TS 910 TRANSFER SWITCH
PM140 REV 0 12/02/09
8
Thomson Technology
5.
GENERAL THEORY OF OPERATION
5.1.
AUTOMATIC SEQUENCE OF OPERATION
Note
: Time delays indicated below are factory default settings only. Refer to
Section 18.15
of this
manual for alternate time delay settings available on TSC 9 Controller
UTILITY POWER FAIL
When voltage drops on any phase of the utility supply below 70%
of rated voltage, a generator start sequence will be initiated.
GEN START
The generator will start following expiry of the 3 second
Gen
Start
timer.
GEN WARM-UP
A generator warm-up period will be initiated once the generator
starts and reaches 80% rated voltage and 90% rated frequency.
TRANSFER TO GEN
The load will transfer to the generator supply following expiry of
the 10 second
Gen Warm-up
timer.
LOAD SHED ACTIVATE
All non-essential loads connected to Load Shed control circuit
will be de-energized once generator transfers on load (If kW
Load Shed option is installed, refer to Section 18.16 of this
manual for further details).
UTILITY POWER RETURN
When utility power is restored to above 80% rated voltage on all
phases, a utility power return sequence will be initiated.
TRANSFER TO UTILITY
The load will transfer from generator to utility power following
expiry of the 120 second
Utility Return
timer, provided both
generator and utility voltages are in-phase at time of transfer.
LOAD SHED RESET
All non-essential loads connected to Load Shed control circuit
will be re-energized once load transfers to utility power.
GEN COOL DOWN
The generator will automatically stop following expiry of the 2
minute
Gen Cool Down
timer.
5.2.
SERVICE ENTRANCE AUTOMATIC TRANSFER SWITCH OPERATION
5.2.1. OVER CURRENT
TRIP
Should the utility breaker trip open due to an over current condition, TSC 9 transfer
controller will initiate an engine start signal and will permit transfer of the load to the
generator supply. The utility source will be locked out and the load will remain on the
generator supply until the Utility Service Entrance breaker is manually reset.
5.2.2. SERVICE DISCONNECT PROCEDURE
To initiate a Utility Supply Service Disconnect, follow procedure shown below:
5.2.2.1.
TURN OFF GEN STARTING CONTROL: At the generator set,
turn it’s automatic starting control to OFF position to prevent generator
