Section 3: Equipment Description; General; Power Panel; Main Contacts - Eaton Cutler-Hammer O & M Manual

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SECTION 3: EQUIPMENT DESCRIPTION

3.1 GENERAL

This Cutler-Hammer transfer switch equipment is avail-
able in three configurations:
• Basic Transfer Switch (open transition only)
• Automatic Transfer Switch
• Non-Automatic Transfer Switch (electrically operated,
open transition only)
Refer to Section 1 for a discussion of all types. Each
transfer switch is usually supplied in an enclosure,
although unmounted sub-assemblies can be supplied for
mounting by the customer. Since the enclosed automatic
transfer switch encompasses all transfer switch equip-
ment possibilities, it is the only specific type that will be
discussed in this section.
Figure 3-1 Typical Mini Power Panel
(closed transition shown)
The enclosed automatic transfer switch consists of three
basic panels interconnected through connector plugs
and mounted in an enclosure:

• Power Panel

• Voltage Selection Panel
• Logic Panel
- ATC-600 (open transition only)
- ATC-800 (closed transition only)
The components comprising the three panels are installed
in accordance with the specific requirements of the circuit
being controlled. Each transfer switch is, therefore, tailor-
made to a specific application.
3.2 POWER PANEL
The power panel consists of a means for making load,
power, and neutral connections. The main contacts and
the transfer mechanism are all on one steel frame
(Figure 3-1).

3.2.1 MAIN CONTACTS

The main contacts connect and disconnect the load to
and from the different power sources. High withstand
insulated case switches (Figure 3-2) are the main con-
tacts for the Normal and Emergency power sources in
standard, unmodified automatic transfer switches.
Optional integral thermal and short circuit protection in
either or both switching devices is available (Figure 3-3
and Section 3.6). These continuous duty devices are
rated for all classes of loads. In addition, they have high
dielectric strength, heavy-duty switching and withstand
capabilities, and high interrupting capacity.

3.2.2 INTERLOCKS (OPEN TRANSITION ONLY)

Cutler-Hammer transfer switches are mechanically and
Figure 3-2 Insulated Case Switch
(closed transition shown)
IB01602002E
Effective 10/02