Specifications

6 Distribution Products Catalog CA08101001E—October 2010 www.eaton.com
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16.1
Tr a n s f er Switches
Tr a n s f er Switch Equipment
Product Description
For more information on
“Transfer Switch Panels,”
refer to
Section 4 of this
catalog “Advanced
Residential Products.”
Eaton’s Automatic Transfer
Switches are reliable, rugged,
versatile and compact
assemblies for transferring
essential loads and electrical
distribution systems from
one power source to another.
Transfer switches can
be supplied in separate
enclosures for stand-alone
applications or can be
supplied as an integral
component in the following
equipment (see table below).
Product Type
Application Description
A transfer switch is a
critical component of any
emergency or standby power
system. When the normal
(preferred) source of power
is lost, a transfer switch
quickly and safely shifts the
load circuit from the normal
source of power to the
emergency (alternate) source
of power. This permits critical
loads to continue running
with minimal or no outage.
After the normal source of
power has been restored,
the retransfer process returns
the load circuit to the normal
power source.
Transfer switches are
available with different
operational modes including:
●
Manual
●
Non-automatic
●
Automatic
●
Bypass isolation
●
Soft load
●
Maintenance bypass
The power switching
operation of transfer switches
may be separated into the
three key categories of:
●
Open transition—break-
before-make operation:
●
In-phase transfer
transition
●
Delayed transition
●
Closed transition—make-
before-break operation
●
Closed transition soft
load—both sources are
paralleled and can remain
so indefinitely
The three basic components
of a transfer switch are:
●
Power switching device to
shift the load circuits to
and from the power source
●
Transfer logic controller
to monitor the condition
of the power sources
and provide the control
signals to the power
switching device
●
Control power source to
supply operational power
to the controller and
switching device
Description
Section
Reference
Magnum™ DS Switchgear 19
DS II Switchgear 19
Pow-R-Line™ Switchboards 15
Motor Control Centers 18
Panelboards 14
UL 1008 Endurance Testing
The importance of specifying a
UL 1008 transfer switch can
be seen in the table below.
When specifying any UL 1008
transfer switch, you can be
assured the switch has met
and passed the following
endurance testing.
UL 1008 Life Expectancy
Transfer switch applications
typically require a plant
exerciser once a week or
once a month. The table
below demonstrates the life
expectancy operating the
UL 1008 switch once a week
for the life of the switch.
UL 1008 Endurance Testing
UL 1008 Life Expectancy
Typical Applications
All Eaton transfer switches
are designed to meet the
requirements set forth by
UL
®
1008; however, all
transfer switches are not
created equal. You can be
assured of safe and reliable
operation from all types
of transfer switches that
Eaton offers.
ATS Rating
(Amperes)
Rate of Operation
Per Minute
With
Current
Without
Current Total
0–300 1 6000 — 6000
301–400 1 4000 — 4000
401–800 1 2000 1000 3000
801–1600 0.5 1500 1500 3000
1601–4000 0.25 1000 2000 3000
ATS Rating
(Amperes)
Minimum
Operations
Per Year
Life Expectancy
in Years With
Current Applied
Life Expectancy
in Years Without
Current Applied
0–300 52 115 115
301–400 52 76 76
401–800 52 38 57
801–1600 52 28 57
1601–4000 52 19 57