S&C Instruction Sheet 515-600 13
Operating Description
If the overcurrent is due to a fault that is cleared by a source-side protective device,
the prolonged loss of source voltage will cause the associated source inter rupter switch
to open, and the
Overcurrent Lockout
feature will pre vent the other source interrupter
switch from closing into the fault.
After the fault has been located and repaired, the manual/automatic operation selec-
tor switch must be set in
Manual
mode and the RESET key pressed to cancel the lockout
condition, which will extinguish the LOCK OUT lamp.
Service to the load can then be restored by pressing the CLOSE pushbutton on the
preferred-source inter rupter switch operator. If, however, voltage is not avail able on the
preferred source, service to the load can be restored by pressing the CLOSE pushbutton
on the alternate-source interrupter switch operator. After the source interrupter switch
has closed, the manual/auto matic operation selector switch should be placed in the
Automatic
setting. If the normal condition has been restored, the automatic-transfer
READY indicating lamp will light.
If the overcurrent is due to a fault that is cleared by a load-side protective device, no
switching will occur because loss-of-source voltage is not of sufficient duration to ini-
tiate opening of the source interrupter switch serving the load. In this case, although the
fault current initially “sets up” the
Lockout
feature (and the LOCKOUT lamp lights), the
subsequent return of normal source voltage will actu ate the lockout-reset time delay
●
.
After this predetermined time delay, the
Lockout
feature will automatically reset and
the control will return to its normal state and the LOCKOUT lamp will extinguish.
●
Factory-set at 20 .0 seconds .
