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5 Tips For Maintaining Electric Motors

In this article, we will go over five points on how to keep your electric motors running properly and help extend the life expectancy of your motors. We will go over lubrication, bearing inspection, checking your rotor and stator, motor mount, and how important keeping records are. Follow these and you should see sustained performance and reliability with your motors.

Lubrication

In this section, we will walk you through making sure the bearings on your electric motor are properly lubricated. Without proper lubrication, it will cause the bearings to wear out prematurely. Here are a few pointers on how to lubricate your electric motor’s bearings.

1. Don’t over lubricate your bearings. Over lubrication can cause the grease or oil to get into the windings. This will cause the insulation to deteriorate around the winding causing arcing and shorting inside the motor to the case. This will cause excessive heat and wear on the rotor and stator as well.

2. Always use the lubricant designated by the manufacturer. The use of other lubricants can do damage to the bearings, causing them to wear faster or unevenly.

3. Consult your manual or the manufacturer’s website to find out the proper interval for lubrication. Lubricating too often or not lubricating often enough could also cause premature wear in your bearings if under lubricated or degradation of the insulation around the winding if over lubricated.

Bearing Failures

Bearing failures are one of the most common and easiest problems to prevent. If your bearings fail, there are multiple things that could go wrong with your electric motor. This section will go over how to inspect the bearings on your motor and prevent unnecessary wear to the bearings.

1. Make sure your load attached to your motor is aligned properly. Misaligned loads can throw the rotation off-balance, straining one or both bearings.

2. Keep the motor clean of contaminants and moisture. You may have to blow out the motor every so often to keep it free of moisture and small particles that could work their way into the bearings.

3. Take temperature readings occasionally to monitor how warm or hot the bearings get. Compare those readings to the safe temperature range provided by the manufacturer. If the bearings are getting too hot, stop using the motor, let it cool down, and promptly inspect the bearings for damage or contaminants.

4. If you hear any abnormal sounds coming from your motor, you can use a stethoscope to better identify what part of the motor the sound is coming from. It is also preventative maintenance to just periodically use the stethoscope to listen for any abnormal sounds coming from the motor so you can address the issue before it does any further damage to the other components of the motor.

5. Check oil rings (if applicable) and keep an eye out for excessive shaft play. Excessive play in the shaft is a good indicator that you have a bearing that is defective or will be soon.

Rotor and Stator

The rotor and stator are the heart of your electric motor. Without these components working properly, your motor will function very poorly or not at all. These are a few pointers to help you make sure all is well with the rotor and stator.

1. Use a feeler gauge to check the gap between the stator and rotor for equal clearance all the way around.

2. Record the gap sizes at the top, bottom, and both sides at each end.

3. Compare to any previous readings you may have or to manufacturer’s gap specifications.

4. Any differences are a good indication that there is excess wear in your bearings and it may be time to replace those bearings.

Motor Mount

It is wise to inspect your motor mount on occasion to make sure it is still in good condition. A faulty motor mount can do damage internally to your motor and may even have an adverse effect on your load as well.

1. Check the mounting bolts for proper tightness. If they are loose, tighten them up until there isn’t any play in the mounts.

2. Make sure there isn’t any play between the mounts, whether it is between the plate and rubber isolation feet or between the plate and hard mount.

3. Inspect the motor plate for any warping or cracks that could cause unnecessary flexing under load or at startup.

4. If it is mounted to concrete, check the concrete for cracking or chipping/erosion around the anchor bolts.

5. Repair anything on an as found basis to extend the life of the motor.

Record Everything

It is essential that records be kept for your machines. It makes maintaining your machines that much easier and minimizes downtime.

1. Document everything! That way you know exactly what is going on with your motors.

2. If there are any symptoms that repeat, it will be easier to solve the problem the next time it occurs.

3. Keeping records will also help figure out the common problems so you can have backup parts if needed.

4. You might even notice a pattern so you can preemptively address a problem pattern.
Use this as a guide when it comes to maintaining your electric motors. By following the items in each of the 5 sections above, you should be able to optimize the performance and prolong the life of your motors.

11 thoughts on “5 Tips For Maintaining Electric Motors

  • Kevin M

    February 16, 2017 at 2:57 am

    We have a 40 hp motor for our cnc lathe . Aren’t these motors sealed? We received no service manual with our motor

    • Chad C

      December 26, 2017 at 10:10 pm

      Yes they’re sealed. No one ever lubricates the motor bearing on any CNC I’ve ever seen. Maybe on very large ones but generally the sealed bearings in those motors will last years and years as long as you’ve got the belts tensioned properly.

  • Wayne Campeau

    February 16, 2017 at 1:33 pm

    I worked in motor repair shop 4 year’s and the horror stories I could TELL you.
    Bearing lubrication, be consistent in grease use! Many Types of grease’s are not compatible
    Good Post I must say and EASA is great source of information too!

    • Everett Plummer

      April 23, 2018 at 8:59 pm

      We got a flaming motor in one time from a place that made Vette parts. It was a large open motor that was solid with grease and grinding dust from the FRP parts. They had put out the fire at the plant, but driving an open motor in the back of an open truck, reignited the grease. A passing motorcyclist was distracted and wreaked. We got the hose and extinguishers out. They must have greased it daily with more than one pump.

  • Steven

    October 11, 2018 at 12:37 pm

    Very well explained here about to maintain the electric motors. These are the major step should be taken by those working in this industry. Following these basic steps, you can avoid any major breakdown.

  • Richard

    March 13, 2019 at 3:55 am

    Most motors on the new electric motors don’t need greased anymore because there sealed bearings you have to check the owner’s manual.

  • Dutch

    November 23, 2019 at 4:02 am

    grounding rings are a must if motors are on a vfd

  • Robert

    January 3, 2020 at 4:02 pm

    I cant believe I just read an article on how to maintain electric motors, and never once did it mention to check amp draw under full load.

  • Allen Jackson

    February 27, 2020 at 12:01 pm

    I cannot find any information on how to grease my GE electric motor. It is a 1968 vintage 3 H.P. , 220 VAC Single Phase motor ( Used on a Wayne Air Compressor ). It has ball bearing at both ends. It has 1/8″ – 27 screws at both ends, one at 12 O’Clock and one at 6 O’ Clock where the shaft exits the motor in the front. The back is the same EXCEPT the holes are at 3 O’ Clock and 9 O’ Clock positions. Looks to me as if one could install a Zerk fitting to grease it. I removed the screws and did find a very small amount of Yellow / Orange grease in the holes. I THINK, ( from what I have seen on the internet ) that it should be greased at the top hole until the old grease flows out through the bottom hole ?? Again, I am only guessing, and if this is true HOW MUCH GREASE SHOUL BE USED ?? Should the motor be running while you grease it ?? Any help would be GREATLY appreciated.

    Al

    • Sarah

      May 26, 2020 at 3:07 pm

      Hi Allen, thanks for reaching out!

      Typically there are grease zerks / fittings on the motor themselves and that is where you should insert the needed grease. If you do not have any I would recommend reaching out to the manufacturer of the motor to verify if it even needs greasing. Some motors come with double shielded bearings where they then do not require any greasing. Also, I would verify with the manufacturer the type of grease you should use for your specific motor.

  • ปั๊มไลค์

    May 29, 2020 at 2:41 pm

    Like!! Great article post.Really thank you! Really Cool.

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