Pot Question

[AWSubie]

If it was my machine I would buy a 10,000 ohm (10k) potentiometer and hook it up and see if it works. In my experience the machines I have repaired use 10k ohm pots.

 

[Damifino]

Do you think your grinder uses same pc board and pot as this one?:

http://s3.amazonaws.com/dpec/assets...96/23-196 6-Inch Grinder Parts List Rev 9.pdf

I don't think so...different animal, mine is 8" 5amps that one is 3.5 amp.

 

[Damifino]

If it was my machine I would buy a 10,000 ohm (10k) potentiometer and hook it up and see if it works. In my experience the machines I have repaired use 10k ohm pots.

What type of machines are we referring too.

 

[AWSubie]

What type of machines are we referring too.

Inverter type welder - current setting pot

Hand held buffer - rpm pot

Portable bandsaw - rpm pot

 

[Damifino]

My voltage on all 3 wires to pot 24.5 vac, AWSubie, I guess this being a bench grinder I would need a rpm pot?

 

[AWSubie]

My voltage on all 3 wires to pot 24.5 vac, AWSubie, I guess this being a bench grinder I would need a rpm pot?

A potentiometer is just a voltage divider. There isn’t a specific potentiometer for RPM versus anything else such as in my case the current input on my welder. The important criteria is the resistance characteristic, my only point being that of the equipment I have fixed I believe they were all 10k potentiometers. one of those might’ve been 100 K but to be safe u could start with 100 K resistor see how it performs and then work your way down from there until you get the RPM you need. I just looked on Amazon and you can buy a set of potentiometers 1k, 5k, 20k, 50k and 100k for 10 or 12 bucks

 

[Industrial Toys]

Digikey is one of my goto suppliers. AMAZING company.

A pot is just a variable resistor, the two outside leads are fixed and the center one moves, changing resistance. In speed control, this is merely input to a speed control circuit, using semiconducors and the pot never sees any high current. SAME with a traditional lamp dimmer. So the wattage rating of the pot, has nothing to do with what is being controlled. A tiny pot could control the speed of something hundreds of tons!

 

[CobyRupert]

All they all variable resistors, or are some variable inductors?

 

[Damifino]

A potentiometer is just a voltage divider. There isn’t a specific potentiometer for RPM versus anything else such as in my case the current input on my welder. The important criteria is the resistance characteristic, my only point being that of the equipment I have fixed I believe they were all 10k potentiometers. one of those might’ve been 100 K but to be safe u could start with 100 K resistor see how it performs and then work your way down from there until you get the RPM you need. I just looked on Amazon and you can buy a set of potentiometers 1k, 5k, 20k, 50k and 100k for 10 or 12 bucks

Thanks... just pulled the trigger on this kit. 3sets 1k-1k Ohm Single Linear Taper 3 Pins Rotary Potentiometers Resistor with Pots Knobs Kit: Amazon.com: Industrial & Scientific

 

[Industrial Toys]

I have never seen a variable inductor used in a speed control circuit. Off the top of my head, I have only seen them in radio tuning circuits.