Why do Induction Motors Fail?

Why do motors fail?

Like all other industrial equipment, electric motors too have a predetermined lifespan ranging from 30,000 to 40,000 hours of operation. Obviously, this is dependent on proper maintenance without which they are going to fail much earlier. Understanding the top causes and preventive measures for motor failures will give your motor a longer service life.

"Keep the motor as cool as possible. Ensuring the operating environment is kept cool will help prevent breakdowns"

1. Electrical Overload

When current excessive than the design current flows through the motor windings electrical overload is caused. The motor in this case is unable to carry the excess current efficiently and safely and results in over-current. This is usually caused by a low supply voltage, resulting in the motor drawing more current to maintain its torque. Other reasons can be short circuited conductors or excessive voltage supply.

Solution:

Electrical overload can be prevented by installing effective over-current protection which will detect over-current and interrupt supply.

2. Low Resistance

One of the most common cause of motor failure is Low Resistance. This is caused by the degradation of the insulation windings due to physical damage, corrosion and overheating leading to insufficient isolation between conductors or motor windings which results in leakages and short circuits and eventually motor failures.

Solution:

Insulation should be regularly inspected for signs of wear and replaced before low resistance causes the failure.

3. Over-Heating

Almost half of the insulating failures in motors occur due to overheating. Overheating is caused by poor power quality or high ambient environment. The thumb rule states, for every 10oC rise in motor temperature, the insulation life is reduced by 50%.

Solution:

Keep the motor as cool as possible. Ensuring the operating environment is kept cool will help prevent breakdowns.

4. Contamination

Another leading cause of motor failure is contamination from dust, dirt and chemicals. Foreign bodies that find their way inside motors can dent bearing raceways and balls, leading to high levels of vibration. These foreign bodies sometimes block the cooling fan thus limiting the motors’ ability to regulate its temperature and increasing the likelihood of overheating.

Solution:

Keep work areas, tools and fixtures as clean as possible to help eliminate the chance of contamination entering the motor. Also, when laying out the workspace, try to position motors away from machines which produce large amounts of contaminants.

5. Vibration

Another major cause of premature motor failure is the abnormal vibration. Usually, vibration is caused by positioning the motor on an uneven or unstable surface. Other causes for vibration are loose bearings, misalignment or corrosion.

Solution:

Motors should be checked regularly for vibration using tools such as vibration analyzers, sensors etc. If vibration persists, consider calling in a specialist to inspect the motor.

IoT Condition Monitoring for Low Voltage Motors

A great way to improve motor service life and reliability is to monitor the live conditions of the motor. With advancement in Internet of Things, a huge breakthrough has been achieved in bringing condition monitoring systems for low voltage motors. The smart sensors for motors are economical to purchase and provide monitoring data for critical parameters like vibrations, misalignment, temperature and humidity, bearing conditions among other metrics.

Related: Harnessing power of IoT to cut motor downtime.

To know more about how you can benefit from IoT sensors, get in touch with us today.