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abunaitoo
08-24-2015, 12:07 AM
I have a Craftsman disc/belt sander, 137.215360.
I think I need a new start capacitor.
After I use it for a few minutes, it won't start.
When it cools down it starts and runs fine.
The capacitor gets hot, and looks like it's leaking some kind of gray plastic goo.
Checked the Sears web site and the capacitor is no longer available.
Marking on it is:
LAI
25uf
250v.AC
The cross over number I get is OLZZ.
I can't find it anywhere.
Anyone know about these things????
147365

bangerjim
08-24-2015, 12:12 AM
Forget Sears!!!!!!!!!

The cap is on the motor. Just go to Grainger.com and see if they have one. Or a local motor supply shop. Any local shop that repairs motors will have one.

25uf @ 250vac is not uncommon for a starting cap.

I have one of those same sanders in the shop.

banger

EOD3
08-24-2015, 12:33 AM
On the off chance you don't know what the "uf" stands for it's Micro Farad (normally pronounced "micro puff").

Replacing it shouldn't be a big problem but ***WARNING*** installing it backwards will cause the capacitor to explode the first time the power hits it. I don't mean "let the smoke out", I mean explode.

abunaitoo
08-24-2015, 03:46 AM
I'll check with an electrical shop.
We have a granger here. When the opened, I went there to look around.
Found a plier I was looking for. Went to pay for it and was told they only sell to accounts.
Did I want to set up an account. NO.
I sent an email to complain.
They replied that they do sell to walk in's.
I sent them the date, time, description of the salesman, what I wanted to buy.
They replied that no one there would do that.
Never went back again. Will never have anything to do with them.

Didn't know you could install it backwards.
I don't see any markings on it.
Both wires are the same color. Red.
How would I know if it's backwards????

garym1a2
08-24-2015, 06:11 AM
Being an A.C capacitor you have no backwords.

pmer
08-24-2015, 07:50 AM
You could try searching the net for a capacitor. Ebay and Amazon probably have them.

Gar
08-24-2015, 09:05 AM
http://www.zoro.com/dayton-motor-start-capacitor-25-30-mfd-round-6flu3/i/G1559004/

Petrol & Powder
08-24-2015, 09:09 AM
/\ There's your solution. Done.

tcbnick
08-24-2015, 09:19 AM
I've bought from Zoro before, and No Problems

akajun
08-24-2015, 09:35 AM
Mcmaster Carr, Grainger, Surplus Center, local motor shop, Ace Hardware, HVAC supply, many places to get them. You dont have to exactly match it either, You are looking for a 250volt ac capacitor with a minimum of 25uf. Many capicitors are sold in ranges, such as 25-50uf.
and you cant wire an ac capicitor in backwards. But remember, they do hold a slight charge. touching both ends to a voltage tester will often discharge them.

bangerjim
08-24-2015, 09:39 AM
On the off chance you don't know what the "uf" stands for it's Micro Farad (normally pronounced "micro puff").

Replacing it shouldn't be a big problem but ***WARNING*** installing it backwards will cause the capacitor to explode the first time the power hits it. I don't mean "let the smoke out", I mean explode.

There IS no "backwards" with AC caps!!!!!!! Only DC.

LuckyDog
08-24-2015, 05:06 PM
And then only with Electrolytics.

But Gar have you the solution.

rtlindsey22
08-24-2015, 09:33 PM
Or you could try a swimming pool supply company.

abunaitoo
08-24-2015, 10:38 PM
Living on an island has it's good and bad.
Good would be the weather.
Bad would be we don't have many replacement parts.
Vendors here would rather you buy a new one, and not fix the old one.
Spent almost all day calling around, and none on island.
I ordered one from Amazon.
Thanks for all the help.

Petrol & Powder
08-25-2015, 07:26 AM
I didn't even notice your location. I bet that does add to the cost of things.
Unless the shipping charge was huge you will still come out way ahead.

abunaitoo
08-25-2015, 07:16 PM
Someone on another forum said it could be a Run capacitor.
Is there a way to tell if it's a Run or Start capacitor????
Are they the same????
Motor has only this one.
No label or markings on the motor.

Petrol & Powder
08-25-2015, 07:38 PM
Not always the same but yes they are the same in your case.

Wiki isn't always correct but they got this one right:
https://en.wikipedia.org/wiki/Motor_capacitor

6bg6ga
08-26-2015, 07:21 AM
147504


I'm a little late getting to this thread. Is your capacitor two wire or three wire? This will tell you quickly if its a start /run because a start run will have a common, a small capacitance for the start cycle and a larger capacitance for the run cycle. Thus three wires or three terminals. If you just dealing with a single capacitance in the start cycle its not uncommon and not unforgivable to up it slightly and this gives an extra little kick in starting up. This is a common practice hence the term hard start in refrigerators/freezers/ air conditioning and blower motors.

If your still having difficulty obtaining a start cap I will gladly send you the one pictured free of charge. It is rated at 5mfd fan and 35 mfd. It would work in place of your 25mfd cap. It had a 5 mfd for a fan. Its rating is 5 mfd, and 35 mfd and 370 volts AC.

Jeffrey
08-29-2015, 10:57 AM
DON'T replace a 25uf capacitor with a 35uf. You will burn out the start winding. If the exact uf rating cannot be obtained, you have to stay within 10% of the original. If you need a 25uf and cannot get one you can parallel wire two capacitors together that add up to 25 to get out of a bind. Also you can go higher on the voltage rating on a cap, just not lower. The voltage rating is a measure of how good the insulation is inside the cap. Dual caps are typically for use in a air conditioner condenser. The lower rating is for the condenser fan, the larger is for the compressor.

6bg6ga
08-29-2015, 03:38 PM
DON'T replace a 25uf capacitor with a 35uf. You will burn out the start winding. If the exact uf rating cannot be obtained, you have to stay within 10% of the original. If you need a 25uf and cannot get one you can parallel wire two capacitors together that add up to 25 to get out of a bind. Also you can go higher on the voltage rating on a cap, just not lower. The voltage rating is a measure of how good the insulation is inside the cap. Dual caps are typically for use in a air conditioner condenser. The lower rating is for the condenser fan, the larger is for the compressor.No You Won't been there

Jeffrey
08-29-2015, 06:31 PM
I've dealt with this supplier here in south LA. Give them a try for your capacitor. Johnstone Supply, 1320 Kalani Street, Honolulu, HI 96817

abunaitoo
08-30-2015, 06:28 AM
Thanks for all the help.
I'm almost sure it's a start cap.
When it got hot, the motor wouldn't start. It would just hum.
Once it cooled down, motor would work.

I got the cap today.
25-30uf, 250vAC.
Tomorrow range day.
Will try to install it on Monday.

I checked with Johnstone here. They didn't have one that small.

A side note on the motor. It has no cooling holes. Both side plates are solid. Strange.
I've had the sander for over 10 years. First problem I've ever had with it.

jsizemore
08-30-2015, 09:13 AM
I bet the lack of cooling holes is to cut down on dust in the motor. In the good old days of foam blank shaping you could go through many sanders. Folks converted over to air tools and the problem went away.

6bg6ga
08-30-2015, 09:16 AM
Thanks for all the help.I'm almost sure it's a start cap.When it got hot, the motor wouldn't start. It would just hum. Once it cooled down, motor would work. I got the cap today. 25-30uf, 250vAC.Tomorrow range day.Will try to install it on Monday.I checked with Johnstone here. They didn't have one that small.A side note on the motor. It has no cooling holes. Both side plates are solid. Strange.I've had the sander for over 10 years. First problem I've ever had with it.Contrary to what some may think you can use a higher value start cap if you have to. It WILL NOT burn up the start windings but will cause a problem if used in the run position. I worked on refrigerators, freezers, and air conditioning for many years in addition to working maintenance in various factory environments as well as working for motor repair facility. It was commom practice to use what is referred to as a hard start cap in conjunction with the start cap or to up the size of the start cap in order to eliminate a starting problem that is sometimes associated with power going under the typical 120volts. In addition I have also used a larger value in regular motors if I didn't have the so called "perfect cap". Generally, it is a common practice to NOT deviate over 10% of the caps value. This however brings in another amusing point and that is the value of many caps can be plus or minus 20% of the posted value. If on wants to be perfect you will get out your capacitor checker and run a test on the actual value of the said cap. If you cannot find the perfect cap you have several options... Smaller caps in parallel will yeald the value. Larger caps in series will yeald the proper value. Unequal caps in series is also a way to obtain the correct value and there is a formula for this if you want that option. Sound like you have the situation covered now.

abunaitoo
08-31-2015, 05:35 PM
Installed the cap. Put the sander back together. Ran it for about 10m.
Everything is good. Cap didn't get hot at all.
Sander is happy again.
Thanks y'all.

bangerjim
08-31-2015, 05:50 PM
Your motor is sealed to prevent sanding dust and grit from getting inside. Mine is the same way.

Plan on replacing starting caps ever 20 years or so! I do. When the motor hums and will not start, it is most always the cap. I can drive over to Grainger (3-4 miles in any direction from here!) and get what I need.

Glad you got it fixed. That sander is built well, as it is 20-35 years old. Mine runs great. Has made a lot of antique clock and instrument reproductions over the years.