7-7. Overload Protection

Tools Needed:

3/8 in

5

4

3

YStop engine.

.When a circuit breaker or fuse opens, it usually indicates a more serious problem exists. Contact a Factory Authorized Service Agent.

1 Circuit Breaker CB5

CB5 protects the 24 volt ac output to Remote 14 receptacle RC1. If CB5 opens, 24 volt ac output to RC1 stops.

2 Circuit Breaker CB6

CB6 protects the 115 volt ac output to Remote 14 receptacle RC1. If CB6 opens, 115 volt ac output to RC1 stops.

Press button to reset breaker. 3 Fuse F6 (See Parts List)

F6 protects the engine wiring sys- tem from overload. If F6 opens, engine will not crank.

4Fuse F1 (See Parts List)

5Fuse F2 (See Parts List)

Remove side panel.

F1 protects the exciter excitation winding from overload. If F1 opens, weld and auxiliary power output stops.

F2 protects the stator winding from overload. If F2 opens, weld output stops. Auxiliary power will still be available.

Replace any open fuses. Reinstall cover before operating unit.

1

2

ST-801 945-C / Ref. ST-189 925-A

7-8. Troubleshooting

A. Welding

Trouble

Remedy

 

 

No weld output.

Check control settings.

 

 

 

Check weld connections.

 

 

 

Disconnect equipment from auxiliary power receptacles during start-up.

 

 

 

Place Output (Contactor) switch in On position, or move switch to Remote 14 position and connect

 

remote contactor to Remote 14 receptacle RC1 (see Sections 4-8 and 5-1).

 

 

 

Check fuses F1 and F2, and replace if necessary (see Section 7-7).

 

 

 

Have Factory Authorized Service Agent check brushes, slip rings, and field current control board PC2.

 

 

OM-486 Page 27

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Miller Electric 251 NT manual Overload Protection, Troubleshooting, Welding, Trouble Remedy
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251 NT specifications

The Miller Electric 251 NT is a highly regarded multi-process welding machine known for its versatility and advanced features, making it an ideal choice for professionals in various industries. With its robust construction and user-friendly interface, the 251 NT provides an efficient solution for MIG, TIG, and Stick welding applications.

One of the main features of the Miller Electric 251 NT is its impressive output range, which allows for welding on a variety of materials and thicknesses. It delivers up to 250 amps of power, enabling users to tackle both thin and thick metals with ease. Additionally, the machine is equipped with an Auto-Set feature, which automatically adjusts the welding settings according to the material thickness and type. This eliminates the guesswork, significantly enhancing productivity and reducing setup time.

Another noteworthy aspect of the Miller Electric 251 NT is its inverter technology. This advanced technology provides a compact, lightweight design without compromising performance. Inverter technology allows for greater energy efficiency, resulting in reduced operational costs over time. The 251 NT also features a Duty Cycle of 60% at 250 amps, which means it can handle demanding tasks while maintaining optimal performance.

The Miller Electric 251 NT is designed with user convenience in mind. The intuitive digital display offers clear visibility of the settings, allowing welders to make quick adjustments. Furthermore, the machine includes a built-in memory function to store frequently used parameters, enhancing workflow efficiency.

Safety is a key component of the 251 NT's design. It comes equipped with various safety features, including overload protection and a thermal overload warning system. These features ensure that the machine operates within safe limits, minimizing the risk of damage and ensuring longevity.

In terms of portability, the Miller Electric 251 NT's lightweight design and integrated handle make it easy to transport between job sites. The durable housing protects the internal components, making it suitable for rigorous use in demanding environments.

Overall, the Miller Electric 251 NT offers a combination of power, flexibility, and ease of use, making it a top choice for welders looking to enhance their capabilities across multiple welding processes. Whether in a professional shop or on a construction site, the 251 NT stands out as a reliable and efficient welding solution.
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