WCD

Current Differential Relay WILMAR™ Protective Relays – WCD Series Function: 87 • ANSI/IEEE C37.90-1978 TERMINAL STRIPS #6 - 32 SCREWS Current Differential Relays are used for the protection of transformers, motors and generators, by comparing the magnitude of the current entering and leaving the protected circuit. On a given phase winding, any difference between the two currents will indicate an internal fault; the relay will sense the vectorial difference between the two currents of the protected section and will initiate a quick disconnection of the unit, to prevent disastrous consequences. The relay may also be used to protect internal faults on transformers, such as: ground faults, shorted winding, leakage between primary and secondary, etc. It will sense and compare primary vs. secondary currents, once the turns ratio has been taken into consideration. 3 4 3 7 /8 4 1 /2 Note: Dimensions in inches. Multiply values by 25.4 for dimensions in mm. 4 7 /8 4 5 /8 Operation: With control voltage applied, the output contacts (shown in the de-energized position) will remain deenergized as long as the difference between the two input currents remains below the preset trip value. The contact will transfer to the engerized position when the current difference exceeds the trip value. PART NUMBER SELECTION .172 DIA. 4 MTG. HOLES PART NUMBER SELECTION PRODUCT SPECIFICATIONS Sample Part No. WCD-230AC-1-A Type: WCD - Close Differential Control Voltage VAC & VDC 120AC 25DC 208AC 48DC 230AC 125DC 380AC 416AC 460AC 525AC 575AC Trip Adjustment Range .5 = 0.1 amp to 0.5 amp 1 = 0.2 amp to 1.0 amp 2 = 0.4 amp to 2.0 amp Options A = Two normally open contacts B = Two normally closed contacts H = Contacts rated 3 amp at 125 VDC P = Transient protection is provided in compliance with ANSI/IEEE C37.90-1978 Consult factory for additional models. Part Number WCD Series Line Current ..................................... Single Phase, AC current, 50-400 Hz Direct or from CT 5 amp continuously 20 amp 30 seconds 200 amp, 0.10 seconds Control Voltage ................................ See Part Number Selection Differential Trip Point ....................... Screwdriver adjustable. See Part Number Selection Operating Temperature .................... -40oC to +75oC Burden .............................................. Current input: 2.5 VA max. Control voltage DC: 2 W max. AC: 2 VA max. Output Contacts ............................... One set, N.O., One set N..C. Contact Ratings ................................ 5 amp resistive at 120 VAC or 28 VDC Notes: 1. Remove black screws for access to the trip adjustments. 2. Clockwise rotation of the adjustment potentiometer will raise the current differential trip point. 3. The output contacts are shown de-energized. Tyco Electronics / www.tycoelectronics.com / Factory Direct Technical Support: 800-253-4560, ext. 2023 (U.S., Canada, Mexico) or 805-220-2020, ext. 2023 (International) 35