Millivolt Trip Protection Relays

Millivolt Trip Protection Relays


DIN rail mounting protection relays for use in single and three phase systems. Available in 55mm x 112mm or 100 x 112mm DIN rail cases

Download PDF

Selection Guide

M200-MVUmV under trip
M200-MVOmV over trip
M200-MVCmV combined under & over trip

Typical Applications

The mV trip relays will accept DC millivolt signals from shunts, sensors and transducers. A common application is to protect equipment from over current in a DC charging system.

For example using a 400 Amp / 75mV. The 75mV signal is fed to the M200-MVO, if the customer wishes to ensure that the current does not exceed 300 amps, then the MVO trip would be set at 75% (56.25mV). If the current went above 300Amps the relay would energise. As is common with all M200 relays, on over units the relay energises when the input signal exceeds the trip point. On under units the relay de-energises when the input signal goes below the trip point. A red LED indicates the state of the relay, whilst a green LED indicates the condition of the power supply.

Technical Specifications

Rated value mV DC10-999.9mV DC
Input Impedance50kOhm
Source Impedance100 ohms max
Overload10 x Input continuous
Range OverAdjustable 40 to 120%
Range underAdjustable 0 to 80%
RepeatabilityBetter than 0.5% of full span
Time DelayAdjustable 200mS to 10 seconds
DifferentialFixed 5%
AC Voltage115/230/400V ±25% / 45-65Hz/<2VA
DC Voltage24 volt (±20% / galvanically isolated)<3 watt
Single UnitsApprox 0.4kg.
Combined UnitsApprox 0.6kg. 100mm case

Ordering Information

Product CodeInput AuxFreqOptions
M200-MVU75mV230V50HzCal 40ºC


1Adjustable time delay: max 30 seconds
2AC auxiliary in range 57.7 to 480 volt
3Calibration at temperature other than 23ºC

Connection Diagrams

Call us now on: +44 1922 640003