Motor quits

Forum for Maintenance and Repair topics. Feel free to ask questions or contribute.

Moderators: HopefulSSer, admin

Ron309753
Gold Member
Posts: 355
Joined: Tue Jul 01, 2008 10:25 pm
Location: Marengo, OH

Motor quits

Post by Ron309753 »

I inherited a Shopsmith (SN: 309753) from my Father-in-Law. It had been sitting my garage for 18 months when I decided to clean the garage. I knew it wasn't working so I decided to check it out to see if I could get it to go. The problem turned out to be the power switch. I got a new one at the Home Depot, but they only had one in stock and the packaging had beem stapled back together. I hate it when they do that. I also had to repair the speed control. I have everthing back together now, but I am having a problem. The motor will quit at any speed and not want to turn back on. I have to flick the switch numerous times to get it go. I checked the motor and it wan't hot, and when I tried it this morning with a cold motor it did the same thing. Since the quill and auxillary spindles turn freely, and nothing seems to be binding up, I am thinking that I have an electrical problem, not a mechanical one. I also noticed that when I had it plugged in to power strip, it would trip the power strip circuit breaker every time I turned it on. I was wondering if there is some kind of transformer or something on the motor that is faulty, or if I have a bad switch (someone's reject), or if the motor is pulling too many amps.


Sincerely,

Ron
User avatar
billmayo
Platinum Member
Posts: 2342
Joined: Fri Jul 21, 2006 3:31 pm
Location: Plant City, FL

Motor quits

Post by billmayo »

Power strips have a 15 Amp circuit breaker. The 1 1/8 HP motor requires 18-20 Amps when first starting. If an extension cord is used, it must be 12 ga and no longer than 25 ft. An longer needs heavier cable. You really need a dedicated 20 Amp circuit for the Shopsmith. When quiting for the day, you can move the speed control to SLOW to reduce the starting load for the next days use.

When you flip the switch, does the motor hum. If not, then you have a switch or power problem. I find I have to use 20 AMP or higher rated switch for the Shopsmith. The 15 Amp rated switch can fail over time.

If the motor hums but not starting, then it is the start winding relay contact points or the capacitor that needs to be checked. You will need to remove the motor from the Shopsmith to do those checks.
Ron309753 wrote:I inherited a Shopsmith (SN: 309753) from my Father-in-Law. It had been sitting my garage for 18 months when I decided to clean the garage. I knew it wasn't working so I decided to check it out to see if I could get it to go. The problem turned out to be the power switch. I got a new one at the Home Depot, but they only had one in stock and the packaging had beem stapled back together. I hate it when they do that. I also had to repair the speed control. I have everthing back together now, but I am having a problem. The motor will quit at any speed and not want to turn back on. I have to flick the switch numerous times to get it go. I checked the motor and it wan't hot, and when I tried it this morning with a cold motor it did the same thing. Since the quill and auxillary spindles turn freely, and nothing seems to be binding up, I am thinking that I have an electrical problem, not a mechanical one. I also noticed that when I had it plugged in to power strip, it would trip the power strip circuit breaker every time I turned it on. I was wondering if there is some kind of transformer or something on the motor that is faulty, or if I have a bad switch (someone's reject), or if the motor is pulling too many amps.


Sincerely,

Ron
Bill Mayo bill.mayo@verizon.net
Shopsmith owner since 73. Sell, repair and rebuild Shopsmith, Total Shop & Wood Master headstocks, SPTs, attachments, accessories and parts. US Navy 1955-1975 (FTCS/E-8)
User avatar
wa2crk
Platinum Member
Posts: 3080
Joined: Sat Jul 22, 2006 7:37 am
Location: Leesburg, Fl

Post by wa2crk »

Hi;
I am thinking that you maight have a bad switch again.
Try to get a good quality switch from an electrical supply house or from Grangers. The switch contacts should be rated for a twenty amp circuit.
Also the power strip switch breaker is probably only rated for 15 amps and this is not suitable for the SS. In addition to all of the above circuit breakers can deteriorate over time because the bi-metal spring can become weak. The SS circuit should be minimum twenty amps and if you use an extension cord it should only be 12 gauge wire and not more than twenty five feet long.
The other things that that come to mind is an internal connection in the motor that when it gets warm the connection can open up and close again when the motor winding cools down. This is a rare occurence. The fact that the motor starts when you repeatedly flip the switch is indicative of a defective switch or a loose terminal connection at the switch. Your "new" switch contacts may have been damaged if they were not rated for the current demands of the SS motor. Excessive current through the switch will overheat the contacts and they can deteriorate rather quickly.
Good luck and kep us posted.
Bill
User avatar
wa2crk
Platinum Member
Posts: 3080
Joined: Sat Jul 22, 2006 7:37 am
Location: Leesburg, Fl

Post by wa2crk »

Hi Ron;
I re-read your post and have a question. Does the breaker trip everytime you turn the switch on?
If it does then I suspect a short circuit somewhere in the wiring. Flipping the switch several can have the effect of moving something just enough to clear the short temporarily.
When the motor quits does the breaker trip at the same time? Check all the wiring connections and the wire itself for any abrasions that may have exposed the inner conductor of the wire.
I onnce had a switch go bad on a bettery charger that actually fell apart when I touched the terminals, a condition caused by the switch being underrated for the application. Some engineers in manufacturing will spec parts that are just barely rated for the load to reduce costs going above the specs on a replacement is a good thing.
Bill V
User avatar
dusty
Platinum Member
Posts: 21359
Joined: Wed Nov 22, 2006 6:52 am
Location: Tucson (Wildcat Country), Arizona

Motor quits

Post by dusty »

Ron;

I too have reread your post and I have 2 cents worth to contribute.

While I do not specifically disagree with any previous recommendations I want to comment.

You have never said that you trip a breaker except after you plugged into a terminal strip. In my humble opinion, terminal strips have no place in my shop except on the work bench where I plug in things such as the battery chargers, drills, bench lights and such. Small appliances, in other words.

The Shopsmith should be plugged into a dedicated circuit; that is, nothing on it except the Shopsmith. That circuit must be rated at no less than 15 amps and should probably be 20 amps as has been recommended. The Shopsmith motor temporarily draws at least 13 amps when it starts.

However, your Shopsmith should start up and run with no load on a 15 amp breaker.

I believe you have properly eliminated the speed control and quill as likely candidates for causing this problem.

Your comments that catch my attention are:

"The motor will quit at any speed and not want to turn back on. I have to flick the switch numerous times to get it to go".

This comment would lead me on a search for why the power to the Shopsmith is intermittent.

It does not cause me to suspect an over current condition. If the motor started and then popped a breaker I would suspect too much current.

"I checked the motor and it wasn't hot, and I tried it this morning with a cold motor and it did the same thing".

I interpret that to mean - it turned on and then for no apparent reason stopped.

I don't read where you have said that the motor ever ran long enough to get hot.

I suspect that you have an intermittent loss of power caused by an intermittent open circuit either to the Shopsmith -or- in the Shopsmith.

First candidate is the switch and power cord.

Second candiate is the electrical connections to the switch.

Third candidate is the motor itself.

Anyone who owns a multimeter and knows how to use it can isolate your problem very quickly.

There is a switch internal to the motor that could cause a vaguely similar set of circumstances but your description of the failure mode doesn't seem to me to fit the characteristics of a centrifical switch failure.

Please do report back your findings. This is a situation that any one of us could have to deal with. Your findings just might save several of us a lot of trouble.
"Making Sawdust Safely"
Dusty
Sent from my Dell XPS using Firefox.
Ron309753
Gold Member
Posts: 355
Joined: Tue Jul 01, 2008 10:25 pm
Location: Marengo, OH

Post by Ron309753 »

Thanks fellas for all the advice. When I put the Mark V back together I replaced the power cable because the original cable was severely dry rotted and cracked. I’m not even sure the new cable is rated for 20 Amps, so as soon as I have enough cash I’ll get a new power cord and switch. The only reason I had the power strip in the garage was for a radio and TV. I used it for the ShopSmith because it was handy. I moved the power cable to an outlet. It didn’t trip the circuit breaker in the electrical panel, but the shutting off problem continued. Hopefully the new cable and switch will solve the problem.
I actually have 20 Amp service to the garage. It’s not a dedicated circuit, but the only things I have on at the same time as the ShopSmith are two overhead lights.
I’ll keep you posted.
User avatar
dusty
Platinum Member
Posts: 21359
Joined: Wed Nov 22, 2006 6:52 am
Location: Tucson (Wildcat Country), Arizona

Motor quits

Post by dusty »

It is great, Ron, that you have 20 amp service in the garage. You indicate a concern that the new cord might not be rated at 20 amp. While it will be good for you to change it out, I don't believe the cord itself is your problem.

You describe a "dropping out" condition without popping the breaker. That doesn't sound like anything that would be caused by the new power cord. Now, having said that, you could have loose or defective connections either in the plug on the cord or at the other end where it attaches to the motor and switch.

Again, you said the switch was new so I am inclined to not suspect the switch itself. Connections, on the other hand, could be loose.

UNPLUG THE CORD WHEN CHECKING OR WORKING ON THIS PROBLEM. IT HURTS WHEN YOU DON'T; BELIEVE ME, I KNOW.
"Making Sawdust Safely"
Dusty
Sent from my Dell XPS using Firefox.
Ron309753
Gold Member
Posts: 355
Joined: Tue Jul 01, 2008 10:25 pm
Location: Marengo, OH

Post by Ron309753 »

Ok, evidently the switch I got at the Home Depot was junk. I got a new Gardner-Bender DPST 20A 125VAC switch at Sears and now it works without shutting down, and starts every time. Yahoo!
The replacement cable I had put on it is a 14 gauge cable as is the 25' extension cord I have it plugged into. I was thinking I might need a 12 guage cable, but the 14 guage seems to be sufficient.

Thanks Rusty, Bill, and Bill.
My next question will be about lubricating this thing!
User avatar
cincinnati
Platinum Member
Posts: 1172
Joined: Sun Apr 15, 2007 6:40 pm
Location: Cincinnati, Ohio

Post by cincinnati »

Here is a video to take care of your next question. Look at #3

http://www.shopsmithacademy.com/SS_Arch ... _Index.htm
User avatar
Ed in Tampa
Platinum Member
Posts: 5826
Joined: Fri Jul 21, 2006 12:45 am
Location: North Tampa Bay area Florida

Post by Ed in Tampa »

Ron309753 wrote:Ok, evidently the switch I got at the Home Depot was junk. I got a new Gardner-Bender DPST 20A 125VAC switch at Sears and now it works without shutting down, and starts every time. Yahoo!
The replacement cable I had put on it is a 14 gauge cable as is the 25' extension cord I have it plugged into. I was thinking I might need a 12 guage cable, but the 14 guage seems to be sufficient.

Thanks Rusty, Bill, and Bill.
My next question will be about lubricating this thing!
Ron309753
Believe me the 14 gauge isn't big enough. I had to replace my standard line cord and when I did I replaced it with a 12 gauge cord. The diffference was day and night. Before my SS ran perfectly and never blew a fuse but it would bog down at times. When I replaced the cord it acted like it had new life. I have done things on it that I know in the past would have bogged it down and yet it didn't bog at all. I'm totally sold on 12 gauge line cords in a dedicated service for the SS.
Ed
Post Reply