Need Electric Motor help

[Bucksaw]

I have a knife grinder that runs on a 1/3hp 115v motor that died a few weeks ago. I need a 2x72, but the catch 22 is that I have no money until I sell some knives, but I cant sell knives until I get a grinder. So, Im going to attempt to get my current 2x42 going. Like I said, the motor is a 1/3 hp 115v motor, and it got to the point that it would not spin when turned on. It would hum, and occasionally it would spin if jump started with my hand, but it got to where it just hummed and would not spin at all.

I took it apart today to see if it had an external capacitor and when I found it, it was all swollen and had stuff expanded out of the case. So, I need a new capacitor. Problem now is that I cannot find anything on it as far as a part number or manufacturer, and the specs on the side don't seem to pull up a replacement. I also don't know much about electric motors or capacitors, so Im not sure if its a run capacitor or a start capacitor, or how to tell the difference. The specs are 16uF with a 5-10% tolerance, 250v. The closest I found was a 15uF with a 5% tolerance, 250v. My questions are;

1. How do you identify the difference in a run capacitor and a start capacitor?

2. Will 1uF make a difference?

[super_dave]

I doubt the motor has a run cap.
Make sure polarity is correct on the new cap and install it and give it a shot,

[175gr7.62]

Based on those numbers I would think that what you have is a run capacitor but you don't see them very often on 1/3hp motors. Start capacitors are normally up around 80-100 microfarads. Run capacitors have to be sized pretty closely, but i'm betting 1 microfarad on a 1/3 HP motor isn't going to mess up your phase shift enough to be of a concern.

[double bogey]

Voltage rating needs to be at least as high as original. Within 10% on mfd rating. you should be fine with a 15mfd cap. And it is a split capacitor motor, uses the same cap to start and run.

[Texas Tracker]

Take your capacitor to a electrical supply house and they can match it by looking at it.

[poisonivie]

Based on those numbers I would think that what you have is a run capacitor but you don't see them very often on 1/3hp motors. Start capacitors are normally up around 80-100 microfarads. Run capacitors have to be sized pretty closely, but i'm betting 1 microfarad on a 1/3 HP motor isn't going to mess up your phase shift enough to be of a concern.

I have no clue what he said but he sounded good saying it. Go with this!

[LonestarGent]

It doesn't say the cap size on the motor nameplate? Can you post pic of nameplate and cap?

[red]

i have 2 motors at the house, your welcome to one of them if we can get it from dfw to your side of the woods. i believe one is a 1/3hp and i believe the other is a 1/2hp. i can verify when i get to the house if you are interested.

[Texas Tracker]

i have 2 motors at the house, your welcome to one of them if we can get it from dfw to your side of the woods. i believe one is a 1/3hp and i believe the other is a 1/2hp. i can verify when i get to the house if you are interested.

This wright here is what makes TBH so great! ^^^^^^^^^^^^^^^^^

[Bucksaw]

i have 2 motors at the house, your welcome to one of them if we can get it from dfw to your side of the woods. i believe one is a 1/3hp and i believe the other is a 1/2hp. i can verify when i get to the house if you are interested.

Heck of a gesture bro. PM sent with an offer for a future knife as trade.

[Bucksaw]

SO what about voltage? I know it needs to be at least as high, but can I get one rated for higher voltage? I found a capacitor that is 16uF, but its over 400V rating. That should be OK right?

Also, are these things polar? The old one had 2 red wires, but the one I found online has a red and a black. Does it matter which direction they are wired in? IF so, How do I determine the polarity of my old one?

[60 Deluxe]

You have to buy the same or higher voltage. Don't worry about the nameplate on the motor not having the information, just shoot for finding a 16 but settle for a 15 or 17. you might find them at 250V, 330V, or 440V and any of these will work.
I just checked my little stash and the closest that I have is a ten.

You can get those things pretty cheap on Ebay and Amazon if you can wait or you can probably find one at a refrigeration supply house.

[Bucksaw]

I found one on Amazon for about $8. Got it all hooked up and now it runs again. It still takes a bump to get started, but it runs great after the push. It also runs super quiet now. Not sure if it's the new part or the fact that I cleaned about 5 lbs of dust out of it.

[simsknives]

The one that I run mine off of is a 1 1/2hp compressor motor. There may be a electric motor repair guy around you that has a bunch laying around. If you replace it I would definitely go 1 1/2- 2hp if you can.

[Bucksaw]

Well, this is one of those cheap, one piece belt sanders like you get from Harbor Freight, so I wont be replacing the motor, but I may replace the whole grinder with the 2x72. I am going to start with the 1/2 hp from red, if I can get any express run set up, and then after I get the grinder paid for I will look at replacing the motor. Until then, I will do what I can with what I have.