GE MVAJ 11 to 34 Tripping and Control Relays

The MVAJ 11 to 34 range complements the more cost-effective range of MVAJ 051 to

MVAJ 205 tripping relays catering for the preferences of historical users.

MVAJ general characteristics can be found in table 1 that includes information on how

relay burden is modified at, or just after operation. ‘Economy’ indicates that the burden

reduced to a low value.

Instantaneous cut-off is a feature of some hand and electrical-reset elements and

the burden to zero, whilst others incorporate a time delay to enable series elements

operate. This time delay is 40 ms to 60 ms in all cases, except that of  type MVAJ 26

the delay is 2 s. All low burden relays are suitable for AC or DC operation. All high

relays are for DC operation only.

High Burden Tripping Types MVAJ 21. 23. 25. 26. and 29

These relays are suitable for use in high security circuit breaker tripping circuits.

particular they can be used in distributed tripping or control relay contact logic

where the initiating contact may be remote from the relay. The relays have a high

which is either cut-off at operation or economized to a low figure, either

or after a time delay.

The high burden provides immunity to capacitance discharge currents, which can result

the inception of an earth fault on battery wiring and immunity to the subsequent

current.

The high burden also permits the use of supervision relays such as type MVAX where

wiring is at risk and provides reliable operation of series elements such as repeat

type MCAA. For the latter purpose, type MVAJ relays can be provided with a time

economizing feature.

Description

Low Burden Tripping Relay Types MVAJ 11. 13. 14

These relays are suitable for applications where immunity to

capacitance discharge and high minimum operation currents are

not required.

Control Relay Type MVAJ 34

This is a dual-rated electrical-reset relay, the main function of

which is to switch protection and autoreclosing equipment in and

out of service from a remote point via pilot wires. It complies with

NGC SPEC. NGTS2.19:1996.

High Burden Tripping Relay Types MVAJ 21. 23. 25. 26. 27

Versions have one or two contact stacks depending on the number

of output contacts required.

Type MVAJ 21 High Burden Self-resetting Relay

This uses a contact on the main contact stack to energize a

separate, rear-mounted economizing element. After operation,

this reduces the burden by switching in resistance in series with

the main element and switching out shunt resistance.

Figure 2 shows a typical circuit diagram for self-resetting relays of

this type with high speed economy. When the main attracted

armature unit RL1 is energized by the protection contact PR, a

contact RL1-a energizes auxiliary element RL2. When contacts

RL2-a and RL2-b open, resistor R4 is put in series with RL1 while

the circuit to resistor R2 is broken.

Types MVAJ 23. 25 High Burden Tripping Relays

with Instantaneous Cut-off

These relays incorporate a break contact in series with the

operate coil. Located on the main contact stack, it is arranged to

break the coil circuit once the relay mechanism has completely

operated. This reduces the relay burden to zero as soon as

mechanical latching of the contacts has occurred.