Specifications

12 Distribution Products Catalog CA08101001E—October 2010 www.eaton.com
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16.2
Tr a n s f er Switches
Contactor-Based Designs
Contactor-Based ATS with ATC-800 Controller
Contents
Description Page
Automatic Open Transition, 40–1200A . . . . . . . . . . . . . . . . 8
Automatic Closed Transition, 40–1200A . . . . . . . . . . . . . . . 12
Features, Benefits and Functions . . . . . . . . . . . . . . . . . . 13
Catalog Number Selection . . . . . . . . . . . . . . . . . . . . . . . 14
Technical Data and Specifications . . . . . . . . . . . . . . . . . . 14
Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Bypass Isolation Transfer Switches, 40–1200A,
Dual Drawout. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Bypass Isolation Transfer Switches, 40–1200A,
Fixed Bypass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Automatic Closed Transition, 40–1200A
Product Description
Eaton’s closed transition
contactor-based automatic
transfer switch (CTC8) is
designed to avoid intentional
interruption of power when
both sources of power are
available by momentarily
paralleling both sources.
The ATC-800 is a
comprehensive, multi-
function, microprocessor-
based controller, offering
extensive monitoring, status
reporting and transfer control
operation.
The make-before-break
contact sequence coupled
with Eaton’s ATC-800
provides a transfer switch
that is useful in critical
standby power applications
available from 40–1200A.
Application Description
A transfer switch designed
for closed transition has
make-before-break contacts
that require the normal and
alternate sources to be
synchronized. The source
contacts on Eaton’s CTC8
will parallel for 100 ms or
less. The ATC-800 provides
all-phase undervoltage,
underfrequency, and
overvoltage and
overfrequency protection
as a standard. Consult with
the local utility company for
permission and to verify the
protection requirements as
each utility may have
different rules regarding
closed transition applications.
Protective relays may be
available as an option upon
request.
Closed transition controls
The CTC8 accomplishes the
closed transition transfer by
monitoring the voltage and
frequency set point
conditions of both power
sources. Once the set point
conditions are met, the ATC-
800 controller will start the
closed transition
synchronization timer (TSCT).
The TSCT is adjustable from
1–60 minutes in duration.
This duration is the time
during which the ATC-800
controller will monitor the
phase angles to anticipate
when they will be within 8
electrical degrees. The closed
transition scheme is
anticipatory, allowing the
close contacts signal to be
initiated before the sources
are exactly in phase. If the
TSCT times out and the
transfer switch has not
reached synchronization, the
transfer switch will remain
connected to the current
power source and a failure to
transfer alarm will be
displayed.
The transfer switch can also
be equipped with an optional
open transition transfer
method for situations where
synchronization is not
possible, but a transfer is
required. One of the
following transition features
can be selected:
●
Closed transition only
●
Closed transition with
default to load voltage
decay
●
Closed transition with
default to time delay
neutral