Kohler ZCS series User Manual

TP-5660 11/9810 Operation
The transfer switch logic controller circuitry,
programming, or accessories determine when a power
source is acceptable, has failed, or has been restored
and operates accordingly. Failure of a power source
occurswhen thethe voltageand/or frequency onone or
more phases fall below preset limits. A power source is
acceptable when the voltage and/or frequency on all
monitored phases rise above preset levels. A power
source is restored when it becomes acceptable after
failing. Typical ATS operation is divided into two
sequences.
D Failure of the normal power source and the
resulting transfer to the emergency source or
Emergency.
D Restorationofthenormal powersourceandthe
resulting transfer back to the normal source or
Normal.
The following sections briefly explain these sequences
of operation. Installed controller accessories can
change the sequence of operation. See the logic
controller operation and installation manual for
specifications on time delays, voltage and frequency
limits, control adjustments, and accessory information.
2.2.1 Failure of Normal Power
When the normal power source fails, the controller
starts a time delay called Time Delay Engine Start
(TDES). TDES prevents unnecessary generator
startup during short normal power interruptions. If the
normalpower sourceisrestored beforeTDES ends,the
controller resets the time delay. If the normal power
failure persists and TDES ends, the controller issues a
signal to start the standby (emergency) generator to
produce the emergency power source.
After signalling the generator to start, the controller
monitors the emergency power source. When the
controller determines that the emergency (generator)
power source is acceptable it starts a time delay called
Time Delay Normal to Emergency (TDNE). TDNE
allows emergency power source stabilization before
loadconnection andprevents nuisancetransfersduring
short power interruptions. When TDNE ends the
controller signalsthe transfer switch toconnect theload
to the emergency source.
Afterloadtransfertheswitchmechanicallylatchesinthe
emergency position, supplying emergency source
power to the load until normal power source restoration
and stabilization.
2.2.2 Restoration of Normal Power
After normal power source restoration, the controller
starts a time delay called Time Delay Emergency to
Normal(TDEN). If thenormalpower sourcefailsbefore
TDEN ends, the time delay resets. TDEN ensures
normal power source stabilization before load
reconnection.
When the controller determines that the normal power
source has maintained an acceptable level and TDEN
ends, the controller signals the power switching device
to reconnect the load to the normal source.
Afterloadtransfertheswitchmechanicallylatchesinthe
normal position and the controller starts a time delay
called Time Delay Engine Cooldown (TDEC), if
equipped. TDECallowstheengineandgeneratortorun
unloadedandcooldownbeforeshutdown. WhenTDEC
expires the controller signals the generator set to shut
down.
The generator set controller may allow the generator to
run for an additional cooldown period after the transfer
switch signals a shutdown. Consult the generator set
operation manual for more information.

Kohler ZCS series Specifications

General

Brand	Kohler
Model	ZCS series
Category	Switch
Language	English