How to controll speed on electric motor...

[Tags]

I know this isnt a tractor question, but, there is such a vast majority of knowledgeable people here I thought I'd give this a shot. I recently purchased a used Airflo MSS tailgate sander with an electric motor. It is turned on and off with a toggle switch but I want to be able to slow down the spinner/conveyor when sanding a driveway. I contacted an Airflo dealer and was quoted $650.00 for a speed control switch but I think that sounds a bit steep, anyone have any ideas??

 

[KYErik]

What type of electric motor is it? A drill/circular saw type motor (noisy with brushes) or a quiet brushless motor (like would run a bench grinder)?

If it is a drill type motor, you can likely pull the variable speed resistor switch out of another piece of equipment with a drill type motor that is rated for the same number of amps.

If it is a brushless motor, I think you will need a Variable Frequency Drive (VFD). Slowing down the cycles (Hz) of the line voltage will reduce the motor speed, but it may lead to overheating since the internal fan was designed to run at rated speed.

 

[Tags]

What type of electric motor is it? A drill/circular saw type motor (noisy with brushes) or a quiet brushless motor (like would run a bench grinder)?

If it is a drill type motor, you can likely pull the variable speed resistor switch out of another piece of equipment with a drill type motor that is rated for the same number of amps.

If it is a brushless motor, I think you will need a Variable Frequency Drive (VFD). Slowing down the cycles (Hz) of the line voltage will reduce the motor speed, but it may lead to overheating since the internal fan was designed to run at rated speed.

Sorry,didn't even think of mentioning that. It is like a starter motor, 12volts and and I think it is 1/4hp

 

[murphy1244]

You need a reostat and a darn big one at that.

 

[BobRip]

You might try running it off of a six volt battery. I think this would give you a little below half speed. Take the motor to an auto parts store and see if they will let you test this. Of course you would have to charge the battery periodically. You might try putting a car headlight in the battery to motor hot lead. Use two in parallel if it's too slow. You could actually use your vehicle lights. Just connect the motor between the battery positive and the positive lead of the lights. The motor will run when the lights are off. I have not tried any of this. I just know something about electricity.

 

[Soundguy]

rheostat? please.. how barbaric.

PWM for sure....

handfull of IRFZ40's and some perfboard and etchant will do ya...

soundguy

 

[BobRip]

rheostat? please.. how barbaric.

PWM for sure....

handfull of IRFZ40's and some perfboard and etchant will do ya...

soundguy

Please attach a schematic, parts list, and pcb layout. Easy for you.

 

[Tags]

rheostat? please.. how barbaric.

PWM for sure....

handfull of IRFZ40's and some perfboard and etchant will do ya...

soundguy

Soundguy, what you said sounds great to me....if I could understand it....I also forgot to mention I am not well versed in the ways of electricity. Could you explain what you are saying like you're talking to a two year old?

 

[k0ua]

You need an SCR (Silicon Controlled Rectifier) speed controller. Either build your own SCR based controller. or buy something. you need to know the current draw of your sander in AMPs. I am guessing about 10 amps but could be more.

Silicon-controlled rectifier - Wikipedia, the free encyclopedia

12 volt speed control | eBay

dc speed control | eBay

12V-40V 10A PWM DC Motor Speed Controller w/ Knob - Free Shipping

Do some research and get back with us..

James K0UA

 

[BobRip]

You need an SCR (Silicon Controlled Rectifier) speed controller. Either build your own SCR based controller. or buy something. you need to know the current draw of your sander in AMPs. I am guessing about 10 amps but could be more.

Silicon-controlled rectifier - Wikipedia, the free encyclopedia

12 volt speed control | eBay

dc speed control | eBay

12V-40V 10A PWM DC Motor Speed Controller w/ Knob - Free Shipping

Do some research and get back with us..

James K0UA

By the time you build this yourself you will wish you had paid the $250.