Ask John

cropped-vintage-1915-century-brass-tag-electric-motor-img1.jpgWhat exactly IS an electric motor?

In the most basic terms, an electric motor is a machine that can convert electrical energy into mechanical energy by using an electromagnet to create motion. (You can read a more detailed description of how an electric motor works in the link below.)

Electric motors are all around you. If you woke up and ground some coffee, whipped up a smoothie in your blender or used an electric razor or blow dryer this morning, an electric motor helped you start your day. One helped transport you to work if you started your car, and may have even gotten you all the way there if you took a streetcar or drive an all-electric or hybrid vehicle!

Electric motors enable us to clean house (vacuums), preserve food (refrigerators, freezers), wash our clothes (washers, dryers), move water (well and fountain pumps), keep things cool (fans), run power tools (compressors, drills, saws) and manufacture things. There are literally thousands of industrial applications for electric motors.

They come in all sizes—from the tiny, simple motors in a child’s toy, to large industrial motors used in manufacturing. Some of the most powerful motors in the world drive the propellers on the Queen Elizabeth II cruise ship and run a wind tunnel at NASA’s Langley Research Center.

How does an electric motor work?

This link to HowStuffWorks has a great explanation. With moving pictures and everything.

John couldn’t have said it better himself!

When is it worth repairing a motor?

That can depend on a number of factors. Here are some things to consider:

  1. What kind of motor is it? Large, expensive or highly specialized motors are almost always cheaper to repair than to replace.
  2. Is time of the essence? Can you get a new motor right away, or will it be faster to repair it than to order a replacement? If the well pump or other critical piece of equipment goes down, repairing it now may be the best way to get it back up and running quickly.
  3. Is the rest of the machine the motor powers in good shape? If the motor’s the only thing wrong with a $200 compressor, or a $2000 treadmill, getting it fixed makes sense.
  4. How attached are you to the thing the motor powers? If you take pride and pleasure in still using your very first table saw or your grandmother’s classic 1952 Singer sewing machine, if you just love an all-metal antique fan, or if that stand mixer in a now-discontinued color went perfectly in your kitchen, why not repair or replace the motor and give that object many more years of useful life (assuming number 3 applies, of course).
  5. Is the cost of the motor repair less than the cost of a new one? Fixing a $150 sump pump for the price of a new switch and a little labor? Totally worth it. Doing a complete motor rebuild on a $30 blender? Probably not (unless number 4 applies).

We’re always happy to take a look and give you a free estimate on repair costs to help you decide.

Is there really a John?



Got a burning question about electric motors? Scroll down to ask John.

8 thoughts on “Ask John

  1. I have a 24volt motor for the bow thruster on my boat. Not sure the motor is the sou
    rce of the problem but maybe you could check it out for me if I brought it in. Then if it is the motor maybe you could repair it?

    • Hi Scott
      Yes, if you can bring it in, we’ll check it out and let you know what’s going on with the motor.
      We’re here 8 to 5 Monday through Friday.
      Thanks for checking out the website.

  2. I think when dealing with choosing between a motor repair and a motor replacement, it’s necessary to look at the costs like you mentioned. Sometimes the repair is less than the replacement price, but it’s important to look at your choices before you make a final decision. If my motor ever breaks, I’ll keep all this information in mind before I make a final decision.

  3. Hi, you may not be able to help me, but here goes, do you work on refrigerator compressors. I bought a used one off craigslist a few days ago, but will not fire it up because when I was shoving it up the stairs I saw on the compressor and all down its side white plumbers Puddy, yeah I asked Sears but they said junk it and buy from us. Well I need a honest opinion. First I have never seen that on a compressor, and my worry is I do not want to be so cheap I kill my tenants and burn the house down my mommy built with her own hands. Do you think its safe? I saw somewhere on the net, that sometimes that Puddy is under the drip pan and it transfers heat from the compressor to dry out the drip pan of water, but I am aware that the fire in London that killed all those people last year was from a compressor gone bad. I also youtube a zillion images and not one goopy compressor. So, what say you and thanks.

    • Hi Ella.
      It’s really hard to say without seeing the refrigerator compressor, but it sounds like it’s been tampered with. That’s the only reason we could see for the putty. Even if the putty itself won’t cause an issue, it does indicate that someone’s had it apart and messed with the compressor–maybe tried to fix it before. Even if they got it running, there’s no guarantee they knew what they were doing.
      I would play it safe and not use the refrigerator. Bummer, I know, but better safe then sorry–especially if you are providing it for tenants in a place that matters to you.
      If you look for another used one on craigslist, be sure to inspect the outside thoroughly for any signs that someone’s taken it apart before. And ask the person selling it to plug it in so you can hear it run for a while.
      All the best.

  4. Hi John , I have marathon motor that powers a small pump , I have it disassembled, I would like to bring it to your shop, and have it checked to see if it’s worth fixing or give it’s last rights, curios of the costs for the first look,

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