Electric Motor Start Capacitor

[D45]

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

Wired and will be used with a standard wall outlet

The motor is marked Capacitor Start Motor

There's two wires and the dirt outline on the case, indicating to me the Capacitor is missing?

Can someone please let me know what I need?

 

[D45]

I guess I'm just looking for suggestions on what type/size to try

I've seen a wide variety online

285 MFD Capacitor(238 MFD, 125V Start Capacitor & 20 MFD, 240V Run Capacitor)

Start Capacitor 233 to 259

125V Start Capacitor, 20 MFD, 240V Run Capacitor), 285 MFD Capacitor(238 MFD)

Alot of options........

I saw one 1/3hp unit had a 519 MFD Capacitor

 

[Cruzan80]

So all of the ones you listed are between 230-285, which IIRC seems about right for a 1/3HP motor. When I put in the model no, first link was for Grainger. Have you tried giving them a call?

 

[micromind]

That motor doesn't have a run capacitor, just a start one.

I've seen these from about 100 MFD to 650 MFD. Generally speaking, smaller motors use smaller capacitors but not always true.

You'll also need a cover for it, Grainger could very likely get one for you. They're a pretty standard size.

 

[D45]

Correct I just need to find a start capacitor

 

[FrankLee]

Do you know if the motor even works?

 

[D45]

Yes it does. The PO said it didnt......

He was using a 3 wire plug that was missing the round ground at the plug end and the green ground on the motor was not even crimped on the ring terminal

I temporarily fixed both and the motor would turn over and run, when I manually started the motor by slightly spinning the shaft ......leading me to believe it needs the start capacitor

Once running and spinning it sounded quiet and smooth

 

[nadogail]

One phone call to Grainger with the Dayton Model Number from the motor information lable should get you a capacitor shipped to your door.

 

[D45]

Thanks I'll call them up and let you guys know

 

[larry4406]

Turns out I have 2 different Dayton Capacitor start motors but mine are higher horse power compared to yours so I am not sure if this is helpful.

First Motor is a 6K759A 3/4 HP 1725 RPM 115/230V 11.6/5.8A. It has a 485-540 MFD capacitor by Philips. Note the side dimples in the capacitor cover; these create a slight interference with the the capacitor and holds it snug inside.


Second Motor is a 6K2468 1 HP 1725 RPM 115/230V 14.8/7.4A. It has a 540-648 MFD capacitor by Philips.


Here is a picture of what your capacitor holder should look like. The rounded end goes down which provides extra room for the leads.

 

[FrankLee]

If you get the specs from Grainger, AirStar Supply has decent pricing on caps; US-made and free shipping.

EDIT: 12/12/23 @ 11:37

Airstar Supply | Solutions for Today's HVAC Problems

www.airstarsupply.com

 

[American Locomotive]

Something to keep in mind is that the starting switch or start winding may be bad, hence why someone removed the capacitor to investigate.

 

[D45]

Ok thanks. I'll start with the capacitor first since it should be relatively inexpensive to try.......$20 is cheaper than a $300 motor and having a shop $175 to rebuild it

 

[D45]

If and when the capacitor doesn't work, I'll figure out options for a replacement motor

I am not even going to waste money right now on a cover for the capacitor, until I know the capacitor works

 

[D45]

First Motor is a 6K759A 3/4 HP 1725 RPM 115/230V 11.6/5.8A. It has a 485-540 MFD capacitor

Second Motor is a 6K2468 1 HP 1725 RPM 115/230V 14.8/7.4A. It has a 540-648 MFD capacitor

Interesting!

I have a 1/3 HP 1725 RPM 115/230V 6.8A/3.4A

Wildly guessing I'll use a 233 to 280MFD

 

[larry4406]

First Motor is a 6K759A 3/4 HP 1725 RPM 115/230V 11.6/5.8A. It has a 485-540 MFD capacitor

Second Motor is a 6K2468 1 HP 1725 RPM 115/230V 14.8/7.4A. It has a 540-648 MFD capacitor

Interesting!

I have a 1/3 HP 1725 RPM 115/230V 6.8A/3.4A

Wildly guessing I'll use a 233 to 280MFD

I have no idea on how to scale the capacitor rating. Is it linear with amperage?

 

[D45]

216-259 MFD is what I found online

See what Grainger says

 

[BrandonV]

Probably somewhere around 200 MFD.

Baldors with the same specifications tend to specify a 189-227 MFD.

 

[D45]

Well......things might change

I was told that a drip proof motor, that is currently installed, should never be mounted vertically.

I need a 1725 rpm 115v motor with 56c mount and a 5/8 keyed shaft

 

[D45]

Should I look for a 1/3hp or upgrade to a 1/2hp

 

[D45]

If the motor isnt in constant operation and its just used to raise and lower the platform, there's no concern for liquids falling into the open hot motor case

 

[D45]

I'm going to get a capacitor and run it

I'll fabricate a cover if it becomes and issue

 

[D45]

Grainger stated:
161-193 MFD
2MDR4

They did not have a part number for the capacitor cover though.......

 

[larry4406]

Grainger stated:
161-193 MFD
2MDR4

They did not have a part number for the capacitor cover though.......

Small Red Bull can and some snips for the cover? Double sided tape or Velcro tape to hold the capacitor inside the can?

 

[D45]

Exactly what I'm planning

Capacitor ordered for $12 shipped

 

[larry4406]

Exactly what I'm planning

Capacitor ordered for $12 shipped

Be mindful of making sure the leads don’t short out on the can/cover.

 

[American Locomotive]

Well......things might change

I was told that a drip proof motor, that is currently installed, should never be mounted vertically.

I need a 1725 rpm 115v motor with 56c mount and a 5/8 keyed shaft

Drip proof just means the motor does not have vents on the top of the motor housing, and any front/rear vents are angled down so water falling can't easily enter the motor. An open drip proof motor mounted vertically is no longer drip proof, as water will just fall right in the vents.

The motor itself don't care which way it's mounted.

 

[D45]

I'm thinking an old soup can since it's thicker for the capacitor cover

 

[D45]

Next question.....how do I know what wire goes to what terminal on the capacitor?

 

[mike93lx]

Posting every question 2x makes something hard to follow. I'd ask a mod to combine your threads

 

[FrankLee]

Next question.....how do I know what wire goes to what terminal on the capacitor?

It doesn’t matter, except that some start caps have multiple spade connectors from each leg. That should be obvious tho not to use the same leg.

 

[RPH]

Some caps are designed to be a combo capacitor. It has both start and run windings attached. Make sure you’re using the start cap side of it. Higher voltage and higher capacity of the markings usually won’t cause any problem.

 

[micromind]

It doesn’t matter which wire goes to which terminal.

 

[D45]

Overall Height 2-3/4 in

Overall Width 1-7/16 in

 

[D45]

Capacitor installed and the motor fires up on its own

Seems to be running fine

 

[D45]

Need to fab up a cover now

 

[Max]

Need to fab up a cover now

It’s great that it works. If it was me, I’d add a rubber grommet in the hole to protect the wires from wear due to vibration. Or at least some heat shrink if you don’t have a grommet.

 

[D45]

Good idea. I have a rubber grommet kit assortment

 

[dogdog]

Need to fab up a cover now

You probably over spec on the voltage. Bigger capacitance bigger the size
Bigger the voltage spec on the capacitor bigger the size

 

[D45]

Huh? The capacitor mfd is the manufacturer specs per grainger