Electric Motor Start Capacitor

[dogdog]

Huh? The capacitor mfd is the manufacturer specs per grainger

if you buy a 240V vs buying a 450V rating cap of the same MFD the 450V would be larger by a lot...

 

[D45]

Specs didn't call for either of those

110v-125v

 

[micromind]

it's perfectly fine to use a higher voltage capacitor but not lower.

The voltage stamped on a capacitor is the maximum it can handle so higher is ok.

And yes, a higher voltage capacitor will usually be larger.

 

[The Cobbler]

to OP, I have a few motor cap covers . might have something you're looking for . is this the size of the cap I assume?

Overall Height 2-3/4 in

Overall Width 1-7/16 in

 

[D45]

Awesome yes that's the capacitor size

Looks like the cover needs to have top and bottom mounts, not on the sides

 

[The Cobbler]

I'll look in my stash and see what I have .

 

[D45]

Grommet installed

 

[D45]

Here's the cover area

 

[RPH]

Higher voltage capacitors are physically larger due to the increase in the insulation between the poles. Higher voltage will jump the gap between the plates. Once started it’s usually over microseconds later in a bang. Polarized caps are even more fun with the bang and confetti falling.

 

[exmaxima1]

I wouldn't bother with fabricating a cover until I tested the motor with the new capacitor. As noted earlier, there might be an issue with the start winding or the centrifugal switch since the original cap and cover are missing.

 

[D45]

Capacitor installed and the motor fires up on its own

Seems to be running fine

See post #35

 

[micromind]

Quite often the cover will get smashed off and in doing so, the capacitor will get wrecked. The rest of the motor is fine.

 

[nadogail]

AC ( Alternating Current) capacitors are not Polarity Sensitive. Either way you hook it up will be fine.

DC ( Direct Current) Capacitors are often Polarity Sensitive.

 

[dogdog]

Specs didn't call for either of those

110v-125v

I have a Dayton 1/3hp motor 115v/230v

Not sure what spec you were looking at.

 

[Cruzan80]

Yes, the start winding is usually set up to only see one leg, regardless of 115 or 230v. So this way, it works in both configurations.

 

[The Cobbler]

here's what I have
both are just shy of 2" wide ( inside measure) x4 " & 5" .
the mounting tabs are on the sides . both have semi good seals . moving the tabs would be an easy job , but if you were careful you could probably re drill the motor case. cover shipping & 1 is yours . but, not sure about shipping to US from Canada , it's probably at least $25 by Canada Post ,

 

[D45]

Thanks for all that

For now, I am going to try to find a capacitor cover to fit the preexisting holes in the motor case

 

[bronc076]

I like the soup can idea above. I had a bunch of vintage steel beer cans I gave to the local barber shop as they use them for decoration. I would have sent you a couple for free just to see the final product!

 

[D45]

I took a capacitor cover off my Craftsman drill press, it was a close fit......but I also can't find the part number for that haha

 

[larry4406]

How about a short piece of pvc pipe say 2” diameter?

Wafer cap glued on one end, other end push on cap (no glue).

Drill thru sides to align with your motor’s threaded holes. Use different size holes. Hole closest to motor just clears the bolt thread while hole opposite is larger diameter for nut driver/screw driver/hex key to clear. Use washers as standoffs between pvc and motor to provide clearance for hub of push on cap.

 

[D45]

I really want to find a used cover that fits

Has to be many similar motors with very similar specs and mounting hole pattern

Like I said the cover on my craftsman drill press was very close. I could make that work, if I knew the cover part number! Haha

 

[D45]

Used cover located for $20

Hope it fits

 

[D45]

Does the capacitor just sit inside the cover or should anything be used to help with vibration and insulation

The cover arrived and fit well

I'll get some pics of soon

 

[mike93lx]

Does the capacitor just sit inside the cover or should anything be used to help with vibration and insulation

The cover arrived and fit well

I'll get some pics of soon

I'd put in a piece of foam if for no better reason than rattles drive me nuts

 

[nadogail]

Toothpicks or Popsicle sticks can sometimes work as “gap fillers”.

 

[larry4406]

Does the capacitor just sit inside the cover or should anything be used to help with vibration and insulation

The cover arrived and fit well

I'll get some pics of soon

I'd put in a piece of foam if for no better reason than rattles drive me nuts

On the Dayton’s I posted pictures of, there was an indent on the side of the cover which created a snap force fit with the capacitor. It holds it snug.

What is odd is that mine have the leads at the bottom so gravity works against it. At some point in time the leads could probably ground out if the capacitor slipped making things unhappy.

 

[D45]

I will pack it with something to prevent movement and vibration and also wrap the capacitor connections with electrical tap

 

[D45]

Snapped firmly into the cover

 

[The Cobbler]

Snapped firmly into the cover

good to go. glad it all worked out for you

 

[D45]

Does the motor have to be grounded to the lift frame?

Or is running the power cord ground to the motor sufficient?

 

[micromind]

The motor needs to be grounded at the motor frame no matter what.

If it has a rigid base, the machine can be considered grounded by the mounting bolts. If it has a resilient cradle base, (rubber mounts), you'll need a jumper from the motor frame to the base. The factory has installed these for many years.

 

[D45]

The motor will be bolted directly to the metal frame, no rubber isolation