7" electric grinder - reversing rotation?

Use it from the rear!

Nick

Turn the plug over..

Reversing the connections to the brushes or fields, whichever is easier, should work if the plug idea doesn't.

John

Probably this grinder has an induction motor. I've never seen a bench grinder with a commutator motor. I suspect someone has wrongly connected the windings under the terminal cover. If it is a single phase induction motor then (provided it isn't dual voltage) it will have two windings which can be identified using a multimeter. You then need to reverse the connections to ONE winding to reverse the rotation.

Chris

Er, sorry, perhaps Grant didn't mean a bench grinder. The word "big" lead me to think of bench grinders. If it's an handheld grinder then it will most likely be a commutator motor, and in that case John's second suggestion should work.

Sorry!

Chris

That's illegal in many states here. Oh, wait, you meant... Never mind. ;)

------------------------------ REAL men don't need free plans ------------------------------

It might be possible this grinder, if a bench mount, was used with a buffing wheel. Often bladesmiths will reverse the direction of the spindle so a buffing wheel can not throw a blade down toward their feet or legs. The idea is to work off the top of the wheel, with it turning away from you, when buffing or sharpening. This may be the same usage of other trades but I'm not aware of them.

Dennis in nca

Hmm.. good point. I was thinking of an angle grinder but for all we know it could be a bench grinder. Have to wait and see I guess..

John

OK, I tore it down. It turns out someone replaced the power cord and didn't know what they were doing. There are two brushes, and the brush holders themselves are removable. I removed the brushes, took the brush holders loose, swapped their position (paying attention to the routing of the wires inside the stator cavity) and reassembled. Now it runs the correct direction, and the tooling doesn't fly off -- a BIG improvement!

I'm beginning to see why the seller sold this so dang cheap. It's a nice grinder, though, all metal gearing, ball bearings everywhere, switch works perfectly. The plastic on the handle housing is cracked around some of the screws, though, so it may not hold up indefinitely. Probably the same bozo who reversed the brush positions.

GWE

Grant Erw> I bought a big old electric grinder recently. It looks vaguely like an

It wasnt me was it? Or did someone else get the big angle grinder.? I never opened the one I passed on to someone...

Gunner

"Considering the events of recent years, the world has a long way to go to regain its credibility and reputation with the US." unknown

Sounds like bondo or other good tight holding material to save the plastic.

Martin