Current Balance Relays WILMAR™ Protective Relays – WCB Series Function: 60 or 87 • ANSI/IEEE C37.90-1978 TERMINAL STRIPS #6 - 32 SCREWS • UL file No. E58048 • CSA file No. LR61158 Current Balance Relays are designed to sense unbalanced current flow in a three phase system. The primary application of Current Balance Relays is to protect three phase motors against phase unbalance or phase failure. Operation: 3 1/2 With control voltage applied to the relay, the output contacts will energize when the three phase currents are balanced (including zero currents), and will be de-energize by unbalance currents. 1 /4 4 5.0 1 /2 5 4.0 5.0 13/ 64" DIA. 4 MTG. HOLES PART NUMBER SELECTION Note: Dimensions in inches. Multiply values by 25.4 for dimensions in mm. PRODUCT SPECIFICATIONS Part Number WCB Series Line Current ..................................... Three Phase, AC current, 50-400 Hz Direct or from CT. 5 amp continuously 20 amp, 30 sec. 200 amp, 0.10 sec. Control Voltage ................................ See Part Number Selection Unbalanced Trip Point ..................... Screwdriver adjustable. Adjustment range in accordance with ordering information. (The unbalanced value is defined as the difference between the highest and the lowest phase current). Drop-Out Time Delay ....................... 0.9 to 1.3 seconds Surge Withstand Capabiliy .............. In compliance with C37.90B ANSI/IEEE Operating Temperature .................... -40oC to +70oC PART NUMBER SELECTION Sample Part No. WCB-120AC-1-A Type: WCB = Current Balance Control Voltage (± 15%) 26 DC 48 DC 125 AC 120 AC 230 AC 380 AC 460 AC Trip Adjustment Range .5 = 0.1 amp to 0.5 amps 1 = 0.2 amp to 1 amp 2 = 0.4 amp to 2 amp Options: A = two normally open contacts B = two normally closed contacts Burden .............................................. Current input: 5.0 VA, Phase Control voltage: 3.0 VA Contact Ratings ................................ One set, N.O., One set N.C. 5 amp resistive at 120 VAC or 28 VDC Notes: 1. Remove black screw for access to the trip adjustment. 2. Clockwise rotation of the adjustment potentiometer will raise the unbalance trip point. 3. The output contacts are shown de-energized. 32 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)