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WEG Molded Case Circuit Breakers - User’s Manual

9

Push-to-trip 

button

Handle position indicator color

Red

ON

ON

ON

-

White

TRIP

TRIP

TRIP

International  
symbols

Thermal-magnetic 
Trip Unit Adjustment 
Button (3 places)

-

Green

OFF (reset)

OFF  
(reset)

-

Figure 7:

 circuit breaker manual controls

3.2.  CIRCUIT BREAKER RESET

After an automatic or accessory initiated trip, or a manual Push-to-Trip operation, 
the circuit breaker is reset by moving the circuit breaker handle to the extreme OFF
position.

NOTICE

In the event of a thermal trip in a thermal magnetic type trip unit, the circuit breaker 
cannot be reset until the thermal element in the trip unit cools.

No circuit breaker should be reclosed until the cause of trip is known and the situation 
rectified.

3.3.  PUSH-TO-TRIP BUTTON

The PUSH-TO-TRIP button checks the circuit breaker tripping function and is 
used to periodically exercise the operating mechanism in thermal-magnetic trip 
units. The button is designed to be operated by a small screwdriver.

3.4.  THERMAL-MAGNETIC TRIP UNIT ADJUSTMENT

The magnetic element of each pole of the trip unit can be adjusted by rotating the 
adjustment buttons on the front face 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 (In) (see Figure 8) To adjust the setting, rotate each but
ton clockwise until arrow on button points to desired setting.

Summary of Contents for LT1 UBW250

Page 1: ...Motors Automation Energy Transmission Distribution Coatings User s Manual WEG Molded Case Circuit Breakers UBW250...

Page 2: ...recommendations and information contained herein are based on WEG experience and judgment but should not be considered to be all inclusive or covering every application or circumstance which may aris...

Page 3: ...n Fixed thermal Adjustable thermal1 Adjustable magnetic of ln 2 UBW250 250 200 250 5 to 10 Table 1 available trip unit ratings Notes 1 Not UL listed 2 For adjustable thermal trip units the magnetic se...

Page 4: ...ternal accessories be installed at the factory in this type of circuit breaker For hardware conversion kits and handle mechanisms required to replace existing WEG circuit breakers If required internal...

Page 5: ...Care should be taken every time a thread forming screw is used to ensure the screw starts in the original threads Damaged threads can result in improper circuit breaker cover retention 4 Install cove...

Page 6: ...d equipment can cause death or severe personal injury Before mounting the circuit breaker in an electrical system make sure there is no voltage present where work is to be per formed Special attention...

Page 7: ...rcuit breaker handle Figure 6 circuit breaker escutcheon dimensions b If circuit breaker includes factory or field installed internal accessories make sure that accessory wiring can be reached when th...

Page 8: ...t breaker nameplate Terminal catalog number Terminal material body Screw head type AWG wire range Metric wire range Wire type Torque value Lb in N m LT1 UBW250 Stainless steel Socket 4 350 MCM 25 185...

Page 9: ...ermal element in the trip unit cools No circuit breaker should be reclosed until the cause of trip is known and the situation rectified 3 3 PUSH TO TRIP BUTTON The PUSH TO TRIP button checks the circu...

Page 10: ...aid to reverse feed applications to ensure no voltage is present CAUTION Make sure that cleaning agents or solvents used to clean the circuit breaker are suitable for the job Some commercial cleaning...

Page 11: ...the connections If there is evidence of overheating terminations should be cleaned or replaced Before reenergizing the circuit breaker all terminations and cable should be refurbished to the conditio...

Page 12: ...hone 233 30 2766490 info zestghana com gh INDIA Bangalore Karnataka Phone 91 80 41282007 info in weg net Hosur Tamil Nadu Phone 91 4344 301577 info in weg net ITALY Cinisello Balsamo Milano Phone 39 2...

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