Current Balance Relays
WILMAR™ Protective Relays – WCB Series
TERMINAL STRIPS
#6 - 32 SCREWS
Function:
60 or 87
•
ANSI/IEEE C37.90-1978
•
UL file No. E58048
•
CSA file No. LR61158
Current Balance Relays are designed to sense un-
balanced current flow in a three phase system. The
primary application of Current Balance Relays is to
protect three phase motors against phase unbal-
ance or phase failure.
Operation:
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.
3
1
/
2
Note:
Dimensions in inches. Multiply values by 25.4 for dimensions in mm.
Part Number
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 .................... -40
o
C to +70
o
C
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)
4
1
/
4
5.0
1
/
2
5
4.0
5.0
13 64
"
/
DIA.
PART NUMBER SELECTION
4 MTG. HOLES
PRODUCT SPECIFICATIONS
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
WCB Series
