55
User Manual MN013016EN
Effective July 2022
Magnum PXR and Power Defense SB low
voltage power circuit breakers user manual
EATON www.eaton.com
Table 25. Contact opening
Problem Possible root cause Actions
Breaker will not open on expected
trip unit settings
Pinched or damaged wires Repair damage
Damaged trip actuator (TA) Contact Eaton Electrical Services & Systems
Broken TA tripper Contact Eaton Electrical Services & Systems
Trip unit settings not as desired Reset trip unit to proper settings
Trip unit not communicating correctly Check communication devices and wiring
Breaker will not open by way of
accessories
Voltage at shunt trip too low Excessive voltage drop in control wiring
Mis-wired open accessories Correct secondary wire connections
Accessory not fully seated Fully seat and lock accessory
Shunt trip cutoff switch not connected, present,
or damaged (instantaneous shunt trip only)
Connect, install, or replace shunt trip cutoff switch
Accessory deck broken or not locked down Replace or lock down accessory deck
Other unidentified causes Contact Eaton Electrical Services & Systems
Breaker will not open mechanically Obstruction behind off pushbutton Remove obstruction
Pushbutton cover blocking access to OPEN pushbutton Remove cover.
Other unidentified causes Contact Eaton Electrical Services & Systems
Table 26. Levering-in/-out (drawout applications only)
Problem Possible root cause Actions
Breaker will not rack in Breaker does not push to stops evenly Ensure breaker is square against stops by pushing evenly on both
sides of the breaker
Breaker/Cassette are equipped with mismatching rejection bracket
assemblies.
Ensure that rated current on the breaker matches the rated current
of the cassette. Check that cassette rejection bracket pin scheme
matches the cassette catalog number.
Attempting to rack in a breaker with PXR into a Digitrip cassette. Replace cassette
Cassette floor pan mounting bolts in wrong location or
not low profile
Remove bolt and replace with low profile
Arc hood displaced and interfering with breaker movement Replace arc hood
Cassette secondary sliding bracket not free to move with breaker Remove wire obstruction or lubricate slide bushings and pin
Lev in device require re-lubrication Lubricate lev in device
Excessive drive screw torque causing stripping or bending of
key components
Contact Eaton Electrical Services & Systems
Racking screw not in full retracted position before pushing breaker
into cell
Rotate to full counterclockwise stop
Breaker will not rack out Other unidentified causes Contact Eaton Electrical Services & Systems
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