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9. Maintenance of the PT Trip Unit
The trip unit itself requires no maintenance.
9.1 Replacing the Battery
The battery is provided to maintain the LED indication
of the cause of trip. A battery icon at the bottom of the
display indicates remaining battery life. The battery plays
no part in the protection function of the trip system. The
battery can be replaced at any time, even while the circuit
breaker is in-service, without affecting the operation of
the circuit breaker or its protection functions.
On the initial installation of the circuit breaker, pull to
remove the battery tray, remove and discard the insulating
tab, and then re-insert the battery tray.
The 3 V lithium battery (CR 2032) is easily removed and
replaced; pull to remove the battery tray, remove the old
battery from the holder, replace with a new one (observe
proper polarity as marked on the tray), and then re-insert
the battery tray into the slot on the frame module. The
replacement battery should be the same type as that
already in the trip unit or an equivalent. Accidentally
installing the battery in the reverse direction will not harm
the battery nor the trip unit, but will defeat the function of
the battery.
Figure 15. Replacing the Battery.
Exercise care when replacing the battery to ensure that
it is installed correctly. Accidentally installing the battery
in the reverse direction will not harm the trip unit nor the
battery, but will defeat the function of the battery.
PT 10 TrIP UnIT User ManUal Power TrIP (PT) UnITs MN013021EN January 2024 www.eaton.com
CAUTION
9. Maintenance of the PT Trip Unit
9.2 Replacing the Trip Unit
The PT trip unit is designed as a field replaceable unit.
Remove the circuit breaker front cover. Use a screwdriver
to loosen the top and bottom screws. Note that the
bottom screw is located between the 2-pin auxiliary
power socket and USB port, and is covered by a door.
Pull the unit outward to disengage the molded, 40-pin
connector from the frame module printed circuit board.
Remove the wiring connector and harness from the top of
the trip unit.
For further information see IL0131234ZU.
Figure 16. Location of the Top and Bottom Trip Unit
Screws.
To install the new trip unit, first connect the wiring
harness at the top of the trip unit. Then, to mount the
trip unit, align it with the two guide grooves of the frame
module. Keep it parallel with the receiving, molded
housing. Press the unit into the circuit breaker until the
trip unit seats firmly into the receiving housing. Secure it
in place with the two screws supplied using a screwdriver
with a maximum screw torque of 1.0 N·M (8.9 lbf/in.).
Replace the circuit breaker front cover.
Screws
Guide Grooves
13
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