Installation and Operating Instructions - Crompton Instruments

Testing the function of Relay 3
With no measuring signal input, relay 3
should not be tripped.
Connect a 20 Amp AC constant current
source through any phase. Switch on the
current, and start a timer. After 2.4
seconds, the relay will trip, and the
51# symbol will appear in the relay
status display.
If the current source is not constant, the
trip time will be continuously recalculated
by SPR, and will vary in
proportion to that current.
If precision timing equipment is not
available, try injecting a smaller
overload, for example 8 Amps (which is
2x the setpoint) When the time dial
setting is set to approximately 10
seconds, the trip time will be ten
seconds. (calculation gives ideal time dial
setting of 9.8 for a 10 second trip time)
50