Introduction; Safety Precautions; General Description; Type A - Eaton Cutler-Hammer MP1 Series Instructions Manual

I.L.15.01.T.K.

3. Introduction

This technical document is intended to cover
most aspects associated with the
installation, application, operation and
maintenance of the ATS-MP1 and ATS-
MP1-E series controller. It is provided as a
guide for authorized and qualified personnel
only in the selection and application of an
Automatic Transfer Switch with the Cutler-
Hammer ATS-MP1 series controller. Please
refer to the specific WARNING and
CAUTION in Section 3.1 before proceeding.
If the purchaser requires further information
regarding a particular installation, application
or maintenance activity, a Cutler-Hammer
representative should be contacted.

3.1 Safety Precautions

All safety codes, safety standards and/or
regulations must be strictly observed in the
installation, operation and maintenance of
this device.
WARNING
THE WARNINGS AND CAUTIONS
INCLUDED AS PART OF THE
PROCEDURAL STEPS IN THIS
DOCUMENT ARE FOR PERSONNEL
SAFETY AND PROTECTION OF
EQUIPMENT FROM DAMAGE. AN
EXAMPLE OF A TYPICAL WARNING
LABEL HEADING IS SHOWN IN
REVERSE TYPE TO FAMILIARIZE
PERSONNEL WITH THE STYLE OF
PRESENTATION. THIS WILL HELP TO
INSURE THAT PERSONNEL ARE ALERT
TO WARNINGS, WHICH MAY APPEAR
THROUGHOUT THE DOCUMENT.
CAUTION
COMPLETELY READ AND UNDERSTAND
THE MATERIAL PRESENTED IN THIS
DOCUMENT BEFORE ATTEMPTING
INSTALLATION, OPERATION OR
APPLICATION OF THE EQUIPMENT. IN
ADDITION, ONLY QUALIFIED PERSONS
SHOULD BE PERMITTED TO PERFORM
ANY WORK ASSOCIATED WITH THE
EQUIPMENT. ANY WIRING
INSTRUCTIONS PRESENTED IN THIS
DOCUMENT MUST BE FOLLOWED
PRECISELY. FAILURE TO DO SO COULD
CAUSE PERMANENT EQUIPMENT
DAMAGE.
Effective June 2000

3.2 General Description

CSA Standard C22.2 No. 178-1978 defines
an automatic transfer switch as, "self acting
equipment for transferring one or more load
conductor connections from one power
source to another." The same Standard also
gives definitions for type A and type B
automatic transfer switches. "Transfer switch
type A means an automatic transfer switch
that does not employ integral overcurrent
devices." "Transfer switch, type B means an
automatic transfer switch that (does) employ
integral overcurrent protection." Cutler-
Hammer automatic transfer switches are
available in both types.
3.2.1

Type A

Type A are equipped with special
instantaneous magnetic only interrupters.
The trip settings of these special interrupters
are set (and fixed) at higher than standard
values. They are intended to trip only if the
upstream protective device fails to clear a
fault. Incorporating these special magnetic
only interrupters, a type A automatic transfer
switch operates in exactly the same way as
a transfer switch not having this feature. In
the event that both devices trip, the control
circuitry will automatically initiate transfer to
the alternate source. The transfer operation
will reset the "tripped" magnetic only
interrupter.
3.2.2

Type B

Type B switches are equipped with standard
moulded case circuit breakers with standard
thermal-magnetic trip units that will provide
the required over-load and short circuit
protection. Type B switches can also be built
using electronic trip units, which gives the
ability to include ground fault tripping, as
well as overload (long and short time) and
short circuit protection (instantaneous). For
application information or assistance with
type B switches, refer to Cutler-Hammer.
For the remainder of this manual, the
switching devices employed in the switch
shall be referred to as breakers. This can
imply either magnetic-trip only moulded case
switches (MCS), or moulded case circuit
breakers (MCCB) with overcurrent trip units.
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