How to Check AC Motor Winding with a Multimeter

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From fluid and solid material ventilation to ventilation, dependable AC motors are crucial to different industrial production processes. Did you know that AC motors drive designers to strive for energy savings and size reduction continuously?

This post will bring you to the definitive guide to AC winding motors, their composition, and the best way to check your AC motor winding. 

What is an AC Motor Winding?

AC motor windings are electric motors, also called coils. This is where they’re confined around a covered supple iron magnetic core to create magnetic poles though boosted with the current. Such windings are used as parts in different circuits, and they stand as a support to offer a magnetic field for multiple transformers, motors, and generators.

Keep in mind that windings are applied in the circuits based on their shape and dimensions. Even factors such as magnetic field capacity, insulation strength, inductance, and Q-factor show an impact on the coil winding’s shape. The categorization of coil windings is reliant on the type of the wounded coil and its geometry. 

Windings are composed of different coils wound from insulated copper or, in other cases, aluminum wire. Numerous strands of wire could be attached to a coil that will have several turns. The number of turns will vary depending on particular design requirements. 

Winding Failures You Will Come Across with AC Motor 

Are you wondering what causes your electric motor to malfunction? Hostile operating conditions, whether it be environmental, mechanical, or electrical, can substantially decrease the life of your electrical motor.  

Electric motors are often complex and difficult pieces of equipment. They can stop functioning for many different reasons. AC motors and DC motors can develop identical issues. Whether it’s from old age, wear and tear, or lack of maintenance, failures happen because of different causes.

Having a preemptive maintenance plan at hand is an excellent way to keep an eye on the health of your electric motor. The best thing here is that it helps you determine, assess, and resolve potential concerns that come over time and might necessitate repair services. 

When your electric motor requires some repairs, it’s normally because of winding problems. 

Remember that AC motor windings are one of the most typical sources of failure in electric motors. Further, they’re some of the most typical electric motor repair causes too. Stressful electrical, environmental, and mechanical operating conditions could all cause electric motor issues.

Difficulties with sub-optimal operating conditions could obstruct the power supply of the motor and, in turn, cause it to break down.  

Also, insulation glitches are another kind of AC motor winding failure, which could cause your motor to stop functioning. The winding insulation could involve a shorted phase-to-phase, a shorted turn-to-turn, or a shorted coil caused by:

  • contaminants
  • voltage surge
  • vibration
  • abrasion 

What’s more, thermal deterioration in your winding insulation—caused by too much heat—could also be a difficulty with AC motors. That’s because that can lead to uneven voltage caused by unstable power source loads or poor motor terminal connection. 

Don’t forget that bearing difficulties could also cause a lot of electric motor problems. Such issues take place with loose parts or when there’s friction between mechanical components. Shaft imbalance and misalignment can cause bearing difficulties in AC motor windings as well.  

Checking Your AC Motor Winding 

The procedure below evidently defines how motor windings are connected. It will also tell how you can check your winding and how values are recorded. Using a digital multimeter will help you with the calculations. The connections can also be performed as follows.

  1. Get your digital multimeter and attach the positive end (red probe) to the positive end of your AC motor windings. 
  1. In the same manner, the negative end of the terminal (normally in black color) is attached to the winding’s negative end. 
  1. The readings for your AC motor winding machine will be recorded, and such readings will be displayed on your multimeter screen. The corresponding resistance will be calculated in ohms.
  1. Now set your multimeter in ohms setting. Isolate the power supply and your AC motor. Put the meter on ohms, and the range will be in the order of two to three ohms. 

Do you receive a zero reading? Then it indicates there’s a short circuit in your AC motor winding. If there exists an open circuit, the range will go beyond 2K ohms or infinite. 

A great maintenance plan can help you find issues and stop an electric motor failure from winding problems and other mechanical concerns. Using precise diagnostic tools like a digital multimeter and software can help you get a better idea of where the issue lies in a motor so that you can make the necessary fixes.

Remember that motor problems could be complicated to find and repair without comprehensive technical expertise. You may need to go for a repair service to fix your AC motor’s problems.    

Final Thoughts

AC motor testing is crucial as when your motors malfunction, testing can determine problems that will then help avoid further failure. 

Now you should understand more about how the AC motor winding is made and what they’re made of. Essentially, the raw material utilized for both the rectangular and circular wire is either copper or aluminum. 

A lot of motor winding wire is composed of copper. Meanwhile, rectangular wires are made from the extrusion process where a wire rod is pushed through a die to get its final form. For round copper wires they get their form after numerous stages of cold drawing. 

To sum up, these windings are more critical in electric machines. That’s why they should be properly picked and executed. Numerous factors should be considered to determine the best quality, such as insulation, resistivity, the efficacy of the wire, life period, and more. 

There you have it! We hope you find this guide informative, educational, and helpful. You can now easily check your AC motor winding with a multimeter with the help of this guide. In case you forget any of the steps mentioned, feel free to visit this post again, so you’re well guided.

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