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Stir Plate Wiring Help

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DaleJ

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Hey

Can someone with electrical talents help me out?

I'm putting together a stir plate.

I have a 9VDC power supply and a 12VDC .21Amp fan.
In between I have a toggle on/off switch and either 1 or 2 25ohm potentiometers.

No matter how I configure it I can't get the potentiometers to vary the fan speed.

Any suggestions?

Thanks.

Dale
 

Bernie Brewer

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Run the positive DC wire from the source to one side of the switch. Then go from the other side of the switch to one side of the Potentiometer. then go from the other side of the POT to the motor.
Run the negative DC wire directly to the motor.
What you are doing is wiring the switch in series with the POT.


Clear as mother's milk, right?:)
 

slnies

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Bernie Brewer said:
Run the positive DC wire from the source to one side of the switch. Then go from the other side of the switch to one side of the Potentiometer. then go from the other side of the POT to the motor.
Run the negative DC wire directly to the motor.
What you are doing is wiring the switch in series with the POT.


Clear as mother's milk, right?:)
And if that doesn't work a dimmer switch will. That is what I use, because they are cheap.
 

Bobby_M

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Pots usually have three terminals. One wire has to go to the center pin. The other goes to one of the other pins. If you connect to the two outter pins, the resistance is fixed to the max of the pot.
 
OP
DaleJ

DaleJ

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Right, the negative is directly wired to the fan, and the positive goes through all the resistance.

I thought I'd tried every combination of the pots terminals, but i'll retry those.
 

SCmedic

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Run the positive DC wire from the source to one side of the switch. Then go from the other side of the switch to one side of the Potentiometer. then go from the other side of the POT to the motor.
Run the negative DC wire directly to the motor.
What you are doing is wiring the switch in series with the POT.


Clear as mother's milk, right?:)

Thanks, for some reason I wasn't getting it until I read this
 
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