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+-- Thread: Changing motor capacitor (/showthread.php?tid=7330568)
Changing motor capacitor - stav - 05-29-2017
I attempted to start my Belsaw planer a few weeks ago. It started slow and never seemed to get to speed. Then there was a bit of oil that ran out of the box on the side of the single phase 3 hp motor. I checked and it was from the capacitor inside the box. I got a replacement and was looking at wiring it in but I can't determine which wire goes to which pole. There are no indicators on the capacitor indicating any kind of polarity. I looked it up and some say it does matter and some say it doesn't. I checked the capacitance and it seemed to be different depending on which way you connected the tester. Based on what research I have done, it appears to be a run capacitor. Anyway, I don't want to connect it incorrectly and cause damage to the motor or the new capacitor. Any ideas or guidance would be greatly appreciated.
RE: Changing motor capacitor - Roly - 05-29-2017
If the capacitor just has two connections on it (single value ) it does not matter. They would be marked iif it mattered. A three connector type ( dual value) will be marked Roly
RE: Changing motor capacitor - daddo - 05-29-2017
Just two wires and two poles- it doesn't matter.
RE: Changing motor capacitor - stav - 05-30-2017
Thanks for the confirmation. Wired it in and it is humming but not turning. Looks like I need to take a look at the centrifugal switch next.
RE: Changing motor capacitor - Phil Thien - 05-30-2017
(05-30-2017, 07:19 AM)stav Wrote: Thanks for the confirmation. Wired it in and it is humming but not turning. Looks like I need to take a look at the centrifugal switch next.
Are you sure there isn't a second capacitor? Maybe you replaced the run but not the start cap?
RE: Changing motor capacitor - stav - 05-30-2017
Unless it is hidden inside the motor somewhere, this is the only one that is visible.
This the motor box and that is the capacitor I changed. There are no other humps on the motor.
![[Image: 20170409_142327_zpsida5giw0.jpg]](http://i271.photobucket.com/albums/jj138/rdfish/20170409_142327_zpsida5giw0.jpg)
RE: Changing motor capacitor - TDKPE - 05-30-2017
Looks like a vented motor. Make sure the centrifugal switch is closing, or the start winding won't be in the circuit. Could be dust in it, or corrosion, or just plain sticky.
If you give it a spin by hand, then hit the power switch (no belts, and hands away when putting power to it), will it start and run normally?
RE: Changing motor capacitor - stav - 05-30-2017
when I was messing with it last night, the shaft was spinning freely. I spent about 20 mins blowing it out, but the vent holes are all around the bottom of the frame and are not the easiest to get all the way around the housing.
I have not tried spinning it after I turned it on. I was shutting it off right away so I didn't do any additional damage if there was a problem.
RE: Changing motor capacitor - TDKPE - 05-30-2017
(05-30-2017, 01:01 PM)stav Wrote: I have not tried spinning it after I turned it on. I was shutting it off right away so I didn't do any additional damage if there was a problem.
Spin it before you turn it on, after your hand is out of the way. Use a rope, like an old-school small engine. Just be sure the rope is off before you hit the power.
If it's the start circuit (second winding, with capacitor), it will run in either direction, regardless of how it's wired - the direction comes from the start winding.
RE: Changing motor capacitor - stav - 05-30-2017
I can do that. I will try it if I get home from work early enough tonight.