Millivolt Trip Protection Relays

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


For over protection, under protection and combined under & over protection available in AC current AC voltage & frequency versions. Millivolt trip, DC voltage trip, Reverse Power, Phase sequence & Phase balance relays also available in our extensive range of protection relays..

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Selection Guide

M200-MVU mV under trip
M200-MVO mV over trip
M200-MVC mV combined 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 DC 10-999.9mV DC
Input Impedance 50kOhm
Source Impedance 100 ohms max
Overload 10 x Input continuous
Range Over Adjustable 40 to 120%
Range under Adjustable 0 to 80%
Repeatability Better than 0.5% of full span
Time Delay Adjustable 200mS to 10 seconds
Differential Fixed 5%
AC Voltage 115/230/400V ±25% / 45-65Hz/<2VA
DC Voltage 24 volt (±20% / galvanically isolated)<3 watt
Single Units Approx 0.4kg.
Combined Units Approx 0.6kg. 100mm case

Ordering Information

Product Code Input Aux Freq Options
M200-MVU 75mV 230V 50Hz Cal 40ºC


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

Connection Diagrams

Trip Protection Relays connection diagrams