10 Common DC Motor Failures That You Should Know!

DC motors are some of the best tools that you can use for a wide variety of applications. However, like other electric motors, DC motor failure is no different. Whether it’s due to motor windings or other factors, there are a few common DC motor failures that you should know about.

Common DC Motor Failures

When your line experiences an electric motor failure, you might wonder what the cause is or how you can prevent motor failure in the future. Below are some of the most common causes of motor failures and what you can do to prevent them.

1) Overload of Motor Windings

Electrical shorts are one of the most common causes of motor failures. When the motor windings are overloaded, they can create an electrical short, which can cause the motor to overheat and eventually fail.

To prevent this type of failure, make sure that the motor is not overloaded and that the wiring is in good condition. A good solution that can help is to use adequate DC supply voltage or add overcurrent prevention. This can help prevent motor overload and electrical shorts.

2) Loose Windings

Another common cause of motor failure is loose windings. When the windings are not properly tightened, they can come loose and cause the motor to vibrate. Eventually, motor failure is imminent.

To prevent this, make sure that the windings are properly tightened and check to ensure there is no excessive vibration. To tighten the windings, you can use a torque wrench or other similar tool.

3) Dirty Commutators

Commutators are an essential part of DC motors, and they need to be kept clean to function properly. Dirty commutators can cause the motor to run inefficiently and eventually fail.

To prevent this, make sure to regularly clean the commutators with a brush or other cleaning method.

4) Bad Bearings

Bad bearings are another common cause of motor failure. When the bearings are worn out, they can cause the motor to vibrate and eventually fail.

To prevent this, make sure to regularly check the bearings for wear and tear. If the bearings are worn out, they will need to be replaced.

5) Degraded Winding Insulation Breakdown

Unfortunately, over time the insulation around the motor windings can degrade and break down. When this happens, it can cause an electrical short, which can lead to motor failure.

The best way to prevent this is to regularly check the condition of the winding insulation and replace it if necessary. Some things that can lead to motor windings degrading include excessive current flow due to corrosion in the windings. Debris and moisture form extremely corrosive substances, while heat and physical damage can also lead to premature wear. The best way to prevent costly downtime and improve insulation life is to inspect the insulation regularly.

6) Motor Bearing Failure

Bearing failure is another common cause of motor failure. When the bearings fail, they can cause the motor to overheat, which will eventually lead to failure.

To prevent bearing failure, make sure that the bearings are properly lubricated. Improper lubrication or under-lubrication can cause the bearings to fail. In addition, make sure that the bearings are not overloaded and that they are not subject to excessive vibration.

7) Excessive Vibration

Excessive vibration is another common cause of motor failure. When the motor is subject to excessive vibration, it can cause the bearings to fail or the windings to come loose. The bearing housing can also be damaged, which can lead to failure.

To prevent excessive vibration, make sure that the motor is properly mounted and pay attention to rattling noises.

8) Debris and Contamination

Debris and contamination are two more common causes of failures. When the motor is contaminated with dirt, dust, or other foreign objects, it can cause the bearings to fail or the windings to come loose.

In addition, the cooling fan that is used to cool the motor can become clogged with debris, which can cause the motor to overheat and eventually fail.

The best way to prevent this is to keep the area around the motor clean and free of debris. In addition, make sure that the cooling fan is clean and unobstructed. It’s always best to plan for regular maintenance to avoid issues such as these.

9) Improper Installation

Not all motor failures are due to problems with the motor itself. In some cases, the failure is due to improper installation.

For example, if the motor does not have the correct alignment, it can cause excessive vibration, which can lead to bearing failure or damage to the winding housing.

In addition, if the motor is not properly supported, it can also cause poor power quality, which can lead to motor failure.

Make sure that the motor is properly installed and that it is aligned correctly. Also, make sure that the motor is properly supported to avoid power quality problems.

10) Not Following Manufacturer’s Instructions

Not following the manufacturer’s instructions is another common cause of failures. When the motor is not used or installed properly, it can void the warranty and cause the motor to fail.

In addition, putting extra stress can lead to insufficient torque, which can cause the motor to overload and eventually fail.

Make sure to follow the manufacturer’s instructions when installing or using the motor. In addition, make sure that the motor is not overloaded to avoid failure.

This is an example of a Manufacturer’s Instructions which are taken from AssunMotor’s AM-BL1632AN Series.

Common DC Motor Failures Statistics

While it might seem like there are many causes of motor failure, statistics show that most failures boil down to five common causes, which can help expound the list above.

Bearings

Faulty bearings are responsible for more than half (51%) of all motor failures. In order to prevent bearing failure, make sure that the bearings are properly lubricated and that they are not overloaded or subject to excessive vibration.

Windings

Corroded or degraded windings are responsible for about 16% of all motor failures. Faulty windings lead to electrical shorts, overheating, and damage. Never let your windings go without a proper inspection, and continue to check for physical damage.

External Causes

From operator errors to poor maintenance, weather extremes, and flooding, about 1 in 5 motor failures are due to external causes. While some of these events might be out of your control, the best way to prepare for success is to conduct proper maintenance on your DC motors as often as possible.

Other Causes

Problems with the rotor itself, motor shaft coupling (which is rare but can still lead to failures), and unknown causes make up the rest of the motor failures (10%). However, that doesn’t mean that you should overlook them during your regular maintenance checks.

Regular maintenance is the key to preventing motor failures, and by extension, downtime. By keeping on top of your DC motor’s health, you can avoid costly repairs and replacements, as well as maintain optimal operation.

Conclusion

Did you find this list of 10 common DC motor failures useful? Follow the tips outlined, such as ensuring you’re inspecting your motors and following manufacturer guidelines, to help extend the life of your motors and prevent costly motor repair. Share this list with your fellow industry professionals and check out Assunmotors for our line of DC motors (brushless, brushed & servo) that are coreless in design today!