Variable Speed control of 24v DC motor

[Billy Wright]

Hi, I am trying to design a circuit to allow variable control of a 24V DC motor but I have very limited knowledge of this subject, I have researched and I have found circuits that work for 12V motors but I am not sure how I would have to change them to make them suitable for a 24V one. One circuit I found is this one: 

http://www.engineersgarage.com/contribution/anjali/speed-control-of-dc-motor

Does anybody know of how I would have to change the resistance for my 24V motor to operate properly?

Thanks in advance

[Ashutosh Bhatt]

what is ur application?

how you want to control speed of motor?

what is current rating of motor?

[nischay malhan]

Pulse width modulation(PWM) will work for both 12V and 24V dc motor

[Billy Wright]

The motor will be connected to a wheel which will be caused to rotate, I would like to be able to make the the wheel rotate at different speeds. I am unsure of the rated current but ideally I would like to keep it below 0.33 Amps if possible. 

[Billy Wright]

Do the resistances and capacitance not need to be changed to prevent the circuit from burning out if the voltage is higher?

[nischay malhan]

You can use motor driver for PWM control of dc-moto. Its works for 12-24V dc motors. L293D is one such motor driver u can use for upto 30V motors

Just make sure, they're good for under 600 mA since that's the limit of this chip

 

[nischay malhan]

Or better use L298N, it has max current upto 4A and will work for 24V dc motor

[Billy Wright]

Will this chip work in the circuit shown in this link without changing the resistors or the capacitors?

[nischay malhan]

Dear Billy, if u want to use the circuit mentioned in the link, you can use the same circuit as it is for a 24V dc motor. The problem being your dynamic range of controlled speed will be less. In this circuit what happens is that the output from the NE555 IC is fed into the DC motor according to the resistance provided by the potentiometer. So if you implement the same circuit with a 24V dc motor at output, the maximum speed that the motor will rotate at will be lesser compared to a 12V dc motor.

There is also a possiblity that the motor might rotate slowly as the signal being fed into the motor is not sufficient to drive it. You can go ahead and give it a try without the fear of damaging anything. 

But if you use the L298N, then there will be no need to make any circuit. These are motor drivers or H-bridge boards on which you can connect your motor directly. You just have to provide sufficient power to these boards. If you wish to control the speed of you motor with a micro-controller or an Arduino, using L298N  is a better option than NE555.

Hope this helps!!

[Billy Wright]

Ah right, thank you very much, I need to make the circuit myself as it is for a university project and to get a better mark I need to have made the circuit myself. Thanks for the help though you have been very informative.

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