Getting started electrically diagnosing your Shopsmith motor

[everettdavis]

There are a number of posts that discuss disassembly and repair of the various Shopsmith motors. Some less familiar with electrical repairs may first believe they lack the electrical knowledge.

The main focus of this post is to make you more comfortable using the meter to test the motor and capacitor, and Fluke does a very good job of that in the second PDF document I posted. The Fluke document obviously is using Fluke test equipment, but you can find lower cost tools at many hardware stores that will function for your purpose.

Even if you determine your motor is beyond your own ability to service, don't discard it. Someone else in the Shopsmith forums may be able to completely rewind and restore it for you, or may even buy it from you for parts. I don't do those level of rewinding services on Shopsmith units I am servicing for myself, but a number of forum members can and do excellent work repairing motors for others, and you can learn how to do it yourself if you want to.

First: "Getting started electrically diagnosing your Shopsmith motor"

Getting started electrically diagnosing your Shopsmith motor.pdf

(459.93 KiB) Downloaded 6901 times

Second: "Flukes Guide on Motor Troubleshooting"

Flukes Guide on Motor Troubleshooting.pdf

(280.88 KiB) Downloaded 679 times

[beeg]

THANKS. That ought to be valuable to a number of people.

[JPG]

Kudos on posting the pdfs.

However I take exception to the low gear start up analogy.

What is actually occurring with the start winding is to bias the direction the armature rotates. Without that bias the run windings will cause it to merely hum and maybe drift slightly. The run windings will cause the motor run in either direction once it is 'started'.

These comments apply to the shopsmith motors.

[everettdavis]

JPG I defer to your knowledge of Shopsmith motors regarding the analogy! You are a trusted repository of Shopsmith knowledge and experience.

Everett

[everettdavis]

I was wondering if anyone would pick up on the photo I used from Bill Mayo's post showing the capacitor on the back. That GE motor actually uses a start relay opposed to a centrifugal switch to accomplish the start up.

Since no one has mentioned it, I thought I had better mention it should you have one of these motors on your Mark V.

I didn't discuss the start relay in the text. Many systems, especially air conditioning compressors such as the one on your home likely uses a start relay, often called a 'contactor' to help start the compressor motor for example.

Update: JPG reminded me in a PM that those Air Conditioning relays even are controlled by separate low voltage circuit and a thermostat.