Eaton ATC-900 Automatic Transfer Switch Controller Features

Emergency source

The emergency source is defined as the source that is not preferred.

If NONE is chosen for the preferred source setting, the emergency

source will be the source that is presently not attached to the load.

Therefore, in this condition after a transfer, the normal and emer

gency sources will switch between source 1 and 2.

Features

The ATC-900 has many features that are available to the user. These

features are standard and are available depending on the type of

transfer switch used (i.e. contactor, power frame switch/breaker,

or molded case switch/breaker). Appendix A has a list of all of the

features including any acronyms used along with a brief description.

See Table 8 “ATC-900 features” for a compact list of features, includ

ing a full list of available I/O. Consult Section 5 and Appendix B for

I/O descriptions. For some transfer switch configurations, standard

control input(s) and/or standard relay output(s) will come prepro

grammed from the factory. An example of this is service entrance

which requires the go to neutral input.

The ATC-900 is configured as either open-transition or closed-transi

tion. Closed-transition operation is covered in section 1.5.3.

Some ATC-900 programmable features are only available on specific

transfer switch construction types. By example, a contactor type

transfer switch (2-position) does not allow the electrical load to be

disconnected for a programmed time delay period therefore the

TDN (time delay neutral) feature is not available. A molded case type

transfer switch is mechanically interlocked to prevent paralleling of

the power sources therefore the closed transition feature is not available.