Overcurrent-Lockout Testing - S&C MIcro-AT Installation, Programming, And Operation Manual

Overcurrent-Lockout
Testing
MANUAL/AUTOMATIC operation selector switch in Manual mode and
recouple each switch operator to its interrupter switch. Then, place the
MANUAL/AUTOMATIC operation selector switch in Automatic mode. To
ensure the source-transfer control is ready for automatic operation,
perform the final checks outlined under the "Before Walking Away"
section on page 32.
To simulate an overcurrent condition on the sources, perform the following:
STEP 9.
(a) With the manual/automatic operation selector switch in Automatic mode,
simulate a fault cleared by feeder fuses by momentarily pressing, and then
releasing, the OVERCURRENT key for the preferred source. This action will
"set up" the lockout feature, as indi cated by illumination of the LOCKOUT
lamp. Because the continuity of source voltage has not been affected, the
lockout-reset time delay will start; after it completes its preset cycle, the
lockout feature will automatically reset and the LOCKOUT lamp will
extinguish.
(b) To simulate lockout resulting from a fault cleared by a source-side
protective device, momentarily press, then release the OVERCURRENT
key for the pre ferred source—and, at the same time, press and hold in the
associated LOSS OF VOLTAGE key. The associated source voltage lamp
will extinguish. Fur ther, this action will "set up" the lockout feature, as
indicated by illumination of the LOCKOUT lamp.
With the switch operators in the normal configuration, if the LOSS OF
VOLTAGE key is held in long enough for the loss-of-source time delay to
complete its preset cycle, the preferred-source switch operator will move
to its Switch Open posi tion; the alternate-source switch operator will
remain in the Switch Open position, locked out.
(c) To cancel the lockout condition, perform the follow ing:
(1) Place the manual/automatic operation selector switch in Manual
mode.
(2) Press the "RESET" key. The LOCKOUT lamp will extinguish.
(3) Press the Close pushbutton on the preferred-source switch
operator. The switch operator will move to its Switch Closed
position.
(d) Place the manual/automatic operation selector switch in Manual mode and
recouple each switch oper ator to its interrupter switch. Then place the
man ual/automatic operation selector switch in Automatic mode. To be
sure that the source-transfer control is ready for automatic operation,
perform the final checks outlined under the "Before Walking Away"
section on page 32.
Operational Testing
S&C Instruction Sheet 515-600 31