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IB140015EN
Instructional Booklet
Page
6
Effective: August 2014
ATC-900 Magnum Tranfer Switch O & M Manual
1.3 Magnum Fixed and Drawout Switching Devices
1.3.1 General Magnum Switching Device
In a typical Magnum automatic transfer switch, the switching
device is a Magnum power case switch. The magnum power case
switch does not include an overcurrent trip. For specific applica-
tions like an integrated service entrance rated automatic transfer
switch or an application where it is desirable to include overcur-
rent trips to the magnum device, a magnum breaker can be pro-
vided on either or both Source 1 and/or Source 2 device. In
those cases the magnum device includes an overcurrent trip. The
standard trip unit is a Digitrip 520. Optionally a digitrip 520M,
520MC, or 1150 can be provided.
Figure 5. The Magnum Fixed Switching Device.
The magnum power case switch can be provided in a standard
fixed mounted design or an optional drawout design. Bypass iso-
lation automatic transfer switches are provided with all drawout
type designs. In addition the 4000A and 5000A designs come
standard with drawout magnum power devices.
Figure 6. The Magnum Drawout Switching Device.
The Magnum transfer switches are available in the following con-
figurations:
Table 2. Magnum Transfer Switch Configurations
All Magnum switching devices are 100% rated, Underwriters Lab-
oratories (UL) listed, and are built and tested in an ISO 9002 certi-
fied facility to applicable NEMA, ANSI, IEEE, and UL standards.
For more information on Magnum switching devices, consult the
Magnum switching device manual supplied with the transfer
switch.
The main difference between the fixed and drawout versions of
the Magnum switching devices used in the Magnum transfer
switch is the mounting method. Fixed switching devices are
bolted directly into the transfer switch frame while drawout
switching devices are mounted in an extendable carriage within
the transfer switch, allowing the switching device to be “drawn
out” for service, maintenance, and/or replacement.
NUMBER OF
SWITCHING DEVICES
SWITCHING DEVICE
TYPE
2
Fixed
2
Drawouts
4 (Bypass Isolation)
Drawouts
