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IB140042EN
Instructional Booklet
Page
28
Effective: May 2015
ATC-300 /900 Breaker Based Transfer Switch
Section 5: Operation
5.1 General
An ATS provides main contacts to connect and disconnect the
load to and from the Source 1 and Source 2 power sources (Sec-
tion 3.2.2). Each transfer mechanism provides the mechanical
motion required to open and close the mechanically interlocked
main contacts (Section 3.2.3).
Note that the transfer mechanisms for the two types of ATSs
described in this booklet (30-150 A and 225-1200 A) are different
for both the manual and automatic modes.
I
Figure 30.
Motor Disconnect P3 must be disconnected.
5.2 Manual Operation (225-1200 A)
The manual operating handle can be used to create the rotational
motion required to open and close the main contacts through a
rigid mechanical interlocking system (Figure 32). An indicator
wheel attached to the operating handle and mechanical interlock-
ing system rotates with each movement of the handle to open
and/or close the main contacts (Figures 33). Three distinct switch
positions are provided and indicated visually on the indicator
wheel (Figure 34).
Figure 31. ATS Manual Operating Handle in Use (225-1200 A
Models).
Figure 32. Indicator Wheel Mounted in the Switch with Motor
Under the Wheel (225-1200 A Models).
NOTICE
IF AN ATS WITH ANY TYPE OF ELECTRICAL OPERATING CAPABILI-
TIES IS TO BE OPERATED UTILIZING THE MANUAL OPERATING
HANDLE, IT IS STRONGLY RECOMMENDED THAT THE TRANSFER
MOTOR CIRCUIT FIRST BE ISOLATED. THIS IS ACCOMPLISHED BY
UNPLUGGING THE (P3) PLUG MARKED MOTOR DISCONNECT (FIG-
URE 31). ANY ATTEMPT TO USE THE MANUAL OPERATING HAN-
DLE WITHOUT FIRST ISOLATING THE MOTOR CIRCUIT CAUSES AN
AUTOMATIC TRANSFER.
P3
