Supply Monitoring Relays

A Few Words about 'Supply Monitoring Relays'

In today's modern society we rely more than ever on an electrical power supply to carry out our daily business with computers, air-conditioning, automated machines and even essentials like water supply and medical. The Midland Jay range of Supply Monitoring Relays or Phase Failure Relays have been tried and tested over the 40 years that we have been designing and manufacturing them and are there to monitor the supply and avoid unacceptable production problems caused by the loss of power supply. Some of the most recognisable problems are Loss of Phase, a Blown Fuse or Overloads and other less recognisable problems include over and under voltage, over and or under current, over and or under frequency and Phase Asymmetries. We offer a huge choice of Supply Monitoring Relays to cover your needs when using either a single phase supply, a 3 phase 3 wire or a 3 phase 4 wire supply with choices on the percentage monitoring on Imbalance, under-voltage, time delay and contact choice. Looking closer at the detail on the web will help you decide the one for you, however, should you need specific parameters simply talk to a member of our Technical Team.

Supply Monitoring Relays

Product Feature

Options

Single Phase

3 Phase

3 Wire

4 Wire

Under-Voltage

Fixed

Adjustable

Over-Voltage

Fixed

Adjustable

Imbalance

Fixed

Adjustable

Phase Rotation

Sensitive

Insensitive

Trip Delay Timer

Standard

True

Power On Delay Timer

Number of Output Contacts

1,2

2,4

1,2

Frequency Sensitive

Supply Quality Category open

Din Rail Enclosure

Euro Style

Box Style

Fully Enclosed

Relay Only

With Isol / Fuses

Trip Delay Timer
Where fitted the ‘Trip Delay Timer’ will inhibit the output contacts from releasing immediately a fault is detected.
The trip delay time is adjustable up to either 10 or 30 seconds depending on the model and will be either a ‘Standard’ delay or a ‘True’ delay type.
The 'Standard' delay type will require around 50% nominal supply voltage to be maintained for its operation, in the case of a total loss of power the unit
will trip with a minimal delay of approximately 0.5 seconds. This type of timer will allow the unit to ride through a short term voltage dip but not a total
power loss.
The 'True' delay timer is not dependent on the supply voltage for its operation. The timing function will be available in the case of either a partial or total
supply failure. This type of timer will allow the unit to ride through either a short term voltage dip or a total loss of power lasting up to 30 seconds.

Power On Delay Timer
Where fitted, the ‘Power On Delay Timer’ will delay the output contacts from energising immediately the supply voltage is applied to the unit for a period
of up to 30 seconds.
The supply voltage will have to satisfy the conditions set by the supply monitoring relay for a healthy supply continuously for the ‘Power On Delay’ timing
period before the output contacts will energise.
If the unit detects a fault and releases the output contacts the supply voltage will once again have to satisfy the requirements of a healthy supply continuously
for the ‘Power On Delay’ timing period before the output contacts will re-energise.