DC power supply

[brownk]

Hey there

I need to build a power supply for a 75volt 35watt DC motor. My mains supply is 220volt.

I want to be able to vary the output voltage to control the speed of the motor.

I also want to be able to change the motor direction

If anyone has any ideas please reply

Cheers everybody.

 

[Russlk]

Try this circuit:

 

[brownk]

Perfect

I'll get onto sourcing those parts. btw is that a 240ohm resistor after the LM317? (just making sure ).

Thanks again.

K

 

[Sebi]

Yes. All datasheets recommend this value.

 

[brownk]

power supply

I may want to adjust the voltage from 0 to 75 volts.

What would be a good way of doing this?

I was thinking of just installing a second LM317 after the first and using a second pot.

 

[Styx]

PWM those switches to vary the output voltage to the machine terminals

 

[Optikon]

Hey there

I need to build a power supply for a 75volt 35watt DC motor. My mains supply is 220volt.

I want to be able to vary the output voltage to control the speed of the motor.

I also want to be able to change the motor direction

If anyone has any ideas please reply

Cheers everybody.

If you build the schematic provided - Please check your power dissipation on the LM317 part under all operating conditions. You will be burning alot of power on that device. I would also add some heavy filtering on your output voltage.

 

[brownk]

pwm?? sorry i dont understand.

Anyway i am not going to build the reversible part of the circuit after all.


Optikon, if you mean that the circuit is not going to be very efficient im not that worried as it is only for occasional use.

If you mean that it will blow the LM317 i thought that its voltage range was 'floating'.

Thanks for your help though and if you guys have any more suggestions they are welcomed

Kenny