Page 1 of 12 RESEARCH DESIGN & STANDARDS ORGANISATION MINISTRY OF RAILWAY POWER SUPPLY & EMU DIRECTORATE TITLE SPECIFICATION FOR VANE TYPE AIR FLOW RELAY FOR ROOF MOUNTED AC PACKAGE UNIT S.No. Date of amendment Revision APPROVED EDPS
Page 2 of 12 Government of India Ministry of Railways Research Designs & Standards Organisation Manak Nagar, Lucknow 226011 SPECIFICATION FOR VANE TYPE AIR FLOW RELAY FOR ROOF MOUNTED AC PACKAGE UNIT 0.0 FOREWARD 0.1 At present vane type air flow relay are being used in RMPU to supervise the correct operation of blower provided in RMPU to ensure the air flow through evaporator coil and heaters. Zonal Railways have complained that present design for vane relays is not having sufficient mechanical strength resulting the breakage of flapper lever provided for operating the microswitch. RDSO has prepared this specification to overcome the existing defects as well as to standardise their design to be used by all the suppliers. This specification will supersedes the earlier design of vane relay as per RDSO drawing No. SKEL-4428 and its mounting arrangement will remain as per RDSO drawing No. SKEL 4429. 1.0 SCOPE 1.1 This specification covers the design parameters and testing requirements of vane type air flow relays for use in RMPU s. 1.1 The vane type airflow relay is to be provided in Roof Mounted AC Package Unit. The contacts of the relay will open or close the appropriate/respective circuit as shown in RDSO drawing No. SKEL-4391. 1.2 The vane type airflow relay shall be mounted at both the return air entry/ path of RMPU. 1.3 The coil of the auxiliary contractors in heating and cooling circuit shall be energised through this vane relay.
Page 3 of 12 2.0 TERMINOLOGY 2.1 The following definitions shall be applied in this specification. 2.1.1 Pickup speed : The air velocity in meters per second required to make the electrical contact close. 2.1.2 Dropout speed : The air velocity in meters per second required to make the electrical contact open. 2.1.3 A single pole micro switch will have three terminals (contacts) with one NO, one NC and third used as common. 3.0 SERVICE CONDITION 3.1 Environmental conditions : Maximum ambient air temp : 57 deg.c. Average ambient air temp. : 35 Deg. C. Maximum relative humidity : 100% Atmosphere : Coastal area : Extremely dusty and desert weather and desert terrain in certain areas. The dust content in air may reach as high values as 1.6 mg/m³. The equipment shall be designed to work in coastal areas in humid, salt laden and corrosive atmosphere. The maximum value of the
Page 4 of 12 condition will be as under ; Max. PH Value 8.5 Sulphate 7 mg/litre Max Concentration 6 mg/litre of chlorine Max. conductivity 130 micro- Semen/CM Annual rainfall : Altitudes : Ranging Between 1750 to 6250 mm Not exceeding 1200 m 4.0 RATING Microswitch Rating Rated Voltage Normal operating voltage range Current rating 250 V AC 90-125 V AC 15 Amp. 4.1 Vibration and shocks : The vane type air flow relay shall withstand satisfactory vibrations and shock normally encountered in service as indicated blow:- (a) Maximum vertical acceleration - 1.0 g (b) Maximum lateral acceleration - 0.5 g. (c ) Maximum longitudinal acceleration - 3.0 g. ( g being the value of acceleration due to gravity)
Page 5 of 12 The vibrations are of sine wave from and frequency of vibrations is between 1 Hz and 50 Hz. The amplitude a expressed in mm is given as a function of f by a=25/f for value of f from 1 to 10 Hz. And a=250/f²for the value of F exceeding 10 Hz. And upto 50 Hz. 5.0 GENERAL DESIGN ASPECT 5.1 Electrical requirement 5.1.1 The contact of the relay shall close or open to energise or de-energise the coil of auxiliary contactor provided to connect or disconnect the supply of the cooling and heating circuit through it s auxiliary contact as shown in RDSO drawing NoSKEL-4391 of RDSO Specification for AC Control Panel for RM PU no. ELPS/ SPEC/ AC/ 04 ( Rev. 2) Of Aug. 99. 5.1.2 The circuit shall be active at an air velocity of 5 meter per second and should be inactive when the velocity falls below 2 meter per second. 5.1.3 The design of the vane type air relay shall be in such a way that under normal condition, the contact of the micro-switch remain open and shall be closed under air pressure. 5.1.4 The opening and closing of contact of the micro-switch shall not be accompanied by any rebound. 5.1.5 The relay shall be designed so as to avoid the contact chattering, bounce and hesitation. 5.1.6 The terminal of the micro-switch shall be accessible for external connection. The connection shall be made from the rear by means of crimped lug over PTFE wire. 5.1.7 The clearance and creepage distance shall be as per IS: 4237 of latest version.
Page 6 of 12 5.2 Mechanical Requirements 5.2.1 The relay shall be so designed and constructed that it will withstand, vibrations and shock encountered during service as specified in clause 4.1 of this specification. 5.2.2 The housing assembly and the attachment of flap shall generally confirmed to the RDSO drawing No. RDSO/PE/SK/AC/0039 (Rev. 0 ) enclosed with this specification. 5.2.3 Sharp edges and sharp corners shall be made blunt. 5.2.4 The flap design will be as per RDSO drg. No.RDSO/PE/SK/AC/0040 (Rev. 0 ) enclosed with this specification. 5.2.5 The housing assembly and the flap shall be made of corrosion resistance grade 304 of Stainless Steel having thickness not less than 18 SWG and 32 SWG respectively. 5.2.6 The general arrangement for mounting the vane type air flow relay is shown in RDSO drawing No. SKEL 4429 of Specification for RMPU, no. ELPS/ SPEC/ AC/ 03 ( Rev. 1) Of Aug. 99 with suitable provision for fixing the relay assembly. 5.2.7 Minor modification in the mounting bracket for vane relay as shown in RDSO Drg. No. SKEL4429 may be done with prior approval of RDSO to suit the housing assembly. 5.2.7 Screws, nut & bolts used in manufacturing the same shall confirm to IS:1364 (Pt. 1 to 5). 5.2.8 The freely movement of the flap shall be ensured. 5.2.9 The general workmanship & welding quality shall be of high quality. 6. MARKING 6.1 Each vane type air flow relay shall be marked the following information : 1) Manufacturer s name or trade mark, if any
Page 7 of 12 2) Make and rating of Micro-switch 6.2 The information mentioned in clause 6.1 shall be screen printed in white color on black ground for easy identification on aluminum plate and shall be riveted on the side wall of the housing. 6.3 The manufacturer shall supply the design drawings, technical detail of the microswitch, maintenance instruction (schedule + trouble shooting) and internal test report to the purchaser with the first batch of the supply. 7. TESTS 7.1 Type test : After the approval of drawings from RDSO, the manufacturer shall develop a prototype of the Vane type airflow relay and shall offer the same alongewith their internal test report to RDSO for type test. The following test shall be conducted on prototype at firms premises as type test: 1. Physical inspection and dimensional checks 2. Performance t est 3. Mechanical endurance test 4. Electrical endurance test 5. Insulation resistance test 6. Vibration and shunting shocks test 7. Contact resistance test 8. Di-electric test 7.2 Routine test : The following tests shall be conducted on series production on each vane type airflow relay by the manufacturer at their premises: 1. Physical inspection and dimensional checks
Page 8 of 12 2. Performance Test 3. Insulat ion resistance test 4. Di-electric test 7.3 Acceptance test: For accepting a lot of vane type airflow, the following test on sample basis shall be conducted at firm s premises: 1. Physical inspection and dimensional checks 2. Performance Test 3. Insulation resistance test For accepting the lot of vane type airflow relay, the samples for acceptance tests shall be chosen at random 5% (Minimum 2 pieces) of the lot offered. 8. TEST DETAILS AND PROCEDURE 8.1 Physical inspection and dimensional checks The vane type airflow relay housing, flaps and other part of the assembly shall be examined for its dimensions and workmanship. The tightening of bolts and fixation of various components to be also checked. The general workmanship should be good with all the component properly secured and sharp edges rounded off. 8.2 Performance Test (Pickup and dropout speed) Relay assembly including flap shall be fitted in an air duct specially made for testing. Anemometer to measure the air velocity shall be
Page 9 of 12 installed in the circuit. The pick up and dropout speed will be measured by gradually increasing and decreasing the air velocity. Maximum pick up speed should be 5meter per second and minimum drop out speed should be 2 meter per second. 4.3 Di-electric Test The dielectric test shall be conducted as per IEC 571-1 for supply voltage range between 72 V and 125 V with rms value of test voltage as 1500 V. 4.4 Insulation Resistance Test The insulation resistance of the unit between earth and current carrying parts shorted together shall be more than 10 mega ohm at a ambient temperature of 55 degree C measured with 500 V megger. 4.5 Electrical endurance test The Electrical & Mechanical endurance after successful completion of vibration and shock test. The complete relay assembly shall be subjected to 50,000-make and break operation with 3A inductive load at 110 V AC. The frequency of operation shall be 6 per minute with 5 sec. on and off periods each. At the completion of the test, the relay contacts shall be visually examined for any damages, making it unsuitable for use. 4.6 Mechanical endurance test The complete relay assembly shall be subjected to 1,00,000 operations (closing and opening) at the rate of one operation in two seconds. The operational values such as pick up and drop out speed and contact resistance shall be recorded before commencement of the test and
Page 10 of 12 subsequently after every 50,000 operations at the end of the test. The variation in operating values shall not exceed +/- 10 percent of the specified values after 1,00,000 operations. There should not be any physical deterioration making it unsuitable for use. Mechanical & Electrical endurance tests will be conducted on separate relays. 4.7 Test for withstanding vibration and shock Vibration and shock test to be conducted as per clause 2.1.3 and 5.10 of IEC-571-1 at 3g. After the test the performance and visual test to be repeated. 4.8 Contact resistance measurements : Contact resistance values of the contacts in closed position shall be recorded as per IEC 512 (Pt.2) before and after the electrical and mechanical endurance test. Before the test the contact resistance should not be more than 10 milli ohm and after the test it should not deteriote by more than 10%.. 9.0 PROTOTYPE APPROVAL 9.1 Manufacturers shall obtain prior approval of Research Designs and Standards Organisation for each production model. He should submit the sample alongwith assembly and part drawings, copies of the reports of prototype carried by the manufacturer for inspection and approval. 9.2 The manufacturer shall submit clause by clause compliance of the specification. 10.0 TECHNICAL DOCUMENTS & MANUALS The manufacturer shall furnish with each order a prototype test data obtained on the batch under supply and a test certificate for each relay confirming that the relay has passed the routine tests at the manufacturer s works. Manufacturer shall also supply sufficient copies of maintenance instructions and spare parts lists.
Page 11 of 12 11.0 TESTING FACILITIES The venue of testing shall be indicated by the purchaser. If the purchaser chooses the manufacturer s works as the place of testing, the latter shall provide personnel, equipment and premises for conducting the tests, free of charge. **********
Page 12 of 12 DISTRIBUTION: 1 CEE / Eastern Railway, Fairlie Place, Kolkata 2 CEE / Northern Railway, Baroda House, New Delhi 3 CEE / Central Railway, Mumbai CST 4 CEE / Northeast Frontier Railway, Maligaon, Guwahati 5 CEE / North Eastern Railway, Gorakhpur 6 CEE / South Central Railway, Secunderabad 7 CEE / Southern Railway, Park Town, Chennai 8 CEE / South Eastern Railway, Kolkata 9 CEE / Western Railway, Churchgate, Mumabi 10 CEE / North Central Railway, Hasting Road, Allahabad 11 CEE / Western Central Railway, Jabalpur 12 CEE / Integral Coach Factory, Chennai. 13 CEE / East Coast Railway, Bhuvneshwar 14 CEE / East Central Railway, Hajipur 15 CEE/ Rail Coach Factory, Kapurthala 16 CEE./ North Western Railway, Jaipur 17 Director / IRIEEN, Nasik Road 18 Director / CAMTECH, Gwalior 19 Secy.(Elec.) Railway Board, New Delhi 20 DDSE/DOC. 21 ADE-9 22 Unit Supervisor