46
Operation and maintenance of
IZM low voltage air circuit breakers
MOELLER
www.moeller.net/de/support
10/09 AWB1230-1605
Effective October 2009
Figure 71. Use of Contact Wear Indicator with Circuit Breaker Closed
Side-to-Side
Ledge
Side-to-Side
Ledge
Contact Wear Indicator—
Contacts Closed and Wear is Indicated
Contact Wear Indicator—
Contacts Closed and in Good Condition
Contact Wear Inspection Area
(ledge now becoming visible under contacts)
Contact Wear Inspection Area
(ledge not visible under contacts)
Circuit breaker modifications and changes
The topics discussed here will relate to those actions that can
be taken in the field to change, update, maintain, or repair an
IZM circuit breaker. This information does not, however, include
most accessory devices. Their installation is covered by separate
instruction leaflets dedicated to the individual devices. The tasks
described here do not, under ordinary circumstances, require any
assistance beyond the appropriate instructional material. If further
assistance is required, however, contact your Moeller representative.
Rating plug replacement
nOTiCE
iF a raTing PLUg iS nOT inSTaLLED in THE TriP UniT, THE TriP UniT
WiLL TriP WHEn EnErgiZED. aLSO rEMEMBEr THaT THE TriP UniT’S
raTing PLUg anD THE CirCUiT BrEakEr’S CUrrEnT SEnSOrS MUST
HaVE MaTCHing raTingS.
To remove the rating plug from the trip unit, open the small rating
plug door located on the right side of the trip unit (
). The
trip unit’s battery cavity is also located behind this door. Use a
1/8-inch wide screwdriver to remove the M4 screw holding the
rating plug in position. Pull the door to release the rating plug from
the trip unit.
Figure 72. Trip Unit Rating Plug Location
To install a new rating plug, insert the rating plug into the cavity
where the other rating plug was removed. Make sure the three
pins on the rating plug are aligned with the sockets in the cavity.
The rating plug should fit with a slight insertion force.
