Plug-in Speed Control?

Rick Marchand

Rick Marchand

Donkey on the Edge
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Jan 6, 2005
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Has anyone tried something like this to get variable speed performance from a single speed grinder?

43060.gif


http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=43060

It says that it works for AC/DC motors up to 15Amp. I have a Grizzly 1hp, 14amp, 2x72. For $20 I could just try it out, but I'd hate to unknowingly ruin the "Grizz" with this thing.

Can any of you grinder buffs advise me... or point me to someone who can?

Rick

Here is the grinder I want to use it on...

DSC_0156.jpg
 
That probably won't work. I am also looking for the answer, without buying a 700 buck variable DC conversion.

I bought a huge 20 amp variac, that varies the incoming 120vac, the output is from 0v-140vac.
Plugged my single speed Wilton grinder, and it does not work. Until you get it down to 40vac, and the power drops off too much.
I was told that you need to have a control box that varies more than just the voltage.
Dan
 
I was afraid of that. Seems those $700 conversions would be put out of commission if it were as easy as a $20 purchase.

...... but I'm still hoping......

Which brings me to the second question...

Could this mess up my machine if I try it out?




Rick
 
From what I understand, those type of AC speed controllers will slow down your grinder, but sacrifice all of your torque. I don't think you'll find if very useful as you slow it down. And as to being harmful, I don't have any idea.

My understanding is that if you want to have variable speeds on an AC motor, you either need step pullies, or a VFD and a 3 phase motor. That's definitely hard to do on a direct drive grizzly. I still use my grizzly, but most of my metal work is now done on my variable speed 2hp KMG. You'd have to find a way to deconstruct and rebuild the grizzly with step pullies if you wanted variable speed with the same torque.

--nathan
 
Some folks have made different diameter drive wheels out of plywood for the grizzly to control the speed. This is obviously less practical but interesting.

thanks
Rick
 
They wont work. I bought one for a saw I thought would slow it down. I still have it. It wont work. It is still in my tool box, Bottom drawer. That is my Junk drawer.
Save your pennies and get a KMG.
 
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