Electricians I need a little advise

[dchristal]

Do you know if the power on the blue wire with the motor is off is normal? Is it there to charge up the capacitor? Thanks Chris.

Looking at your schematic, it doesn't appear that any power should be transmitted to the motor except under power. However, some 220v 1ph motors (used on lathes) do have power when switched off, such as seen on page 62 of this one: http://metalworking.com/DropBox/_2001_retired_files/sbarmylathe.pdf

You may not want to assume that this is a problem. You should be able to follow the blue wire to KM3 to see if the contacts are welded shut. Of course, I'd get my hands on a replacement for a known blown 150uf cap before I got too deep in looking everywhere else, but I've said that 3 times so I'll just stay out of it for a while. I'd also be checking the centrifugal start capacitor disconnect that Dick mentioned in the mean time.

 

[Chris Byrne]

Ok I got a replacement cap today and left the motor at the motor shop to have them check the switch assy. They will check and replace the switch for $15 so I might as well have it done now while the motor is out. Once back I will install it and see it it runs and sounds correct before I do anything else. Thanks everyone. Chris.

 

[Chris Byrne]

I got the call today. Motor shop says there are two switches in the motor and they are fried, and the windings look "old" I asked if the insulation was burned or blown apart or if it just looked old. I mentioned I had checked for continuity to ground(case) and there was none. He said well the switches are bad and he cant find replacements so a new motor is $780 plus tax. I will pick it up tomorow and take it apart myself. if I cant do something with it, it is junk already. I have a feeling I can get it going though. If not I called today and an oem motor is $320 I know they are likely quoting me a baldor motor or something similar but for 10 years of hard service $320 is fine with me.

 

[rhncue]

I got the call today. Motor shop says there are two switches in the motor and they are fried, and the windings look "old" I asked if the insulation was burned or blown apart or if it just looked old. I mentioned I had checked for continuity to ground(case) and there was none. He said well the switches are bad and he cant find replacements so a new motor is $780 plus tax. I will pick it up tomorow and take it apart myself. if I cant do something with it, it is junk already. I have a feeling I can get it going though. If not I called today and an oem motor is $320 I know they are likely quoting me a baldor motor or something similar but for 10 years of hard service $320 is fine with me.

What make lathe is it? Years ago I had the same problem with that centrifugal switch burning up on an Enco lathe and being a Chinese motor I couldn't get parts. I just by-passed it. I went to Auto-Zone or some such place and bought a heavy duty push button momentary switch used for a starter or horn or such on a vehicle. I mounted the push button on my lathe where it was easy to access and then extended the two wires running to the old switch and put them onto the new switch. Then, when I wanted to start the lathe I would hold this button in when I turned on the lathe with the normal switch. Once the motor was up to speed I would release the button which then would cut the voltage going to the start capacitor and all was fine. I used it this way until I got a hold of an old motor that had a good switch in it and I adapted that one. I am still using this set-up on my shaft machine.



Dick

 

[Mc2]

I don't care for motor rebuilders as they tend to do repairs weather needed or not. But if it is bad it may smell.

Good luck.
Jim.

Chris when you check the windings to ground you will want to use what is called a Megger. This is simular to a multi meter except it puts up to 1,000 volts through the coils and checks to ground not 9 volts. Oil, dirt and moisture will conduct. Now the coils will show shorted to each other, that is normal. If you want to know if the coils brock down and shorted to each other than a milli ohm meter is needed. This is rare. However then each coil should re less than .5 ohms and within 10% of each other. That is not alot of difference. I have seen too many motor shops do extra work since they can't make any money on a $15 switch. If it is an import you should be able to get switch from grizzley or alike. The imports will use alot of the same parts. A $15 camble is pretty cheap.

good luck, Jim.

 

[d_flash]

Chris, have you called the Harbor Freight help line ? sometimes they have replacement pieces for their stuff. 1.800.444.3353

I noticed the part numbers on your posts were Harbor Freight items.

>

d_flash

 

[Tooljunkie]

Chris , It seems like I was quoted around $450 for an American made replacement motor when I had a problem with mine. Find the frame # on the name plate and search on ebay and google and you will probable find a good deal. good luck , Jim

 

[Chris Byrne]

I picked up the motor today and I feel like I have been to an auto mechanic! LOL (My profession) I asked the guy what was up with the windings and he says I don't know the other guy took the motor apart. We look at it and he says the windings look fine. I tell him the guy on the phone said they look old. He looks puzzled for a moment then said "OH OH yeah, He ment they look like old style windings" I could tell he was reaching on that one. I said ok, can you show me what the "new style" windings look like. LOL He got a funny look and said I don't have any apart at the moment.
I asked if I could return the cap I bought for it as the motor is "no good" and the guy said no. I explained that they still had it and it had not left the building. No returns on electrical parts!!! He says. Ok, I think the motor is salvagable so I will need it anyway if it is. I pay the $15 and I am out the door.
I take the box of parts to the shop and start to reassemble everything. I used a points file to dress the internal switch contacts and barely touched them and they were clean as a whistle. I tweaked the cintrifigual switch assembly (opens the cap switch contacts) so it was back to normal. One corner of a tab on it was slightly bent. I get the motor reassembled and add some extended wires as the new cap was too large to fit in the place of the older one. I pull my new cap out of the box to find it had been droped and the case cracked and chipped away. No wonder they don't accept returns that have not left the building. I will install it tonight to see if it works now. will be calling the owner of the shop monday about the cap breakage.
I understand them not wanting to dress contacts as they are a shop with a warrenty but as for the rest I think they totally lied on the windings and they broke the cap. I guess I will see what he has to say.

 

[Mc2]

I picked up the motor today and I feel like I have been to an auto mechanic! LOL (My profession) I asked the guy what was up with the windings and he says I don't know the other guy took the motor apart. We look at it and he says the windings look fine. I tell him the guy on the phone said they look old. He looks puzzled for a moment then said "OH OH yeah, He ment they look like old style windings" I could tell he was reaching on that one. I said ok, can you show me what the "new style" windings look like. LOL He got a funny look and said I don't have any apart at the moment.
I asked if I could return the cap I bought for it as the motor is "no good" and the guy said no. I explained that they still had it and it had not left the building. No returns on electrical parts!!! He says. Ok, I think the motor is salvagable so I will need it anyway if it is. I pay the $15 and I am out the door.
I take the box of parts to the shop and start to reassemble everything. I used a points file to dress the internal switch contacts and barely touched them and they were clean as a whistle. I tweaked the cintrifigual switch assembly (opens the cap switch contacts) so it was back to normal. One corner of a tab on it was slightly bent. I get the motor reassembled and add some extended wires as the new cap was too large to fit in the place of the older one. I pull my new cap out of the box to find it had been droped and the case cracked and chipped away. No wonder they don't accept returns that have not left the building. I will install it tonight to see if it works now. will be calling the owner of the shop monday about the cap breakage.
I understand them not wanting to dress contacts as they are a shop with a warrenty but as for the rest I think they totally lied on the windings and they broke the cap. I guess I will see what he has to say.

Sorry Chris, didn't feel like quoting myself again. I have never cared for motor re-build shops nor auto repairmen for that matter. Now, had the motor gone back to the original MTB, not cost effective, then I would excepted their analogy.

Keep an eye out for that burnt and or stuck contact.


Jim.

 

[Chris Byrne]

Sorry Chris, didn't feel like quoting myself again. I have never cared for motor re-build shops nor auto repairmen for that matter.

Jim.

Jim. I talked with the counter guy and felt he was trustworthy. Whoever called my on the other hand I believe was a thief. I have never dealt with rebuilder shops before so, now I know.
I got the motor back in and working but I do want to replace the Mechanical switch and elec contacts. I will contact harbor freight and ask if it is possible to order the parts. If not I will price a new motor locally. I can order an original one for $320.
Funny thing is when I bought this lathe years ago I expected to only use it for a year or two then upgrade to an american lathe when I found one. I kept saying when this thing breaks I will have an excuse to go out and find a better one. Well all these years later and this is the first issue I have had. It is still as accurate as the day I first set it up. I inherited my friends lathe and mill when he passed. They are identical to mine so all the tooling interchanges. After all these years I must say I am suprised at how well these have worked out. I think I may have been lucky to get ahold of machines that actually hold tolerance from H.F. but, they have worked fantastic and for the money have been a great deal. Chris

 

[Chris Byrne]

Thanks everyone for all the help and calls and pm's. I am just glad to have it back up and running.
I took the oportunity to raise the lathe since I had the hoist out. I raised it 6 inches first and that made it a little too high so tomorow I will drop it down 3 inches. It was just a little low when I use floor mats and I found I was always bending over slightly when working. I ballparked the 6 inches and although I liked the height it was just a bit too tall. Chris.

 

[Chris Byrne]

Oh yeah I snapped a couple pics of the "old looking windings". The bottom spring is broken and out of place on the bottom picture. I put it back together but dont expect it to last.

 

[dchristal]

I got the motor back in and working but I do want to replace the Mechanical switch and elec contacts.

Do you have a final analysis? Centrifugal start switch stuck and subsequently fried the start cap? Run cap died? Motor stalled & start cap re-engaged?

Just curious.

Harbor Freight is my home away from home.

 

[Chris Byrne]

The motor has a 20uf and a 150uf cap. The 150 is the one that exploded. My guess is the spring that broke allowed it to stay on too long causing damage. All I know about capacitors is that they store power and can discharge it rapidly. Also they can offset a phase of power on ac voltage. I do not know how much is too much as far as power being applied to them.
The centrifugal switch is damaged, the start cap switch contacts were a little burned but really not very bad, they cleaned up very easily. and last the cap. I think if I can find a new switch assy It will be fine for a while. If not I will order a new motor and have it on hand for when it is needed. Chris.