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PT UNIT USER MANUAL
APRIL 2023 www.eaton.com.cn
Figure 2. Series IZM6 Circuit Breakers
IZM61
IZM65/67
The current sensors are internal to the circuit breaker frame
and consist of two coils: one coil on an iron core and one
coil on an air core (Rogowski coil). As current begins to flow
through the circuit breaker, the iron core coil generates a
secondary current which powers the trip unit. At the same
time, the air core coil provides signals which are processed to
determine the current through the circuit breaker.
The mechanical action required to initiate tripping of the
circuit breaker is provided by a special low-energy trip
actuator. This trip actuator is an integral part of the circuit
breaker mechanism which also includes a charging handle,
and manual “Open” and “Close” buttons. The trip actuator is
automatically reset by the mechanism.
The wiring diagrams show how certain functions of the trip
unit are connected to external circuits. All wirings are landed
on the secondary contact system directly above the circuit
breaker. See ZIM6 Air Circuit Breaker catalogue for the
secondary terminal board definitions.
1. Introduction
