DC Motor Field Current Speed Control

[OvaR8ed]

I have a Geared DC Motor rated 12V, 0.6A, 180RPM, 3kg.cm, 66% Efficiency. I measured the impedance of the disconnected motor at 45 Ohm.

I want to use it with a with a simple 12V 1A DC Power Supply in a Field Current Control Circuit to be able to dial in variable speeds.

Will the circuit in the attached diagram work?

What are good Theoretical Resistance values to start with for R1 and the Potentiometer to give me a wide range of speeds with no load on the motor?

For which Wattage should the Resistor and POT be rated to deal with the currents correctly?

Thanks in advance!

 

[Averagesupernova]

That circuit won't do anything. The resistors are simply another load on the 12 volt supply.

 

[OvaR8ed]

Yeah, I realized that. It could work if you limit your current at the power source, but that will over complicate things.

I'm rather going with a simple 555 Pulse Width Modulation circuit...

 

[Crazymechanic]

first of all yes for high amps a pot will be a waste of enrgy you have to use switches like transistors, the other thing the device needs to be in series with the motor , you circuit as you probably realized by now is in parallel with the motor so the motor would still go full speed.

 

[alphy]

I cannot provide a definitive answer without further information and testing. However, I can offer some suggestions and considerations.

Firstly, the circuit in the attached diagram appears to be a simple voltage divider. This may work for basic speed control, but it may not provide precise or stable control. Additionally, the use of a 12V 1A power supply may not be sufficient for the motor's rated 0.6A current. It may be better to use a power supply with a higher current rating, closer to the motor's requirements.

As for the theoretical resistance values for R1 and the potentiometer, it would depend on the motor's characteristics and the desired range of speeds. It would be best to consult the motor's datasheet or conduct experiments to determine the appropriate values.

In terms of wattage, the resistor and potentiometer should be rated to handle the maximum current that will flow through them. In this case, it would be best to use components with a wattage rating higher than 1W.

Overall, it is important to carefully consider the components and design of the circuit to ensure safe and effective speed control for the motor.