Sequence Of Operation, Standard Transition; Preferred Source Loss And Return; Exerciser Operation - Kohler MPAC 1500 Manual

3.6 Sequence of Operation,
Standard Transition
The Sequence of Operation descriptions in Sections 3.6
through 3.9 describe the transfer switch normal
operation for standard, programmed, and closed
transition models, and for service entrance models.
Operation can be affected by faults such as the normal
or emergency contacts failing to open or close when
signaled to do so.
3.6.1 Preferred Source Loss and
Return, Standard Transition
Following is an explanation of the transfer switch
sequence of operation when Preferred Source failure is
detected.
Preferred Source Fails
1. Load control contacts open.
2. Engine start time delay expires.
3. The generator is signaled to start.
4. The generator starts and the standby source
becomes available.
5. Preferred-to-standby time delay expires.
6. Contactor transfers to standby.
7. Post-transfer load control sequences run.
8. Load control contacts close.
Preferred Source Returns
1. Standby-to-preferred and pre-transfer load control
time delays expire.
2. Load control contacts open.
3. Contactor transfers to preferred source.
4. Post-transfer load control sequences and engine
cooldown time delay expire.
5. Load control contacts close.
6. The engine start contacts open, signaling the
generator to stop.
26 Section 3 Operation
3.6.2 Exerciser Operation, Standard
Transition
Unloaded Exercise Sequence Starts
1. Exerciser timer begins.
2. The generator is signaled to start.
3. The generator starts and the standby source
becomes available.
4. The load bank control is activated.
Unloaded Exercise Sequence Ends
1. The load bank control is deactivated.
2. Engine cooldown time delay expires.
3. The engine start contacts open, signaling the
generator to stop.
Loaded Exercise Sequence Starts
1. Exerciser timer begins.
2. The generator is signaled to start.
3. The generator starts and the standby source
becomes available.
4. Preferred-to-standby time delay and pre-transfer
load control sequences run.
5. Load control contacts open.
6. Contactor transfers to standby.
7. Post-transfer load control sequences run.
8. Load control contacts close.
Emergency Source Fails (Normal Source is
available)
1. Exerciser is deactivated.
2. Load control contacts open.
3. Contactor immediately transfers to preferred.
4. Immediate failure to acquire standby alarm.
5. Post-transfer load control sequences and engine
cooldown time delay expire.
6. Load control contacts close.
7. Engine start contacts open.
TP-6714 4/10