TSC 800 TRANSFER SWITCH CONTROLLER
PM 049 REV 9 06/04/24 Thomson Technology
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opening), the transfer to utility supply signal (contact closure) will be given to the
transfer switch mechanism. The load will then be transferred from the generator
supply back to the utility supply. During the utility re-transfer sequence a neutral
position delay circuit can be employed which will cause the transfer mechanism to
pause in the “neutral position (i.e. with both transfer power switching devices open) for
the duration of the neutral delay timer (0 -120 seconds adjustable) setting, once the
time delay expires, the re-transfer sequence will be completed. The Neutral Delay
Bypass feature can also be enabled to detect when all load phases voltages have
dropped below 20% of the nominal system voltage, which will cancel any remaining
Neutral Delay time and complete the transfer.
An engine cooldown timer circuit will be initiated once the load is transferred from the
generator supply and determined to have made position by ensuring the load bus is
energized and the Utility position indication confirmed. Following expiry of the
cooldown delay period (0 – 50.0 min. adjustable) the engine start signal will be
removed (remote start contact opened) to initiate stopping of the generator set.
6.1.2. NORMAL SEQUENCE OF OPERATION (CLOSED TRANSITION
TRANSFER)
For transfer switches equipped with the closed transition transfer option, the TSC 800
is configured to provide additional logic for this application. When the TSC 800
controller receives an input signal for Closed Transition Transfer Mode (contact closing
on TB2-12) the TSC 800 is configured to operate as follows:
Under normal closed transition operating conditions, the transfer switch operates
automatically during a failure and restoration of utility power and does not require
operator intervention.
When utility supply voltage drops below a preset nominal value (70 - 99% of nominal,
adjustable) on any phase, an engine start delay circuit will be initiated. Following
expiry of the engine start delay period (0 - 60 sec. adjustable) an engine start signal
(contact closure) will be given.
Once the engine starts, the transfer switch controller will monitor the generator voltage
and frequency levels. When the generator voltage and frequency rises above preset
values (70 - 99% of nominal, adjustable) a warm up time delay will be initiated. When
the warm up timer (0 – 3000 Sec. adjustable) expires the transfer to utility supply
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