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dednnyholtmo · Aug 28, 2007, 09:06 AM

How do I reverse the direction of rotation of a bench grinder. I want to use it for sharpening of wood-working tools and have been told the direction the grinding wheels spin should be counter-clockwise:confused:

KISS · Aug 28, 2007, 11:22 AM

The info is usually printed on the nameplate or just under the cover of the motor junction box on the motor. Motors either have links or wires. Most of the times the wires will appear to be all black, however if you look carefully at the insulation you will see numbers printed on the insulation. I've always used the name plate.

Here's what I dug up on the net:

Reversing and Repair of Electric Motors

dednnyholtmo · Aug 28, 2007, 01:53 PM

Originally Posted by dednnyholtmo

How do I reverse the direction of rotation of a bench grinder. I want to use it for sharpening of wood-working tools and have been told the direction the grinding wheels spin should be counter-clockwise:confused:

Thanks for your response. The attachment was probably very clear to an electrician but I couldn't make heads or tails of the wiring diagrams.
There are 4 wires running into the winding; a black or hot, two red from I assume a capacitor and a white. It is not obvious what is attached to what. However, I am confident that if I swap attachment of a couple of wires I will reverse rotation of the motor. The question is, which two?

KISS · Aug 28, 2007, 02:24 PM

The motor is probably not reverseable. This would be done to save manufacturing costs on a high volume item. Your assessment, I believe, is valid.

BTW, if you turn the grinding wheel over you'll achieve the same thing. I should have caught that. There is no need to do it electrically.

sand420 · Apr 4, 2011, 05:03 AM

We can do it in two way;s
1-if we revers the suppl current to armatur.
2-if revers the current supply to field wnnding.

Stratmando · Apr 4, 2011, 05:26 AM

Most all bench grinders rotate the correct direction, They all rotate counter clockwise depending on which way you look at the wheel.
Facing the wheel, it should be rotating down, not up.

Stratmando · Apr 4, 2011, 06:04 AM

Kiss, in that link you provide, near the bottom of the page, just above Motor Protection and Magnetic Starters, they show connecting 1 and 4, then 2 & 3 together and the 5 & 8 for reversing.
I believe they mean connect 1 & 3, and 2 & 4, then the 5 & 8 are for reversing?

billlyh · May 11, 2011, 02:36 PM

You can't turn just the wheel over, it will still turn the same way... you'd have to turn the motor over, leaving the wheels intact. You could, then, change ends with the wheel, and have reversed the direction of rotation.

billlyh · May 11, 2011, 02:38 PM

Funny! No matter whether it is turning clockwise, or counterclockwise, one side of the wheel is turing up, the other turning down... so, facing the wheel, it could turn either way, and still apply to your comment.