Sm-4522a

Transcript

WRBCC ~ ~ SERVICE SPECIFICATION SU-4522-A ~ ORP-66 PLUG-IN D. C. SWITCH OVERLOAD RELAY I. GENERAL The ORP-66 D. C. switch overload relay is furnished primarily for the overload protection of high voltage D. C. switch machines having split-field motors. This relay can be used also to protect low voltage D. C. switch machines with split-field motors under the same current conditions. This relay, with a different thermal resistor, can be furnished to match a motor with another D. c. current range. The ORP-66 relay covered by Service Specification SU-4522 is for use with A.C. switch machines. It has a built-in rectifier, an operating relay and a stick relay. The ORP-66 D. c. overload relay covered by this specification (SU-4522-A) has no rectifier but does have an operating relay and a stick relay. The operating relay coil, paralleled by a thermal resistor, is in series with the motor. When the motor current becomes excessive, the operating relay picks up. This picks up the stick relay which then releases the operating relay and deenergizes the switch control relay, thereby opening the motor control circuit. The thermal resistor has a high temperature coefficient of resistance so that with excessive motor current its resistance will increase giving a longer cut-out time for a lower current and a shorter cut-out time for a higher excessive motor current. II. ADJUSTMENT AND CALIBRATION 1. Operating Relay o. 007 a. The air gap between the armature and the core should be between to o. 010 inch. b. The armature stroke at the free end of the armature insulation should be O. 128 ± o. 003 inch. UNION SWITCH & SIGNAL DIVISION PRINTED IN U.S.A. AO. 65-300-1045. I Westinghouse Air Brake Company PITISBURGH, PA. 15218 Oct. 1965 2. c. The two load springs should be adjusted to exert a pressure of approximately 7 grams each on the armature in the deenergized position. This pressure may be changed as required to meet relay calibration values. d. The heel spring should exert a pressure of approximately 13 grams against the armature in the deenergized position. e. The front contact spring should have an initial pressure of approximately 10 grams against its stop, measured at the contact tips, and should have an opening of approximately O. 070 inch with the relay deenergized. Stick Relay a. The air gap between the armature and the core should be approxi mately O. 004 inch. b,_ , The armature stroke at the free end of the armature insulation should be O. 080 ± O. 002 inch. c. The continuity contact should be adjusted as follows: (1) The front contact (lower) spring should be adjusted to exert a pressure of from 10 to 15 grams on the armature in the deenergized position. (2) The opening between the front contact and the heel (upper) spring should be from O. 020 to O. 025 inch with the armature in the deenergized position. At the same time the heel spring pressure .should be adjusted so that the back contact tip just touches-its lower stop and the upper stop should be adjusted to just touch the heel spring. (3) Adjust the back contact opening to be from O. 015 to O. 020 inch with the armature in the energized position. This should be done by bending the loop at the end of the back contact spring. (4) Adjust the back contact spring to exert an upward force of from 20 to 25 grams against the lower stop with the armature in the energized position. Recheck the heel spring pressure. (5) With the armature in the energized position and all adjustments completed, the opening between the back contact buttons and the lower stop is an approximate measure of the mid-stroke overlap of the contacts. This should be at least o. 010 inch. 3. Preliminary Calibration The Operating and Stick relays should be individually calibrated to meet the limits given in Table 1. With the relays disconnected, this is no problem. If the relays are wired, they can be calibrated by temporarily opening the thermal resistor circuit at one terminal and testing in a circuit as shown in Figure 1. SU-4522-A, p. 2 WABCO "V" . "V" . NOTE: WHEN CALIBRATING THE STICK RELAY THE OPERATING RELAY ARMATURE MUST BE PICKED-UP MANUALLY TO CLOSE FRONT CONTACT REAR VIEW ORP-66 RELAY MOUNTING BASE (HV+) (HV-) OPER S.P.D:r. SWITCH + STICK (DC +)(DC-)(W) v Figure I. Circuit for Preliminary Calibration The load springs and front contact heel of the Operating relay and the front contact spring of the Stick relay may be given a slight readjustment of their pressures if necessary to meet the specified pick-up values. 4. a. Drop-Away - Each Style "L" relay shall be given a charge of four times the pick-up value and the current then gradually reduced until the armature drops away, opening the front contact. b. Pick-Up and Working - After the drop-away reading, the energizing circuit shall be opened for one second and then current of the same polarity applied again, and gradually increased until the armature is attracted and the front contact made. This is the Pick-Up and Working value, and at this energization the armature shall move to the full stroke position. c. The air gap between the end of the core and the Operating relay armature should not be reduced below o. 004 inch. Internal Wiring The internal wiring should be as shown in Figure 2. SU-4522-A, p. 3 WABCO V""~ THERMAL RESISTOR O HV- ::) m RELAY BR. A 11 1 R. BK. G. w BU. DC- BR. DC+ Figure 2. Wiring, Facing the Front of the Relay 5. Final Calibration This is a test of the complete overload relay including the thermal resistor connected across the operating relay coil. Final calibration should be made with the relay cover applied so as to give normal functioning of the thermal resistor. After a given test the thermal resistor must be permitted to cool before the test is repeated. Test the relay in a circuit-in accordance with Figure 3. Set resistor R-2 to provide 0. 013 ampere to pick-up stick relay. Close momentarily switch S to position 1 to pick-up the ANL-30 relay, which will be held energized over its own front contact. Then throw switch S to the position 2 to energize overload relay. By adjusting R-1, set the "overload" current at the value specified in Table 2. At this current value the operating relay should pick-up within 10% of the time value specified in Table 2. A small adjustment of the operating time can be obtained by reducing or increasing the distance between the turns of the thermal resistor. SU-4522-A, p. 4 WABCO "V'°.A."V" REAR VIEW OF ORP-66 I HV+- -HV-:- RELAY MOUNTING BASE I I DC- A w l:::::J I - _J II OPERATE" D.C.AMMETER s 2 R-1 +___~,, ... - -fil 1----10 TO 12 V.D.C. ANL-30 RELAY _ _..., UN 143739 10 NOTE: R-1 RESISTOR MUST BE CAPABLE OF CARRYING 20 AMPS INTERMITTENTLY R-2 RESISTOR IS TO ADJUST CURRENT TO 0.013 AMPS. v. I IO V.A.C. Figure 3. Final Calibration When the operating relay picks up, it energizes and picks up the stick relay which releases the ANL-30 relay and sticks itself up. (ANL-30 release interrupts the overload current to the operate relay which thus drops out. ) Successive tests of operating time must be made. Allow sufficient time for the thermal resistor to return to room temperature between tests. SU-4522-A, p. 5 6. Cover Assembly Apply the cover as outlined in Service Specification SU-3166. rz::. Service Recommendations Relays should be checked periodically in service to assure that they give the desired delay times. This may be done by obstructing the switch points, measuring the current at which the clutch slips and noting the time it takes for the relay to function. For accurate measurement of time for the relay to operate, about 2 minutes should be allowed for the thermal resistor to cool. In no case should another operation be tried with less than 6 seconds cooling time or the relay may not have sufficient motor surge current protection. When adjusting or working on a switch machine, apply a jumper between terminals HV+ and HV- to shunt out the thermal resistor. Of course, the jumper must be removed for normal circuit functioning. :~ ~ Switch machine clutch slippage should be maintained at approximately 13 amperes. If the clutch slippage current is excessively low, the overload relay will not function and might be damaged. TABLE 1 PRELIMINARY CALIBRATION VALUES Relay Operating, UN291230 Stick, UN291231 Ohms Min. Drop Away 5.0 o. 20 v. o. 90 v. 750.0 Pick-Up and Working Min. Max. 0.95 v. 1. 0 v. 8. 0 v. TABLE 2 FINAL CALIBRATION VALUES Relay Pc. No. UN397498 or UN397498-001 SU-4522-A, p. 6 Thermal Resistor Pc. No. Norn. Ohms UN392596 0.046 Operatin~Time @Amps Sec. Amps Sec. 13 5 15 3