WEG Molded Case Circuit Breakers - User’s Manual
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WEG Molded Case Circuit Breakers - User’s Manual
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3.3. PUSH-TO-TRIP BUTTON
The PUSH-TO-TRIP button operates the circuit breaker tripping function and may
be periodically used to exercise the operating mechanism. In thermal magnetic trip
units, the button is designed to be operated by a small screw-driver.
3.4. THERMAL-MAGNETIC TRIP UNIT ADJUSTMENT
The magnetic element of each pole of the trip unit is adjusted by rotating the
adjustment buttons on the front of the trip unit with a screwdriver. The buttons
have several settings as indicated on the nameplate with values in multiples of the
trip unit ampere rating (I
n
).
To adjust the setting, rotate each button clockwise until arrow on button points to
desired setting. The molded case switch is set at the factory (at 8X) and is not field
adjustable.
4. INSPECTION AND FIELD TESTING
UBW800 molded case circuit breakers are designed to provide years of almost
maintenance-free operation. The following procedure describes how to do a
limited amount of field inspection and testing of a circuit breaker.
4.1. INSPECTION
Circuit breakers in service should be inspected periodically. The inspection should
include the following checks: 1 through 8.
Warning
The voltages indenergized equipment can cause severed personal injury or
death. Before inspecting the circuit breaker in an electrical system, make sure
the circuit breaker is switched to the off position and that there is no voltage
present where work is to be performed. Special attention should be paid to
reverse feed applications to ensure no voltage is present.
CAUTION
Some commercial cleaning agents will damage the Nameplates or molded
parts. Make sure that cleaning agents or solvents used to clean the circuit
breaker are suitable for the job.
1. Remove dust, dirt, soot, grease or moisture from the surface of the circuit breaker
using a lint-free dry cloth, brush or vacuum cleaner. Do not blow debris into circuit
breaker. If contamination is found, look for the source and eliminate the problem.
