- Joined
- Apr 28, 2018
- Messages
- 6
I am hoping there are one or two here on the forum that are wise in the ways of tool restoration when the electric motor is needing some love.
Summary: This electric motor was known to be in working condition a few months ago. Now, when it is powered on it sits and hums. Not good. I suspected the start capacitor. I tried replacing the start capacitor and that did not work. I need some advice on what to try next.
Background: I am setting up shop for the first time to spend some time with my son and learn something together. I was given a piece of machinery that I have tried to restore to working order. And for a while it did work just fine. Without notice, the motor would not spin up and simply hums. Not surprisingly, the imported machine has a motor that is clearly marked Made in China. I say that up front to get it out of the way and ask that people hold their opinions on such. The way I figure it, I was given some tools and beggars can't be choosers. That said, I don't expect any manufacturer support or even OEM parts to be available. Shoot, there aren't even manufacturer markings or model numbers noted.
Troubleshooting: When the machine would not start, I quickly powered it off and checked the obvious things like an obstruction, seized bearings, burned up windings, etc. Nothing to see there--all look good. While I had the motor housing open, I checked the centrifugal switch and it tested fine for continuity, moved smoothly and the contacts looked clean. This 110-125v, single phase, 12 amp motor only has a start capacitor. I check the start capacitor for tell tale signs that is was bad. It looked fine on the outside but this does not rule out the start capacitor being bad. I then tried giving the motor a swift spin while simultaneously powering the motor up to see if I could get it to spin on its own. The result: no go. So, being at the bottom of my bag of tricks, I resorted to looking for a replacement start capacitor as an obvious next step that was relatively cheap.
What I bought: Looking at the start capacitor, the markings are not super helpful or clear. I first read it as 35 or 35.0 mfd but, to the best of my knowledge, start capacitors for 110-125v 60Hz motors should be rated greater than 70 mfd. So, I interpreted the markings to mean 350 mfd. I looked high and low for one that matched exactly and had no luck. So I ended up with the closest thing I could find...a 340-408 mfd 110-125v start capacitor. I was pretty excited to hook it up and give a try. Sadly, the result was the same--humming and no rotation. My thought process brings me to believe that I might have something wrong with the start capacitor sizing but what I have read stated that what I chose should have worked.
Can one of you confirm if the 340-408 mfd range-rated start capacitor should (or should not) work as a functional replacement for the original capacitor?
If you have other suggestions for troubleshooting I would appreciate hearing it.
Summary: This electric motor was known to be in working condition a few months ago. Now, when it is powered on it sits and hums. Not good. I suspected the start capacitor. I tried replacing the start capacitor and that did not work. I need some advice on what to try next.
Background: I am setting up shop for the first time to spend some time with my son and learn something together. I was given a piece of machinery that I have tried to restore to working order. And for a while it did work just fine. Without notice, the motor would not spin up and simply hums. Not surprisingly, the imported machine has a motor that is clearly marked Made in China. I say that up front to get it out of the way and ask that people hold their opinions on such. The way I figure it, I was given some tools and beggars can't be choosers. That said, I don't expect any manufacturer support or even OEM parts to be available. Shoot, there aren't even manufacturer markings or model numbers noted.
Troubleshooting: When the machine would not start, I quickly powered it off and checked the obvious things like an obstruction, seized bearings, burned up windings, etc. Nothing to see there--all look good. While I had the motor housing open, I checked the centrifugal switch and it tested fine for continuity, moved smoothly and the contacts looked clean. This 110-125v, single phase, 12 amp motor only has a start capacitor. I check the start capacitor for tell tale signs that is was bad. It looked fine on the outside but this does not rule out the start capacitor being bad. I then tried giving the motor a swift spin while simultaneously powering the motor up to see if I could get it to spin on its own. The result: no go. So, being at the bottom of my bag of tricks, I resorted to looking for a replacement start capacitor as an obvious next step that was relatively cheap.
What I bought: Looking at the start capacitor, the markings are not super helpful or clear. I first read it as 35 or 35.0 mfd but, to the best of my knowledge, start capacitors for 110-125v 60Hz motors should be rated greater than 70 mfd. So, I interpreted the markings to mean 350 mfd. I looked high and low for one that matched exactly and had no luck. So I ended up with the closest thing I could find...a 340-408 mfd 110-125v start capacitor. I was pretty excited to hook it up and give a try. Sadly, the result was the same--humming and no rotation. My thought process brings me to believe that I might have something wrong with the start capacitor sizing but what I have read stated that what I chose should have worked.
Can one of you confirm if the 340-408 mfd range-rated start capacitor should (or should not) work as a functional replacement for the original capacitor?
If you have other suggestions for troubleshooting I would appreciate hearing it.