before the lower limits are met. All screws holding the contact springs, supports., and back contacts should be checked for tightness, All springs should extend straight out in line with the surface of the bakelite support block to which they are attached" When replacing contact springs, avoid bending springs except as necessary to secure alignment with old springs. Contact adjustments when needed, should be made by adjusting the carbons, All springs, except the special control contact spring with the stop, should extend straight out, in line with the surface to which they are attached. Springs with slotted contact tips may be adjusted by bending the tips slightly, if necessary, to make the tips hit the carbons squarely and at the same time. Springs with unslotted contact tips should be adjusted so that, when just touching and when fully compressed, the contact tip touches the front or back tips on at least two points on each side of the tips or makes contact at the center for a distance of at least 25% of its width. Where the contact pieces are not in intimate contact, the opening must be almost imperceptible. 2365, p. 7

WABCD (B). NEUTRAL CONTACTS should be adjusted as follows: (1). The front contacts should be adjusted with a 0.029 inch spacer between the stop pin in the armature and its stop, with the armature held firmly against the spacer and stop by pressure between the stop pin and the pivot screws to bring the neutral armature as close to the pole pieces as the play in the pivots will permit. The carbons should be adjusted so they are in line with, and light is barely perceptible between, the silver tips. A O. 028 inch spacer should allow the contacts to close. (2). Back contacts, except for the special control contact spring with the stop, should be adjusted bybending thestationarymemberandnot the springs, to just open with a O. 062 inch spacer at the main armature stop pin, with the armature held firmly against the spacer and stop by pressure applied on the armature between the stop pin and pivots to bring the armature as close to the pole pieces as the play in the pivots will permit. The back contact opening should be approximately O. 075 inch. (C). NEUTRAL CONTROL CONTACTS This section covers the adjustment of the neutral control contacts on relays equipped with the multiple front control contacts furnished on relays manufactured since December 1, 1948. For adjustments of control contacts on earlier relays see Section XV -M. (1). Control contact springs, except for the special one with the stop, should be in line with each other. (2). Back contacts, except the special control contact with the stop, should be adjusted to just open with a 0. 062 inch spacer at the stop pin as described in Section VIII-B-2. (3). Multiple front control contact, 279637 (See Fig. 6 in Section XV -M), should be adjusted to have an opening of 0. 020 inch between the carbon tip and the special control contact with the stop. (4). Special control contact spring with the stop should be adjusted to just open from its front contact with a stop pin spacer of 0. 010 inch. (5). Stop for special control contact spring should be adjusted to just touch the spring without any apparent pressure when the spring is not against the front or back contact members. (6). Center control contact spring should be checked to see that it is definitely closed with a stop pin spacer of 0. 014 inch or greater. It is permissible for the contact to have appreciable compression when the armature is closed against the 0. 014 inch spacer at the stop pin. (D). OSCILLATING ARMATURE CONTROL CONTACT (1). Normal adjustment of the oscillating armature control contact should be made with the relay tilted as shown in Fig. l, With a 0. 091 inch spacer between the armature stop pin and the stop on the side opposite the contact, the lower contact should just open. With a 0. 090 inch spacer the lower contact should close. The upper contact should be adjusted to have an opening of 9. 030 2365, p. 8

WA8CD inch when the lower contact is closed. The 1 minute relays and the relays with. flasher contacts may be adjusted using a spacer as thin as O. 080 inch for closing of the. lower contact if necessary for positive operation of the oscillating armature at one-half of normal voltage. In any case the relays must meet the anti-stall tests of Section XII-D. (2). Adjustment to overcome stalling may be made, when found to be necessary, by the test of Section XII-D. In such cases the compression of the spring against the lower contact may be increased with a corresponding decrease in the compression against the upper contact, maintaining the O. 030 inch opening of the upper contact.. The compression of the upper contact should not be decreased beyond the point where the upper contact will remain closed with the armature stop pin against a O. 030 inch spacer at cc A".-----LIGHT BARELY PERCEPTIBLE OSCILLATING ARMATURE CONTROL CONTACT SPRING DUMMY SPRING OR FLASHER CONTACT SPRINGS.0111'' SPACER AT STOP PIN Fig. 1. Showing method of applying spacer for adjustment of oscillating armature control contact. (Z). DUMMY SPRING AND FLASHER CONTACTS (1), Dummy (compensating) spring should be adjusted, by raising or lowering the spring stops, to give the flasher frequency listed in Section X-A. The spring pressure against the upper stop should be about the same as against the lower stop, to keep the oscillating armature operation balanced without noticeable "limping". The spring should hit the stops squarely and not on one edge of the spring. (2). Flasher contacts, when provided, should be adjusted using a O. 021 inch stop pin spacer. The spacer should be at the stop pin adjacent to the.flasher contacts for the upper contacts and at the opposite end of the armature for the lower contacts. The spacer may be increased, if necessary, to increase the 2365, p. 9

WABCD frequency of the oscillating armature or, decreased as low as O. 014 inch, if necessary, to reduce the frequency of the oscillating armature. If after this adjustment difficulty is experienced in meeting the one-half voltage test per Section XII-B, it is permissible to remove a maximum of twcl copper washers from the third core, after which it may be necessary to reduce the frequency of the oscillating armature by decreasing the 0. 021 inch stop pin spacer. (F). CHECK CONTACT (See Fig. 2). For adjustment of check contacts on early relays, see Section XV -F. Present check contacts with instantaneous opening should be adjusted as follows: (1). Adjust the gear train back stop to make the insulating arm of the gear train parallel with the top plate when against the stop. (2). With gear train backed away (free from contacts), set the lower contact spring against its stop and adjust the spring and the stop to provide approximately 1/8 inch opening between its contact and the upper contact. (3). Bring the gear train arm against a 0. 020 inch spacer held against its stop and hold there for ( 4). (4). With the lower spring resting on the gear train arm, adjust the upper spring and stop until the contact just makes with the lower spring contact. (5). Remove the spacer from the gear train stop. Check that with the gear train arm against the stop, the upper contact spring moves away from its stop by approximately 0. 020 inch. (6). With the gear train pulled away, as in (2), adjust as follows: (a). Adjust the initial pressure of the upper spring against its stop to 15 grams minimum and recheck per (5) above. (b). Adjust lower contact spring to relieve all pressure against its stop. Spring should just touch stop. (7). With the relay deenergized and the gear train resting against its stop, note that the insulated arm of the clutch armature just clears the upper check contact springs. (8). With the relay energized and the clutch armature picked up against its stop, check that the contact opening is 0. 030 inch minimum. (9). With the gear train set to maximum relay time, energize relay at normal rated voltage until the ratchet has advanced five or six strokes, then deenergize the relay and note that: (a). Gear train arm is resting against its stop. (b). Check contact is closed. (G). TIME CONTACT (See Fig. 4) The time contact (the contact which is closed by the gear train at the end of the time interval) should be adjusted as follows: (1). The upper spring (with the carbon tip) should be adjusted to exert a pressure of 15 grams against its lower stop. 2365, p. 10

(2). The u er sto for the spring with the carbon tip should be adjusted to have an opening of 1 32 inch from the spring. (3). The lower spring (with the silver tip) should be adjusted to exert a pressure of 3 grams against its stop with a contact_ opening of 0. 070 inch between the carbon and silver contact tips. follows: (4). The time contact assembly should be adjusted on its bracket as (a). Set gear train segment to approximately 1/3 of a division above the zero mark. (b). Raise or lower assembly so that time contact just opens. (c). Adjust assembly so that the carbon tip is centered over the micarta tip on the gear train which actuates the time contact. IX. RATCHET WHEEL ADJUSTMENT (A). The ratchet driving pawl, which is carried on a stud fastened to the oscillating armature, should have between 0. 008 and 0. 015 inch side play measured along the stud. This clearance can be set by means of thicker or thinner spacer washers between the pawl and the pin which keeps the pawl on the stud. (B). The ratchet stop spring shall be adjusted so that it exerts about 2. 5 ounces (2. 0 oz. min. - 2. 75 oz. max.) pressure against the ratchet wheel when the tip of a ratchet tooth is touching the spring. The location of the spring shall be determined by the operation of the oscillating armature so that with a finger drag to tend to hold it from rotating, the ratchet wheel is advanced one tooth for each complete operation of the oscillating armature. After proper adjustment is obtained, the screw holding the spring should be tightened in place and then locked by means of the lock washer, special attention being paid to see that the screw head does not ride on the edges of surfaces adjacent to the slot but clamps the spring tightly in place. It is important that only springs applied by the U.S. & S. Division be used for the ratchet wheel stop as these springs are especially treated to give long satisfactory life in this service. X. TIME ADJUSTMENT (A). Oscillating armature frequency should be adjusted, with the gear train set for maximum interval, by increasing or decreasing the pressure of the dummy spring or flasher contacts as described in Section Vlll-D. The frequency in cycles (complete operation of the oscillating armature in reversing from normal to reverse then back to normal) should be adjusted as closely as possible to the rated value given in the follovring table. Do not start measuring the frequency until the gear train has moved away from the lower check contact spring. 5 to 60 second relay - 107 cycles per minute 10 to 120 second relay 53. 5 cycles per minute 0.5 to 6 minute relay 33. 5 cycles per minute 1 to 12 minute relay 39 cycles per minute 2 to 24 minute relay 19. 5 eye les per minute 2365, p. 11

WABCD (B). Minimum rated time interval should be checked, after setting gear train segment to the first graduation after zero, with the coils energized at the rated voltage. The time from application of the voltage until the neutral armature picks up should be checked with a watch to see that it is reasonably close to the minimum rated value. Allowable variations in successive operations at same setting (see paragraph C) should be distributed above and below the minimum rated time by raising or lowering the time contact on its support bracket. (C). Variations in timing for successive operations at any gear train setting, due to mechanical clearances in the gear train mechanism, may be as long as given in the following table: 5 to 60 second relay - 1 second 10 to 120 second relay - 2 seconds O. 5 to 6 minute relay - 6 seconds 1 to 12 minute relay -12 seconds 2 to 24 minute relay -24 seconds (D). Maximum rated time interval should be checked, after setting the gear train segment to the last graduation, with the coils energized at the rated voltage, The timing, when checked with a watch, should be within 3 percent of the maximum rated value. If the observed timing does not meet this allowance, recheck adjustment of the time contact, ratchet wheel stop spring and oscillating armature frequency. It might be necessary in some cases to make a slight change in the oscillating armature frequency to give proper timing. XI. GENERAL INSPECTION After the relay is completely adjusted and tested the following items should be rechecked: (A). Carbon contacts should be tightly clamped and not cracked. (BL Screws and nuts should be tight and locked with sheet metal washers. (C). End play of drive shaft and gear assembly should be 0. 008 inch to 0. 010 inc ho (D). Gear train shall move freely over entire range of travel at all time settings. (E). Spring lock on the gear train adjustment must properly hold the worm gear shaft from turning due to vibration. XIL ELECTRICAL INSPECTION (A). Neutral armature, with the relay energized and oscillating armature operating, should be held securely against the hold-down pole pieces without any breathing or bobbing and the control contacts at the center of the armature should not arc. (B). Clutch armature ick-up shall be observed, using a metal spacer 0. 005 inch thick approximately 1;4 inch wide by 1/2 inch long between the knife edge stud and the brake wheel as follows: (1). Energize relay at one-half of normal rated voltage. 2365, p. 12

WABCD "4fV' (2). Clutch armature shall pick up with both stop pins against the pole pieces and shall not bob or breathe during the time interval and shall remain picked up after the time contact closes. The neutral armature may or may not pick-up at this voltage. (3). Eliminate bobbing of the clutch armature by decreasing pressure of the knife edge stud against the brake wheel by readjusting per Section IV -C so that the difference between measurements IV-C-3 and IV-C-4 will be reduced. (A difference of at least 0. 018 inch must be maintained.) (C). Clutch armature drop-away should be tested after the completion of the time interval with the relay energized at the normal rated voltage. The energization should be decreased until the clutch armature drops away from its pole pieces and permits the gear train to drop against its back stop, The test should be repeated several times with the knife edge stud engaging the brake wheel at several different points around the circumference. Drop-away should be not less than: 0, 24 volt for 0. 32 volt for 0. 40 volt for 0.48 volt for 0. 56 volt for 6-volt relay 8-volt relay 10-volt relay 12-volt relay 14-volt relay (D). Stalling test on the oscillating armature should be made, with the relay operating with one-half of normal voltage and before the time contact is closed, in accordance with the following: (1). Grasp dummy spring by hand when it is against its upper stop. (2). Slowly allow the armature to move so that the lower oscillating armature control contact is open. (3). Carefully release the hold on the dummy spring and see that the armature has a definite forceful pull on it to cause it to move one way or the other. (4). Repeat (1), (2), and (3) for other positions of the contact spring tip between the upper and lower contact members to see that there is no position, except when actually against a contact and arcing, that the armature will remain without starting to again oscillate. (5). If the armature can be stalled by hand, increase the compression of the lower control contact as described in Section VIII-D-2. XIII. CONTACT RESISTANCE Contact resistance of front contacts should be checked after the end of the time interval with the neutral armature picked up. Back contacts and the check contact should be tested with the relay deenergized with the neutral armature down and the gear train against its back stop. Resistances should be checked after cleaning the contacts and should not exceed the following values: Front Neutral Contacts Silver to Silver-Impregnated Carbon - 0.09 ohm 2365, p. 13

WABCC Back Neutral Contacts Silver to Silver Silver to Silver-Impregnated Carbon Check Contact Silver to Silver-Impregnated Carbon - 0. 03 ohm - 0.18 ohm - 0.18 ohm XIV. ASSEMBLY OF BASE TO RELAY It should be noted that the gaskets seal the relay tightly and that the corners do not overhang the gaskets. The nuts holding the base of relay should be tightened carefully in order not to put unnecessary strains on the top plate. This can be accomplished by bringing the nuts to a cchand-tight" position where the base just starts compressing the gaskets, and then giving the nuts one complete turn with the wrench to tighten, after which sealing should be applied. XV. CHANGES MADE IN DESIGN DETAILS This section summarizes the major improvements made to DT-10 relays since they were first placed in production. For more complete details on some items, see other parts of this specification referred to in the following: (A). Thinner Contact Springs. Present design (since September, 1935) uses O. 0126 inch (#28 B&S) phosphor bronze or 0. 010 inch (#30 B&S) nickel springs for neutral contacts, except for one contact in the control circuit. The earlier relays used O. 0113 inch (129 B&S) nickel springs. We recommend that the early springs identified by "11" on back edge, be replaced by ordering contact springs 170726-Dwg. 8385-Sh. 2336. Six springs are required for each relay. The one back neutral control contact with the stop has not been revised. (See Section VIll-A.) (B). Clutch Armatures with counterweights furnished on early relays were replaced with ones having spring release with greatly improved drop-away characteristics. From January, 1932 to March, 1940, clutch armatures complete (with release springs and knife edge stud) 182087 -Dwg. 8157-Sh. 404 were used. These required two studs 182084-Dwg. 8114-Sh. 831 and two nuts 72948-Dwg. 8109-Sh. 383 if applied to relays made before January, 1932. See Fig. 3 and also Section IV-A. Relays made since March, 1940, use clutch armatures complete with release spring, knife edge stud, and check contact operating stud) 109858-Dwg. 8157-Sh. 469. If relays made before January, 1932 are to be revised, this armature should be ordered if the instantaneous opening check contact Fig. 2 is also being applied. See also Section IV -A. Since about September 1955, clutch armatures with the same reference as in the previous paragraph have a new design adjustable bracket type mounting for the check contact opening stud. The adjustable type mounting of the stud permits alignment of the stud by means of a contact bending tool. This new clutch armature is interchangeable with older style armatures having 0. 005 inch air gaps. 2365, p. 14

WABCC "'4'o"V' Clutch armature air gaps were 0. 015 inch until May, 1945, when a change in the magnetic material necessitated a decrease in the air gap to give proper holding. Relays from May, 1945 to November, 1945, had air gaps 0.010 inch or O. 008 inch. Relays from November, 1945 to September, 1947, in order to match the rubber brake wheels, had Oo 004 inch air gaps while all later relays have O. 005 inch air gaps. Ordinarily, there is no need to change the clutch armature air gaps unless the old brake wheels are being replaced with rubber brake wheels. In this case it is recommended that the air gaps be reduced to O. 005 inch. (C). Clutch knife edge studs of copper plated hardened steel have, since February, 1935, replaced the nickel plated knurled brass studs used on early relays. The knife edge studs give positive, effective holding of the clutch wheel, thereby contributing to more accurate timing. (D), Shaft and bearing tolerances have been different since April, 1933. Relays made prior to that time should be checked to insure correct shaft clearance. The bearing holes should be 0. 2505 inch minimum and may be reamed with a 0.251 inch reamer. (E). Checking contacts with instantaneous opening have been furnished since March, 1940, Fig. 2 shows this arrangement and gives ordering references for the parts involved. (F). Checking contact members have been reversed on all relays made since August, 1932. Formerly, when the silver contact was below and the impregnated NUT UM72948-8109- SH. 383 GEAR TRAIN BACK STOP UM109466-8735-SH. 950 SPRING STOP UM216198-8735 - SH. 950 PIN UM156497-8097-SH. 409 UPPER CHECK CONTACT SPRING UN217258-8385-SH.2369 WASHER UM161194-8112-SH. 66 ENGAGING EDGE OF CLUTCH KNIFE EDGE STUD UM160745-8114- SH. 433 LOCK WASHER UM 134516-8486 - SH. 368 PLATE WASHER Ut.1217185-7828-SH. 247 SPLIT PIN UM161189-8097-SH. 852 CLUTCH ARMATURE COMPLETE (WITH KNIFE EDGE STUD, RELEASE SPRING & CHECK CONTACT OPERATING STUD.) UN109858-8157- SH. 469 Fig. 2.,, Showing latest clutch armature and instantaneous opening checking contact references. 2365, p. 15

WABCD carbon contact above, there was some possibility of dirt collecting on the flat silver surface. Interchanging the two members places the carbon with its oblique surfaces beneath and gives better assurance of maintaining a clean, low-resistance contact. It is recommended that the early retays be modified to use the latest arrangement shown in Fig. 2. When modifying relays made from August 1932 to March, 1940, it is also necessary to remove one of the two studs (182084) which give tension to the old clutch armature release spring. Remove stud nearest check contact and replace with a dummy screw, or cut off the tip and allow the stud to remain as a dummy. The following Fig. 3 is given to show references for the checking contact parts furnished from August, 1932 to March, 1940. When relays are being modified, the parts shown in Fig. 2 should be used. Adjustments of Fig. 3 checking contact arrangement should be as follows: (1), Adjust the gear train back stop to make the insulating arm of the gear train parallel with the top plate when against the stop. (2). With the gear train backed away to clear the contacts, set the lower contact spring against its stop with no perceptible pressure and to give approximately 1/8 inch contact opening. (3). With a 0. 020 inch spacer between the gear train and its stop, adjust the upper spring and its stop so that the contact is just made and the spring has at least 10 grams pressure against its stop. GEAR TRAIN BACK STOP UPPER CHECK CONTACT SPRING UN160739 8735-SH. 688 CLUTCH ARMATURE COMPLETE (w1th KNlf[ [OGE: STUD L RE:LEASE SPRINGS) Fig. 3... Showing checking contact arrangement used from August, 1932 to March, 1940. ( G). Gear Train torque has been increased on the 2 minute and 6 minute relays only, by an added weight, since March, 1940. This assures positive closing of the checking contact when the relay is deenergized, On relays for longer time intervals the larger gear trains have enough inherent weight without additional weight. The order reference for the "added weight" is 109839-Dwg. 9672-Sh. 225. The method of assembly of the added weight is shown in Fig. 6. (H). Time contact upper stop, since April, 1941, has been modified to be positioned directly over the center of the contact tips. This is to prevent dis- 2365, p. 16

.. WABCD tortion of th.e ttme contact springs due to rough handling during shipment. Ordering reference for the new part is "Contact Stop, 222866-Dwg. 8735-Sh. 975' (See Fig. 4.) ---- Fig. UM193660-8109-SH. 484 E-===-::;t...-t---UPPER STOP UM222866-8735-SH. 975...-..c.-..--UPPER SPRING UN160363-8385-SH.2218 mrrfi5,rm-llll-lqwer spring 4... Time Contact Assembly un160jse-e3es-sh.2211 (I). Clutch (brake) wheels on early relays used cork composition until September, 1943, when rubberized cork was used. Both materials gave very good service except that an occasional wheel would have its surface cut or torn with a resulting erratic time interval. Since December, 1945, relays have been e quipped with rubber brake wheels which may be distinguished by their solid black color. Rubberized cork brake wheels are variegated brown and black in color. Cork brake wheels were dyed black but after considerable service the black working surface wore off. Relays with rubber brake wheels in service with original inspection dates between December, 1945, and January 8, 1948, may give some trouble if they are in service in latitudes subject to temperatures below 32 degree F. These should be handled in accordance with the following program. Relays in service under milder climatic conditions will be considerably less susceptible to improper operation. (1). Relays, with rubber brake wheels, made from December, 1945, to April, 1947, had adjustments which did not provide sufficient margins to give proper operation in cold weather. The rubber material increased in hardness at cold temperatures so that the knife edge studs had excessive pressure against the brake wheels, which caused too much load on the clutch armatures. This condition was also aggravated by the situation described in following item (3). Difficulty may be expected from some of these relays during cold weather and it is suggested that these relays be shopped to replace the brake wheels with ones which have been heat-treated (stamped with letter "H".) See Item (3). Relays should then be adjusted as covered by Section IV-C. (2). Relays, with rubber brake wheels, made from April, 1947 to January 9, 1948, have had the benefit of factory adjustments which provide sufficient margins to take care of the brake wheel hardness at low temperatures, but may be affected as indicated by Item (3). Most relays of this group will give satisfactory service and may be left in service until the regular shopping period when the brake wheels should be replaced as covered by Item (3). (3). All relays equipped with rubber brake wheels and manufactured prior to January 9, 1948, may develop excessive knife edge stud pressures due to the diameter of the rubber wheels increasing slightly in the first few months 2365, p. 17

' ; WABCD service after assembly at Swissvale. This is caused by the dissipation of internal strains in the rubber that were produced during riveting of the clamping plates. Heat-treated rubber brake wheels stamped with letter "H" will be exchanged for the untreated wheels, without charge, to take care of replacement. U. S. & S. Division should be notified as to the total number needed to take care of replacements during a six-month period. Brake wheel 160836-Dwg. 8424-Sh. 258 is used for relays with time intervals of 1, 2, and 6 minutes, while brake wheel 181102-Dwg. 8424-Sh. 270, is used for the 12 and 24 minute relays. New brake wheels will be furnished, no charge, with the understanding that the old ones will be returned to Swissvale for credit. (J). Special tests on relays with rubber brake wheels should be made if the relays are not equipped with the multiple front control contacts. These relays will have Swissvale inspection dates between December, 1945, and December, 1948. The special tests, which are in addition to those covered in Section XII-B, should be made as follows: Fig. 5. (1). Apply tool 273630-Dwg. A-2586-Sh. 92 to the clutch armature per (2). Energize the relay at the minimum voltage and close the time contact momentarily by hand to pick up the neutral armature. (3). Open the time contact. Neutral armature must drop and the clutch armature must remain in energized position. (4). Deenergize relay and rotate ratchet wheel by hand to bring a different part of the brake wheel into proximity of knife edge stud. Repeat (2) and (3). (5). Deenergize relay and remove tool 273630. Fig. 5... Showing application of testing tool. (This has limited usage, see text.) (K). New gear train adjustment has been furnished on all relays shipped since June 2, 1948. This change permits closersettingof the gear train segment than was previously possible. Locking formerly was accomplished by a flat spring 2365, p. 18

.. WA8CD with a rectangular slot which engaged the square end of the worm shaft. This meant that the shaft could be turned and locked only in 90 steps. The new adjustment uses any standard DT-10 relay key applied through the top plate opening to engage a square end on a new worm shaft which is machined with a 16-tooth pinion section. The locking is by means of three teeth on a formed bronze spring which engage the teeth of the pinion on the worm shaft. Turning the key forces the shaft and pinion to rotate against the action of the spring to bring new pinion teeth into engagement with the teeth in the locking spring, progressively either forward or backward. Relays in service can be modified per Fig. 6 as follows: (1). Order one each of the following parts per relay: Worm shaft 273287-Dwg. 8424-Sh. 317 Locking spring 273286-Dwg. 8735-Sh. 1107 Pin UJ49804-Dwg. 10301-Sh. 21. (2). Remove pin UJ49804, worm shaft, and locking spring (with the rectangular locking hole). (3). Apply new locking spring 273286 and new worm shaft 273287, reassembling worm and spacer washers originally used. (4). Drill O. 0635 inch diameter (#52 drill) hole through the shaft using the old hole in the worm as a guide. (5). Check the locking spring for proper meshing of teeth and for sufficient pressure against the pinion for definite locking. WORM SHAFT UM273267-8424-SH. 317 ---- LOCKING SPRING.,,... UM273286-8735-SH.1107 PIN REF. 18 UJ49804-10301-SH. 21 ADDED WEIGHT UN109839-9672-SH.225 (see SECTION xv-c.) Fig. 6... Showing assembly of new gear train adjustment (L). Oscillating armature control contact springs since January, 1945 have been of heavier gauge material. The old springs identified with a "7" at the back edge should be replaced by new contact springs 176829-Dwg. 8385-Sh. 2443, identified with 11 8'' at the back edge. This will give increased contact pressure with reduction in contact resistance and improved reliability. (M). Multiple front control contacts have been furnished on all relays since December 1, 1948. This change was made to provide an improved internal 2365, p. 19

. ' WABCO circuit that results in the time contact being by-passed after the neutral armature is in the energized position. This eliminates dropping out of the relay due to vibration on the time contact. All DT-10 relay! inspected after December 1, -1948, and carrying the improved circuit, can further be identified by the use of a circuit diagram on the relay back strap that has a red background. The previous circuit had a black background. Relay references remain unchanged. Some railroads have equipped their relays with external jumper leads which used one of the front neutral contacts to by-pass the time contact, thus leaving only three (3) neutral contacts available for external circuits. The improved circuit arrangement results in all four neutral contacts being available for use in external circuits. If the relays have been modified to have the multiple front control contacts, the external jumpers should be removed. Earlier relays can be modified to have the new multiple front control contacts by ordering SBM 279639, which includes all of the new parts referred to in Fig. 7, which shows the new assembly. This figure also gives information for the internal revisions necessary when the change is made. A y CONTACT FINGER UM279838 SH. 89-12748 CLAMP UM233321 SH. 433-8486 SPEC JAL CONTROL CONTACT WITH STOP HEEL CONNECTOR F'ASTENEO TO POST A B - VIEWED FROM BOTTOM 1, Lead "X" must be moved from binding post "B" to "A". 2. Leads "Y" must be transferred and soldered to 279638. 3. 279638, 279637, etc., are assembled instead of contact Ref. 134, Cat. Plate E-5206. 4. Adjust contacts in accordance with Section VIll. Fig. 7... Showing internal revisions and assembly of multiple front control contact to DT-10 relay 2365, p. 20

WA8CD "4etY' NEW WIRING DIAGRAM PLATE LONG LEADS --..._-_ RESISTANCE LEADS BINDING POST II B II BINDING POST II A" 1. Replace wiring diagram plate, with black background, on back strap with new plate UJ630189 having red background. 2. Change coil lead connections to agree with new wiring diagram plate. This requires transposing the two coil leads on binding post "A" with the one coil lead on binding post "B". 3. Remove celluloid tag marked "S" from binding post "B" if relay is equipped with this tag. Earlier relays did not have this tag. Fig. 8. Showing external revisions necessary for application of multiple front control contact. Fig. 9. Showing schematic diagram of DT-10 relay equipped with the multiple front control contact. 2365, p. 21

WABCD Fig. 8 covers the external revisions necessary when the multiple front control contacts are applied, while Fig. 9 is the schematic wiring diagram of the revised relay. Present and modified earlier relays should have their control contacts adjusted in accordance with Section VIII. Earlier relays which are not modified to have the multiple front control contacts should have their control contacts adjusted in accordance with the following: (1). Back control contacts, except the contact spring with the stop, should be adjusted to make contact at the same time as the standard neutral back contacts as covered by Section VIIl-B-2. (2). The back control contact spring with the stop should be adjusted to have a 0. 040 inch contact opening when the relay is energized. The spring with the relay energized, should rest against the stop with no apparent pressure. (3). The one front control contact should be adjusted to just open with a 0. 016 inch spacer at the armature stop pin. A 0. 015 inch spacer should allow the contact to close. (N). Resistance leads have been furnished on all relays manufactured since November 1951. This special 400 ohm resistance lead functions as an arc suppressor to protect the oscillating armature control contacts and it is recommended that railroads purchase a resistance lead for each older style DT-10 relay in service. Fig. 10 shows the application of the resistance lead to modern DT-10 relays and old style DT-10 relays which have been modified to have multiple front control contacts. Fig. 11 shows the application of the resistance lead to old style DT-10 relays not equipped with multiple front control contacts. The resistance lead can be applied to a relay in service without removing the base. First attach one end to the positive (+) control post. Then if the relay is equipped with multiple front control contacts, the other end of the lead is attached to the front post of the four coil-connecting posts in the front of the relay as indicated in Fig. 10. For application to relays not equipped with multiple front control contacts this end of the lead is attached to the right hand post of the four coil connecting posts in the front of the relay as indicated in Fig. 11. Ordering reference for the resistance lead is UJ720345-Dwg. 9065-Sh. 414. Fig. 10... For application to DT-10 relays equipped with multiple front control contacts. 2365, p. 22