Memshield - ACB Ratings & Specifications

Transcription

1 Memshield Memshield - ACB Ratings & Specifications Rating and specifications Current rating, A List No Number of poles RATED CURRENT (A) [In] IEC, BS, VDE, AS Neutral pole ampere frame (A) RATED PRIMARY CURRENT OF OVERCURRENT TRIP DEVICES [ICT] (A) (For general feeder circuit use) RATED CURRENT OF OVERCURRENT TRIP DEVICES [Io] (A) (For generator protection use) [Io] is the generator rated current RATED IMPULSE WITHSTAND VOLTAGE [Uimp] (kv) AC RATED INSULATION VOLTAGE [Ui] (V) 0 RATED OPERATIONAL VOLTAGE [Ue] (V) 8 AC RATED BREAK. CAP. (ka r.m.s.)/make CAP. (ka peak) IEC 47- with Inst. 60V BS EN [Ics] =00% [Icu] 600V CEI EN V up to 45V 60V 600V up to 500V DC RATED BREAKING CAPACITY DC 3 50V DNV with Inst. 660V 600V 480V up to 480V LR with Inst. 660V 600V with Inst. 480V up to 480V AB with Inst. 660V 600V 480V up to 480V GL with Inst. 660V 600V 480V up to 480V BV with Inst. 660V 600V 500V up to 500V SHORT TIME WITHSTAND sec CURRENT [ICW] (ka) 3 sec Latching current [ka] UTILIZATION CATEGORY OPERATION TIMES Total breaking time (s) Spring charging time (s) max. Closing time (s) max. OUTLINE DIMENSIONS (mm) Fixed type a b b c a 0 c d d Draw-out type a b b c a 0 c d d Weight (kg) draw-out type MACB06 MACB MACB6 MACB0 MACB5 MACB3 MACB Io Io Io Io 30 5 Io Io Io <Io 60 30<Io <Io <Io <Io <Io <Io <Io <Io <Io <Io <Io Io Io <Io Io Io /46. 50/05 50/05 50/05 50/05 50/05 50/05 30/63 50/05 50/05 50/05 50/05 65/43 65/43 35/ /43 65/43 65/43 65/43 85/87 85/87 35/ /43 65/43 65/43 65/43 85/87 85/87 /46. 50/05 50/05 50/05 50/05 50/05 50/05 30/63 50/05 50/05 50/05 50/05 65/43 65/43 35/ /05 50/05 50/05 65/43 80/76 80/76 40/40 40/40 40/40 40/40 40/40 40/40 40/40 35/ /43 65/43 65/43 65/43 /5 85/87./ /8 35./8 45.3/ / / /6 50.6/6 50./6 66./68 37/0. 7.6/ / / /0.5 /5. 35/8. 50/4.6 50/4. 50/ /6 65/57. 35/77. 65/45 65/45 65/45 65/45 85/03 35/77. 50/ 50/ 50/ 50/ 65/45 /5.4 35/8 35/8 35/8 45/06 45/06 30/76 50/6 50/6 50/6 50/6 65/68 35/0. 65/0.5 65/0.5 65/0.5 65/0.5 65/0.5 35/ / / / / /0.6 35/ /.3 50/.5 50/6. 50/ / B B B B B B B NOTES: :Values in open air at 40 C (45 C for marine applications). 3 :DC rating is for special application. For further details, contact MEM Ltd. (500V) 5 :Approval pending. 6 :Full rated neutral pole available on request :For vertical terminals, d = mm. :Rated operational voltage depends on applied standard: 60V according to IEC47- :Only applied to 3 pole ACBs. :Rated insulation voltage depends on applied standard: 000VAC according to IEC47- :The application of I.T. systems at this voltage is not permissible RATINGS UPTO 6300A ARE AVAILABLE ON REQUEST - FOR FURTHER DETAILS CONTACT MEM LTD. (500V) 8

2 Memshield - ACB Ratings & Specifications Memshield Internal resistance, reactance, power consumption LIST NO: MACB06 MACB MACB6 MACB0 MACB5 MACB3 MACB40 DC Internal (mw) Draw-out type resistance (per pole) Fixed type Reactance (mw) Draw-out type (per pole) Fixed type AC Power(W) Draw-out type consumption Fixed Type Note: The power consumption shown above is measured on the basis of internal AC resistance for 3 poles De-rating BASED AMBIENT TEMP LIST NO: MACB06 MACB MACB6 MACB0 MACB5 MACB3 MACB40 STANDARDS ( C) IEC47-40 (Standard ambient temperature) BS EN VDE 0660 Part AS Dielectric withstand voltage Accessories CIRCUIT 50/60 HZ Main circuit Between terminals all terminals to earth AC3500V minute Auxiliary switch all terminals to earth AC500V minute Undervoltage trip AC Rating terminals - 0 to earth AC500V minute terminals - to earth AC500V minute DC Rating all terminals to earth AC500V minute Shunt trip all terminals to earth AC000V minute Overcurrent trip all terminals to earth AC000V minute Motor charging closing AC00-50V AC000V minute all terminals to earth control circuit DC00-0V DC4-48V all terminals to earth AC500V minute Other Accessories all terminals to earth AC000V minute Note: The values shown above are those measured on new parts and cannot be applied to components' terminals in the ACB.

3 Memshield Memshield - ACB Types of Mounting Draw-out type Fixed type The draw-out type consists of a circuit breaker and a draw-out cradle. The circuit breaker can be removed from the cradle. There are four circuit breaker positions CONNECTED, TEST, ISOLATED and REMOVE. The switchboard panel door can be kept closed in CONNECTED, TEST and ISOLATED positions ( shut-in three positions ). Connected position Indication CONN. Control circuits Main circuits This consists only of the circuit breaker with fixings to allow it to be mounted permanently inside the switchboard. Main circuit terminals Standard terminal arrangements are either horizontal or vertical type. (Horizontal and vertical types are available for MACB06, MACB, MACB6 and MACB0). Front connections are also available. Please refer to the table below and specify the required connection method at time of ordering. Terminal Arrangement Breaker Type Of Horizontal Vertical Front List No Mounting Terminals Terminals Connections Both main and control circuits are connected for normal service. Test position Indication TEST The main circuit is isolated and the control circuits are connected. This position permits operation tests with the switchboard panel shut. 3 Isolated position Indication ISOLATED MACB06 MACB MACB6 MACB0 MACB5 MACB3 MACB40 Draw-out Fixed Draw-out Fixed Draw-out Fixed Draw-out Fixed Draw-out Fixed Draw-out Fixed Draw-out Fixed Both main and control circuits are isolated. The switchboard panel door can be shut. Earth circuit still connected. Note:- : Standard : Optional : No or not available 4 Remove position The ACB is completely removed from the cradle. Horizontal Terminals Vertical Terminals 0

4 Memshield - ACB Accessories Memshield Accessories are factory fitted and should be specified when ordering. An order form is shown on P48. Door interlock The door interlock prevents the switchboard door from being opened when the breaker is CLOSED. The door can be opened only when the breaker is OPEN. It is also fitted with a lock release. Installation of the door interlock requires simple drilling of the switchboard panel door. Hinge can only be fitted on the RIGHT HAND SIDE as shown in the opposite diagram ø0 (Front view) ø7 50 Panel door 70 Dust plate 50 (Plan view) Breaker mounting hole Hinge A (min.) Breaker A B (3P) B (4P) MACB-06,,6,0, MACB MACB-3, A B (min.) (min.) Panel door Door interlock 0 5 Lifting Truck Breaker mounting position *50 max ACB front panel Lifter List no D W H Weight (kg) AWT-B Dimensions (mm) AWT-B The loader is a variable size type to suit all frame sizes of Memshield ACBs (3 and 4 pole). Panel door Size change is readily done by adjusting the loader. Maximum safe working load (SWL) : 50kg Maximum lifting height : 850mm Minimum passage width : 800mm 300 mm Note: * If distance exceeds 50mm, contact MEM Ltd. (500V) D H W ARC GAS BARRIER The Arc Gas Barrier reduces the air gap requirement between the top of the ACB and other electrical equipment or earthed metal. See outline dimension drawings for details. The barrier can be installed with the cradle, for the draw-out type breaker. The arc gas barrier is a heat proof, flame-resistant insulating plate. CARRYING ROLLERS The carrying rollers are necessary when the lifting truck is used. The rollers can also be used for moving the breaker on the floor. METAL-CLAD TYPE The metal-clad type consists of a draw-out breaker, housed in a steel enclosure. A load centre is readily constructed by simply placing metal-clad units one upon another.

5 Memshield Memshield - ACB Accessories OPEN PADLOCK Permits the ACB to be padlocked in the OPEN position, this is fitted as standard. Max. 3 padlocks (hasp size ø6 to ø8mm) can be fitted (not supplied). CARRYING HANDLE For use with hooks, ropes etc when lifting the breaker. PUSH-BUTTON PADLOCK COVER Prevents unauthorised operation of the manual CLOSE and OPEN buttons. Padlock hasp size ø6 to ø8mm (not supplied). Dustplate Provides a dust proof seal between the ACB front panel and the cut-out on the switchboard panel when the breaker is located between the CONNECTED and ISOLATED position. Special environment specification Cold Climate Treatment Specify this treatment when the breaker is used in cold areas. Specification: 40 C storage temperature -5 C operating temperature (no condensation or freezing). Anti-Corrosion Treatment Anti-corrosion treatment permits the use of the breaker in a corrosive atmosphere. Contact MEM Ltd. (500V) for further information. Tropicalization (Fungus and Moisture Treatment) Specify this treatment when the breaker is used under high temperature and high humidity conditions: Up to 60 C ambient temperature and up to 5% relative humidity (no condensation). Door flange Earthing device Covers the panel cut-out on the switchboard. The panel cut-out should be greater than the standard size shown in the outline dimensions section of 50mm x 70mm. We would recommend to use a cut out of 60mm x 80mm. There is a growing demand in L.V. distribution for greater protection against electric shock particularly during periods when maintenance work is being carried out on the main busbars or cables. A safe and economical way to meet this requirement is to apply system earthing via the normal service breaker. Earthing devices (optional) on Memshield ACBs comprises; Permanent parts which are factory fitted and are mounted on the ACB chassis and body to enable the ACB to receive the portable parts. Portable parts are supplied in loose kit form and are fitted on to the ACB body by the customer's engineer. This converts the ACB from a normal service device to an earthing device. For further information contact MEM Ltd. (500V) for details.

6 Memshield - ACB Accessories Memshield Key interlock The key interlock is a system of interlocking between breakers, each fitted with a lock-inopen type key lock *The key must be inserted to release the lock before the breaker can be closed * The breaker must be opened and locked in the open position before the key can be removed Utilising the lock-in-open type key lock feature and using keys less than the number of the key-locked breakers, an effective and reliable interlock system is formed. can be supplied with a cylinder lock fitted or with a provision for Castell lock. In the latter case, use Lock Type FS (angular movement 65 o clockwise to trap key) Castell Locks Ltd. EXAMPLE: Prevention of parallel connection of two sources with a bus tie breaker. SOURCE SOURCE Breaker Breaker SOURCE SOURCE SOURCE SOURCE Breaker Breaker Breaker Breaker Bus-tie Breaker 3 Bus-tie Breaker 3 Bus-tie Breaker 3 Loads Loads Loads Loads Loads Loads Breaker 3 cannot be closed Breaker cannot be closed Breaker cannot be closed IP cover Mechanical interlock Mounted on the switchboard panel door to provide IP54 degree of protection as defined in IEC5. Horizontal type Wire Vertical type Contact MEM Ltd.(500V) for the details of vertical type with 3 ACBs. P C P C P C Rod N N N 60 P Select the required pitch from the table below: P N *Min 575mm If you require to drawout the ACB with AOR-B to the isolated position, an additional depth frame is required with the IP54 cover. Please specify at the time of ordering. Interlock Pitch of ACB P(mm) between (PC line to PC line) MACB06 MACB MACB6 MACB0 MACB5 MACB3 MACB40 * Minimum pitch (575mm) is possible if the proper insulating distance is obtained. For larger pitch (max. 00mm) contact MEM Ltd.(500V) for details. 3

7 Memshield Memshield - ACB Accessories Auxiliary switch assembly Close-Open cycle counter Auxiliary switches electrically indicate the open-closed status of the breaker. For Draw-out Type, the auxiliary switches operate in the CONNECTED and TEST positions only. However, where marine classification society s rules apply, they operate in the CONNECTED position only. Options include; A B, 5A 5B, 0A 0B. This device counts and indicates the number of close-open cycles. Key lock The key lock is available in two types: lock-in-open type to lock the breaker in the OPEN position, or lock-in-closed type to lock the breaker in the CLOSED position. Auxiliary Switch Ratings Rated Voltage Resistive Lamp **Inductive Motor AC5-500V 7A 5A 7A 7A DC30V 7A 5A 7A 7A DC5V 7A 5A 5A 5A DC50V 7A 5A.5A.5A Note: The minimum current limit is 0mA at 4V. DC ** (AC cos ø over 0.4 DC L/R below 0.007) Trip indication switch Operation of the trip indication switch varies depending on which device trips the breaker and whether or not the closing springs are charged. Rating Load Resistive Lamp Inductive Motor AC5-50V 7A.5A 6A A DC30V 6A 3A 6A 3A DC5V 0.6A 0.A 0.6A 0.A DC50V 0.3A 0.05A 0.3A 0.05A Note: * Optional. The trip indication switch can be made inoperative for a manual operation. Please specify at time of ordering. Breaker tripped by Overcurrent trip (OCR) Shunt trip Undervoltage trip * Manual opening by PUSH-TO-OPEN button Remote opening Undervoltage Condition Operation of trip indication switch Closing springs charged Switch is ON for 40ms, then reset to Switch remains ON until undervoltage condition is restored to normal. Switch remains ON until PUSH-TO- OPEN button is released Closing springs discharged Switch remains ON until closing springs are charged Switch remains ON until closing springs are charged after undervoltage condition has restored to normal Switch remains ON until closing springs are charged after PUSH-TO-OPEN button is released Automatic changeover controller An automatic mains/generator changeover system can be achieved by utilizing this device with a pair of mechanically interlocked ACBs, each fitted with a motor operator, shunt trip and auxiliary switch. If one or more phases fail on mains supply, the device will trip the mains circuit breaker and start the generator. Once up and running (85% of Ue) the generator circuit breaker will close. If mains voltage should return the generator circuit breaker will trip, mains circuit breaker will close and the generator will continue to run on 'No load' for a preset cool down period. Contact MEM Ltd. (500V) for further details. Specifications (Ue) System voltage level 0 ~ 440 V AC (Um) Mains fail voltage 75 ~ 5% Ue (Tf) Mains fail delay 0.5 ~ 8.0 sec. (Tr) Mains return delay 5 ~ 00 sec. (Tg) Generator cool down time 30 ~ 00 sec. Dimensions (W) 5 mm, (H) 43 mm, (D) 38 mm Power supply 4V DC 5% Maximum ripple An optional UPS backup supply is available for this unit. It contains rechargeable batteries which can supply enough power to energise a shunt trip and keep the unit powered for up to hour. Refer to page 45 for details. 4

8 Memshield - ACB Accessories for Draw-out Type Memshield Main circuit safety shutters Position switches When the breaker is drawn out the shutters automatically conceal and insulate the main circuit disconnect contacts on the cradle. Each shutter can be padlocked in the closed position. For safety during inspection and maintenance, up to three padlocks may be applied to each of the top and bottom shutters (padlocks not supplied). The top shutter and bottom shutter can be opened or closed independently by manual operation. Maintenance can be done in the open position. (The mechanism is released automatically by inserting the circuit breaker). The top shutter and bottom shutter can both be moved individually. The Position switches operate when the breaker is in CONNECTED position, TEST position, ISOLATED position or in the INSERT position, to electrically indicate the breaker position. These switches are divided into units () and () as shown below, and one switch can be selected from each unit. A max of units can be fitted on ACBs MACB06~0, 3 Pole. A max of 4 units fitted on any other ACB size. UNITS () UNITS () () CONNECTED () ISOLATED position position, indicator indicator switches switches ( max) ( max) () TEST position, () INSERT position, indicator switches indicator switches ( max) ( max) (3) CONNECTED (3) ISOLATED and and TEST position. INSERT position, indicator switches indicator switches (one each) (one each) TEST JUMPER The test jumper allows open-close tests on the removed breaker (The standard length of the cable is 5m) Position switch, operating sequence Connected position indicator switch Test position indicator switch Isolated position indicator switch Insert position indicator switch (Isolated) (Test) a-contacts "ON" Position switch ratings a-contacts "ON" (Connected) a-contacts "ON" a-contacts "ON" Load Resistive Lamp Inductive Motor AC50V 0A.5A 6A A DC30V 6A 3A 6A 3A DC5V 0.6A 0.A 0.6A 0.A DC50V 0.3A 0.05A 0.3A 0.05A MAL-INSERTION PREVENTION DEVICE Interchangeability exists within the Memshield range of. Because of this feature there is a possibility for a breaker of a different specification being placed into the cradle. This is effectively prevented by the use of the Mal-insertion Device. CONTROL CIRCUIT SAFETY SHUTTER The control circuit disconnect contacts have independent shutters for increased safety. They are not padlockable. BREAKER FIXING BLOCKS These provide reinforcement for the breaker mounting where vibration occurs. They are always fitted when the breaker is subject to marine classification society rules. DRAW-OUT POSITION PADLOCK The breaker can be padlocked in three positions, CONNECTED, TEST and ISOLATED. The padlocking device is fitted as standard. Padlocks not supplied (hasp diameter 8 or 6mm). 5

9 Memshield Memshield ACB - Spring Charged Operation Manual charging type Rating of motor charging type The closing springs are manually charged by pumping the charging handle. When the PUSH TO CLOSE button is pressed, the closing springs are released, quickly closing the breaker. (An electrical latch release can be provided for remote closing applications. The closing springs must be charged manually prior to remote close operation). Motor charging type The motor automatically charges the closing springs. The latch release coil is energised by a remote push button, releasing the springs and quickly closing the circuit breaker. With the breaker closed, the motor automatically starts to charge the springs again for the next closing operation. Manual charging is also possible. Separate charging and closing circuits are available on request. Breaker Rated voltage Min & max Inrush Steady-State Charging Closing List No operation current current time command voltage (peak value) (AC, A, current r.m.s. value) (peak value) MACB06 MACB MACB6 MACB0 MACB5 (V) (V) (A) (A) (S) (A) AC (40V) (40V) AC (0V) (0V) AC (0V) (0V) DC (0V) (0V) DC (5V) (5V) DC (00V) (00V) DC (48V) (48V) DC (4V) (4V) AC (40V) (40V) AC (0V) (0V) AC (0V) (0V) DC (0V) (0V) DC (5V) (5V) DC (00V) (00V) DC (48V) (48V) DC (4V) (4V) MACB3 MACB40 AC (40V) (40V) AC (0V) (0V) AC (0V) (0V) DC (0V) (0V) DC (5V) (5V) DC (00V) (00V) DC (48V) (48V) DC (4V) (4V) Motor charging and closing operation CHARGING OF CLOSING SPRINGS When the closing springs are DISCHARGED, the spring charged switch in series with the motor is closed. Control voltage is applied to terminals and and the motor starts to charge the springs. When the closing springs are fully charged, the spring charged switch in series with the motor opens and cuts the supply to the motor. *CLOSING THE ACB *ANTI-PUMPING FUNCTION 3 * Refers to standard circuit 3 When the springs are charged, the spring charged ON switch in series with the LRC is closed. Apply voltage across terminals 3 and, through PB (close). The latch release coil (LRC) is energized and the closing springs are released to close the ACB. Open the spring charged ON SW. by releasing the closing spring and cuts the supply to the LRC by AUX SW. b-contact. Once the closing springs have been released, the spring discharged switch is closed. If a close signal is continually applied across terminals and 3, the holding relay (HC) is energized and self holds when the HC a-contact closes. The HC b-contact opens, cutting the supply to the LRC. ACB can not re-close without opening the PB (close). 6

10 Memshield ACB - Spring Charged Operation Memshield Motor circuit Source Ry Ry etc For spring charge indication Interlock switch PB (Close) Source for motor Ry Ry etc For spring charge indication Interlock switch PB (Close) Source for L.R.C R AXT-C Spring charged switch C C HC R AXT-C Spring charged switch C C HC M B 04 B AMT-C 05 R HC D D D A 4 M AMT-C B B R HC D D D A 4 AXT-C 0 Spring charged switch ON LRC AXT-BA 03 Aux.Sw. 4 AXT-C Spring charged switch AXT-C 0 Spring charged switch ON LRC AXT-BA 03 4 Aux.Sw. AXT-C Spring charged switch Standard circuit 4 Split supply circuit 4 Power transformer (external) The maximum rated control power voltage applicable to the motor charging type is 50V AC. If a higher voltage than this value is applied, a power transformer is required. MEM Ltd. (500V) can offer the following transformers. (please specify on order). AUTOMATIC CLOSING SPRING RELEASE Rated Transformer Control Voltage Type Cap. Volt ratio AC350-35V TSE -30M 300VA 380 / 0V AC40-470V TSE -30M 300VA 450 / 0V SPRING CHARGED SWITCH JIG FOR SLOW-CLOSING The closing springs are automatically released when the breaker is drawn out from the TEST position to the ISOLATED position. This switch electrically indicates the charged condition of the closing springs. Ratings Resistive Motor AC5V-50V 7A 4A DC5V-50V 0.4A 0.05A Jigs can be supplied with the breaker for inspection and maintenance purposes (they are required when changing the arcing contacts of the ACB). Slow-closing operation can be made by the charging handle when the slow-close jigs are installed. 7

11 4 Memshield Memshield ACB - Electrical Tripping Devices Shunt trip (SHT) The shunt trip device allows the ACB to be remotely opened. Instantaneous operating and continuously rated versions are available. (Contact MEM Ltd. (500V) for details of continuous rated type). Memshield ACB can be fitted with shunt trip and UVT. Shunt Trip Ratings (instantaneous operating type) Shunt Trip Rated Voltage Operational Voltage Peak Excitation Opening Time Current (max) (V) (V) (A) (ms) AVT- AC (450V) 30 AC (380V) 30 AC (0V) 30 AC (0V) 30 DC (0V) 30 DC (00V) 30 DC (48V) 30 DC (4V) 30 Capacitor trip Combined with the shunt trip device, the capacitance trip device enables the ACB to be remotely tripped after a voltage (ac) drop due to a power failure, short circuit, etc, provided that the remote trip operation occurs within 30 seconds after the voltage drop. Type AQT-A AQT-B Rated Voltage AC 00-0V 0~40V Operational Voltage 70 to 0% 70-0% Rated frequency 50/60Hz 50/60Hz Rated Voltage of Shunt Trip used DC0-5V DC50~30 Power Consumption (Inrush) 00VA 00VA Outline Dimensions (mm) SWITCH RED NEON 4.0 ON 3 INPUT CAPACITOR CHARGE OUTPUT CAPACITOR TRIP DEVICE 4 - ø4.5 CSK mtg. holes FRONT VIEW SIDE VIEW Control Circuit Power Source 8 SHT ACB AUX SW 7 PB (OPEN) or OCR etc ON R C NL Power Switch Di Di R Di 8

12 Memshield Memshield Overcurrent Protection Relay (AORB) Multi-function Protection Device Protection functions Adjustable Long Time-delay LTD. The LTD function protects against overload. Select HOT or COLD start. The HOT start characteristic takes account of accumulated heating caused by previous loads. Adjustable Short Time-delay STD The STD function is intended to give discrimination with other devices during short circuits. The STD characteristic is user-selectable between 'definite timedelay' and 'I t ramp' characteristics. (HOT start characteristics are not The 'definite time-delay' is suitable for available on M type) co-ordination with other definite time delay devices. The 'ramp' characteristic allows closer co-ordination with thermal-magnetic MCCBs. When the STD is set to 'I t ON', the 'ramp' characteristic is in operation up to 000% of the base Pick-up current of LTD current for L & M (general feeder protection) type OCRs and up to 500% for S (generator protection) type OCRs. time Above these levels the definite time-delay Fluctuating current load profile comes into operation. The STD is set to 'I t ' at the time of manufacture. current tripping time tripping time time Conventional electronic relay without thermal memory time Microprocessor based relay with thermal memory. Simulates true heating effect of conductor. 3 Adjustable Instantaneous Trip INST. The INST. function protects against short circuits, without a built-in time-delay, It is user-selectable between 'INST.' or 'MCR'. The MCR (Making Current Release) function operates only during the closing cycle of the ACB and is disabled once the ACB has fully closed. 4 Adjustable Pre-Trip Alarm PRE-TRIP The PRE-TRIP alarm gives warning (via a voltage free contact) of impending trip due to overload. On L and M type OCRs, it has a definite time delay and on S type OCRs, it has an inverse time delay. PRE-TRIP signal automatically resets when the current drops below pick-up current (IP). 5 Adjustable Ground Fault GFT The GFT pick-up current can be set between 0% to 40% of the CT rated primary current and the definite time delay between 80 to 000ms. 6 Neutral Phase Protection N-phase Available on 3 & 4 pole ACBs for use on 3-phase, 4 wire systems. The N-phase current setting is 0% to 00% of the CT rated primary current. Please specify at time of ordering. 7 OCR Sealing Facility Unauthorised access to the OCR adjustment dials can be prevented by use of an optional sealing cover. This is placed over the dials and secured by two screws. The screw heads have holes drilled in them for a sealing wire to be fitted. (Wire and seal are not provided). NON setting and FAIL-SAFE Each of the overcurrent protection functions (LTD, STD, INST/MCR) can be disabled by setting the respective pick up dial to 'NON' position. (For example, the INST setting is often set to 'NON' to improve selectivity levels.) If the STD and INST functions are both set to 'NON' (thereby removing all short-circuit protection), the in-built FAIL-SAFE function will trip the ACB on fault currents exceeding 6 times the base current [I0], instantaneously. 3 If the STD and MCR functions are both set to 'NON', the in-built FAIL-SAFE function will trip the ACB on fault currents exceeding 0 times the base current, [I0], (on L and M type OCRs) and 5 times the base current, [I0] (on S type OCRs). Trip time is the STD time setting. Base current [Io] The base current, [I0], is used as the reference for deciding the current and time settings of the LTD, STD, INST. and PRE-TRIP functions. On AOR-BL and AOR-BM type OCRs, it can be set by means of a dial on the front to 50, 63, 80 or 00%, of the rated CT primary current (ICT). On AOR-BS, it is factory set according to the full load current of the generator (which should be specified at time of order). Base current selection procedures are as follows: (Refer to tables on P.4, 6, 8 for available values of [ICT] and [I0]. For General Feeder Circuits For Generator Protection Calculate the maximum full load current, [ILOAD], through the ACB. Check the generator full load current, [IGEN]. Select the required rated primary current, The base current, [I0], will be equal to [ICT], of the OCR, (note that [ILOAD] must [IGEN] and should be used as a reference not be greater than [ICT]. for the pick-up current settings of the 3 Decide what the base current, [I0] should other protection characteristics. be and use this as a reference for the LTD, 3 Select the OCR with the protection and STD, INST and PRE-TRIP current settings. indication functions required for the 4 Select the OCR with the protection and particular application. indication functions required for the particular application. Note: The ground fault pick-up current, [IG] is a factor of [ICT], not [I0]. 0