What Causes an Electric Motor to Hum and not work

One of the most common machines is those that are powered by electric motors. At times, however, these motors can display a mystifying phenomenon — they hum but they don’t work. This can lead to a frustrating and puzzling scenario leaving machine operators and maintenance staff baffled.

• Table of Contents

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  Introduction 

• Reasons an Electric Motor Hums but does not work?

• How to Diagnose and Repair?

• Safety Measures

• Useful Tips 

• Conclusion

Introduction

What is a HUMMING sound? Before knowing the causes of a humming sound, let’s understand about it. The humming sound is usually caused by the interaction between the magnetic field produced by the motor and its surroundings.

Whenever we supply power to an electric motor, a magnetic field is produced in its windings which generates an EMF (Electromotive-force). The EMF causes the motor to spin, but it does generate a humming or buzzing sound.

Reasons an Electric Motor Hums but Doesn’t Work?

Now that we’ve dealt with the general nature of the humming sound, here are some possible reasons an electric motor might hum but not work.

Loose or Faulty Connections

 One of the most frequent causes for a humming motor is loose or faulty connections. Also look for any damaged, corroded, or worn wiring or connectors on the motor terminals. Tighten the loose connections and faulty components or replace them as and when needed.

Mistaken Motor Wiring

Mistaken motor wiring can create a humming motor without rotation. Ensure that the motor wiring is correct according to the manufacturer’s specifications and refer to the wiring diagram if needed.

Low Voltage or Power Supply Issues

If there are low voltage or power supply issues, one may not hear the electric motor rotating but hear a humming sound. Verify that the voltage from the power supply is up to industry standards through the use of Volt-ammeters, etc.

Motor Bearing Failure

Worn-out or failed bearings in the motor can result in the motor humming but failing to turn. Check the bearings of the motor and replace them if necessary.

Motor Windings or Stator Failure

In cases of motor windings or stator failure, the motor may hum but fail to spin. Check for visual damage/wear on the motor windings, and stator and replace if needed.

Capacitive Errors

Some electrical motors use capacitors to control motor speed or direction. If the motor hums but does not turn it may also be because the capacitors have failed or are improperly sized. Now confirm the capacitor rating and condition, and it will have to be replaced.

Overheating

Poor ventilation can cause overheating. Monitor the motor temperature and check that it is within the limits defined by the manufacturer. 

Mechanical Blockages

Mechanical blockages, like a stuck or jammed mechanical part, can stop the electric motor from rotating but not make weird humming. Inspect the machine’s mechanics and remove debris. 

How to Diagnose and Repair?

Turns Off the Power

Before performing a treadmill motor repair, always turn off the power to the electric motor. 

Check for Visible Damage

 Look for any signs of damage, wear, or corrosion on the motor. 

Check Connections and Wiring

 Ensure all connections and wiring are secure and according to the manufacturer’s specifications.

Check the Motor

Inspect the electric motor’s windings, bearings, and other components with a multimeter for damage or wear. 

Repair/Replace Damaged Parts

Repair or replace any worn or damaged parts, but the bearings, windings, and capacitors are the most common suspects.

Reassemble and Test

 Assemble the motor back and check if it is working properly.

• Safety Measures 

Ensure that no voltage is applied to the motor to avoid the electrical shock. 

Make sure the power is completely disconnected from the motor. Do not burn yourself and prevent electrical shock, so make sure the motor is cool to your touch. Personal protective equipment (PPE) like safety glasses, insulated gloves, and dust masks should be used.  

Detach the motor housing.

Unscrew the screws or bolts that hold the electric motor housing in place with a screwdriver or wrench. Carefully slide the housing away from the motor. You will also find the parts needed for your circuit, as well as the caution issued for that input in user manuals. Disconnect the motor bearings: Remove the motor bearings using a bearing puller or a screwdriver. Do not damage bearings and motor shafts. Inspect and clean the motor. Check the motor winding. Visually, check the motor windings for any damage, signs of wear, or overheating. 

Then use compressed air or a soft bristle brush to clean the motor.

To join the motor, reinstall the motor bearings with a bearing installer or screwdriver. Finally, seat them well and strap them in. Reattach any electrical connections to the motor, including the power cables, sensors, and control wires. Use a screwdriver or wench to reassemble the motor housing. Make sure all screws or bolts are tightened.

Ensure the electric motor is correctly assembled. 

Make sure all components are assembled correctly and are properly secured. Once the capacitor is replaced, reconnect it and the power supply, and test the motor to see if it is working properly. 

Now that a humming motor is almost an old hat, opening and siding a humming motor is a blissful hair-raising activity. If any of this is beyond your capabilities, it’s safer to call in a pro, such as an electrician or a motor repair technician.

Make sure the motor is correctly locked out or tagged out to avoid extra start-ups. Isolate the Power Supply: Before making any repairs, ensure that you have disconnected the power supply to the motor.

Use a multimeter and always confirm the absence of voltage with a multimeter before touching electrical components. Electric parts or wires should not be touched with bare hands.

Make sure that the electric motor is tightly enough secured to a workbench so that it can’t move or fall off. 

Use appropriate tools like wrenches, pliers, and screwdrivers to prevent damaging the motor or injuring yourself. Do not over-tighten bolts, screws, or other fasteners as doing so can damage the motor or will cause injuries. Be careful of sharp edges or points on the motor or tools that could lead to cuts or puncture wounds. To avoid breathing in toxic vapors or particles, work in a well-ventilated area.

There should be proper disposal of hazardous materials (used oil, solvents, electrical components, etc. Place a fire extinguisher close by, and remove any flammable items from the area where you are working. Refer to the motor’s manual or manufacturer’s guidelines for any specific safety protocols.

A Tip to Avoid Electrical and Mechanical Issues During Car Repair is to ensure you follow local regulations.

 Ensure you are compliant and up to date with local regulations and guidelines for electrical and mechanical repairs. By adhering to these precautions, you’re able to reduce the dangers of fixing a humming motor and maintain a secure workspace.

Conclusion 

In summary, a humming electric motor that doesn’t work can be frustrating and puzzling. But, knowing why it happens and following the troubleshooting and repair steps described in this article, you will be able to detect and resolve the problem. And, as always, make sure to follow any appropriate safety measures when working on electric motors, and consult the manufacturer or a qualified electrician if you have any questions about any step of the repair.