Product Manual A

3 Description

3.1 Cabinet

Cabinets are available in various configurations that meet UL and National Electrical Manufacturer's

Association (NEMA) requirements. Each cabinet includes an identification label. The standard cabinet

offerings are:

• Type 1 Indoor - general purpose

• Type 3R Outdoor - rainproof

• Type 4 Outdoor - watertight

• Type 4X Outdoor - watertight, stainless steel

• Type 12 Indoor - dust tight

3.2 Transfer Switch Components

The transfer switch opens and closes the contacts that transfer the load between the power sources

(Source 1 and Source 2). The switch is mechanically interlocked to prevent simultaneous closing to both

power sources (except in switches capable of closed transitions).

3.2.1 Contact Assemblies

The automatic transfer switch has either three or four poles. Three pole transfer switches are provided

with a neutral bar. The contact assemblies make and break the current flow. When closed to either power

source the contacts are mechanically held. A mechanical interlock prevents them from closing to both

power sources at the same time.

3.2.2 Linear Actuator

The linear actuator moves the contact assemblies between the contacts of both power sources. Linear

actuator operation is initiated automatically by the transfer switch control. Manual operation of the switch is

also possible.

3.2.3 Auxiliary Contacts

Auxiliary contacts are provided on the utility and genset sides of the transfer switch. They are actuated by

operation of the transfer switch during transfer and retransfer. The utility auxiliary contact switch is

actuated when the transfer switch is connected to the utility. The genset auxiliary contact switch is

actuated when the transfer switch is connected to the genset. The auxiliary contacts have current ratings

of 10 amperes at 250 VAC. The contacts are wired to terminal block TB1.