how do i make my bench grinder slower? would a dimmer work or

>>1052400
Depends on the motor, a brushed motor can have a variable speed attached to it but something like the induction type motors use the AC frequency to determine their RPM and lower voltages tend to make them overheat.
So- if you can modulate the freq going in that might work but wouldn't guarantee anything not burning out.

Only option you have is to either buy a new grinder or build yourself a belt drive grinder.

>>1052400
>would a dimmer work

no

>would it ruin the motor?

yes

>>1052400
single phase grinder?
a smaller wheel for lower edge speed is all you can do.

>>1052400
ignore the haters, if its a dc motor you just need to reduce the voltage. You can do this by adding resistors, or even better get a variable resistor (potentiometer).
If it is then ur fuggd

>>1052400

You'd need a single phase output VFD, you'd probably also need to mod the starter capacitor circuit.

Hardly seems worth it.

>>1052400
It would certainly ruin the dimmer very quickly, they aren't designed for inductive loads.
All motors are inductive by nature but if you have a truly ' inductive' motor then its speed is determined by your supply frequency rather than voltage and so you need a VFD (variable frequency driver)
If its a brushed ac motor then you can use a suitably rated transformer, simply calculate the voltage you require based on the impedance and current found by calculating the force required to spin at the speed you need. Alternatively an autotransformer (nothing to do with cars before any Americans get flustered) to vary the voltage to your hearts content.
A potentiometer is fucking stupid idea because it would need to be huge and be able to handle a lot of power. A volume knob type deal would melt you want one of those stupid big wire wound ones they keep in museums

>>1052470
>if its a dc motor you just need to reduce the voltage
>>1052400
>my bench grinder

bench grinders don't use DC motors

install a smaller wheel

File: IMG_2281-R2.jpg (2MB, 2472x1996px) Image search: [Google]

2MB, 2472x1996px

>>1052498

>>1052520
Notice the speed control?
If OP had that style he wouldn't be asking

File: 2978234953.png (196KB, 1280x800px) Image search: [Google]

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Google: V/F single phase motor controller

<iframe width="560" height="315" src="https://www.youtube.com/embed/P9UjxG8sN1c" frameborder="0" allowfullscreen></iframe>

>>1052530
fug
apparently that is not how you do that

>>1052531
Just post the link, no need for any embed shit.
https://youtu.be/P9UjxG8sN1c

>>1052522

Most of them are single phase input, not single phase output.

https://www.driveswarehouse.com/nes1-002sb-2681
Boom. Done.

>>1052400
If you can into electronics and it's a normal universal brushed motor, look up phase angle control with a triac. A company named littel fuse has a whitepaper on some circuits you can build, just search google. If it's an induction motor, you need a variable frequency drive iirc.

You can't use a normal resistor/potentiometer because it would just burn up from the wattage. However, if you want something really simple you could make a liquid rheostat/liquid resistor. Not sure if it'd work with an induction motor, but it would definitely work with a universal one.

>>1052559
12 Rated Output

12.1 Voltage
200 - 240VAC

12.2 Phase
3

12.3 Frequency
0.5 - 400 Hz

>12.2 Phase - 3

>>1052576
Also to add, if it's a universal motor you might be able to get away with adding just one diode to the circuit which would half the power, and give you two levels of power.

>>1052579
It would work.

>>1052587
>It would work.
9.4 Output Current (Amps)
1.4

I doubt it.

A typical bench grinder similar to OP pic is 120vac @ 4 to 6A.

>>1052587
>3 phase VFDs don't monitor line balance


The most reasonable DIY solution is a belt system. You couple replace one of the wheels with a pulley and find an extra motor somewhere. A treadmill motor would give you additional speed control (because muh DC) and you could use a pulley to step it down.

Get a router speed control from Harbor freight. Like 15 bucks.

I have a Sears-brand bench grinder I bought that has a variable-speed control knob on it. Cost like $140 or so IIRC. I chose it mainly because of the variable-speed feature.
I occasionally turn it up maybe 2/3 of the way, but usually use it down near the low-end setting up to about 20%.

Cheap grinder wheels only cost $10 - $15, while good ones cost $50 - $60. Cheap grinder wheels tend to explode a LOT more often than expensive ones.
If you just run them at a lower speed, you greatly decrease the risk of the wheel exploding.

>>1052650
>Harbor Freight Router Speed Control
You can try it and see. Just testing it for a few seconds won't hurt a motor.

Two rules about using the HF router speed controller:
1. It can't be used on anything that already has a speed-control knob or speed-control switch on it.
2. If you try it and the motor spins "jerky" (especially when you adjust the speed knob up and down) then it's not the right kind of motor and you should not use it at all. The motor should always spin perfectly smooth.

On the variable-speed setting it will alter a motor speed from about 30% up to about 95%. Some motors will stall before you can dial them all the way down to the lower-end of the controller's range.

If you use it on a synchronous motor, two things happen.
One is that it doesn't hardly alter the speed at all (and you get the motor jerking).
The other is that the motor gets REALLY hot, really fast. It is this high heat that will damage the motor.

It works on a 1/4" electric die grinder I have, and it works on a little shop-vac I have also.

It can also control incandescent lights and electric heating elements, should you have the need.

>>1052650

It's an induction motor, not brushed. This won't work. Neither would the 3 phase output VFDs be likely to work.

The unobtainium single phase output VFD wouldn't work well unless you disconnected the starter capacitor (you'd start it by spinning it up from 0 instead, so no capacitor needed).