WVM911RN-60 - WVM Series

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Littelfuse Voltage Monitoring Relays
The WVM Series provides protection against premature equipment (motor) failure caused by voltage faults on the 3-phase line. The WVM’s microcontroller design provides reliable protection even if regenerated voltages are present. It combines dependable fault sensing with a 10 fault memory and a 6 LED status display. Part instrument, part control, the WVM protects your equipment when you’re not there and displays what happened when you return. The WVM is fully adjustable and includes time delays to prevent nuisance tripping and improve system operation. Time delays include a 0.25 to 30s adjustable trip delay, an adjustable 0.25 to 64m (in 3 ranges) restart delay, plus a unique 3 to 15s true random start delay. The random start delay prevents voltage sags caused by simultaneous restarting of numerous motor loads after a power outage.


See datasheet for operation details.

Property (Mouseover for details) Value
Input Voltage (V) 400 to 480VAC
Input Type 3-phase delta or wye with no connection to neutral
Input AC Line Frequency (Hz) 50/60Hz
Output Type Electromechanical relay
Output Form Isolated SPDT
Output Load Rating (VA) 10A resistive @ 250VAC; 6A inductive (0.4pF) @ 250VAC
Response Time (ms) Phase loss: ≤200ms
Restart Delay Range 6 - 300s; automatic restart upon fault correction
Restart Delay Tolerance (%) ±15%
Trip Delay Range Adjustable from 0.25 - 30s
Trip Delay Tolerance (%) ≥15%
Overvoltage Trip Voltage (%) 109 - 113% of the adjusted line voltage
Overvoltage Reset Voltage (%) -2% of the trip voltage
Undervoltage Trip Voltage 88 - 92% of the adjusted line voltage
Undervoltage Reset Voltage (%) +2% of the trip voltage
Voltage Unbalance Trip Point (%) Adjustable from 2 - 10%
Phase Loss ≥15% unbalance
Indication 6 LEDs provide existing status and memory readout
Isolation Voltage (V) ≥2500V RMS input to output
Surge Protection IEEE C62.41-1991 Level B
Memory Type Nonvolatile RAM
Memory Capacity Stores last 10 faults
Life Mechanical - 1 x 107
Termination Type Screw terminals with captive wire clamps for up to #12 AWG (3.2mm2) wire
Mounting Method Suface mount with 2 or 4 #8 (M4 x 0.7) screws
Operating Temperature -40° to 65°C (-40°F to 149°F)
Storage Temperature (F/C) -40° to 85°C (-40°F to 185°F)
Dimensions 6.90 x 4.40 x 2.40 in. (175.3 x 111.8 x 61.0mm)
Weight (lbs/g) ≅25oz (709g)