PDA

View Full Version : dc drive help



dj merritt
10-12-2009, 06:35 PM
Hello I am building an animated ghost, And I was wanting to know if anyone knows how I can run a 90 vdc motor with 120 vac. The motor is 1/10 hp 268 rpm and 90 vdc how can I connect it to 120vdc. would also like to control the speed of it. Thanks

DynamoBen
10-12-2009, 08:08 PM
Hello I am building an animated ghost, And I was wanting to know if anyone knows how I can run a 90 vdc motor with 120 vac. The motor is 1/10 hp 268 rpm and 90 vdc how can I connect it to 120vdc. would also like to control the speed of it. Thanks

You would need a 90Vdc power supply. BTW you didn't mention current draw (amps) which plays an important roll in finding a power supply.

dj merritt
10-13-2009, 01:37 AM
@ full load 268 rpm max amps stats say 1.1 amps. I am thinking I could do it with a 25 amp rectifier and an inline 3uf capacitor, and then add a dimmer control.
what do you think ??

DynamoBen
10-13-2009, 02:05 AM
Dimmers don't do speed control very well, unless of course you are talking about a PWM (DC) dimmer. In the past when I've done motor control its been PWM via a FET with a refresh rate around 10K, anything lower caused the coils to hum.

dj merritt
10-13-2009, 02:19 AM
A dc pwm I agree but wht is the fet im lost lol

DynamoBen
10-13-2009, 11:03 AM
I used the FET (MOSFET) to drive the motor because the motor I was using could draw up to 5A when stalled.

bcadman
10-13-2009, 12:37 PM
What about using some small relays and power resistors on the AC side of a rectifier. Keep in mind that small inexpensive relays can handle AC better than DC.

What kind of controls are you looking for?

How many different speed points do you need?
Do you need the motor to switch directions?
How do you plan on operating this motor? Using a computer?

dj merritt
10-13-2009, 01:38 PM
What about using some small relays and power resistors on the AC side of a rectifier. Keep in mind that small inexpensive relays can handle AC better than DC.

What kind of controls are you looking for?

How many different speed points do you need?
Do you need the motor to switch directions?
How do you plan on operating this motor? Using a computer?



I want to be able to go form 0-268 rpm with the control of a knob, do not need reverse.will be control by human hands not PC. the reverse ! I have alredy built a shaft arm so it can move forward and backwards. I fugured it was cheaper to do it that way, also dont have to worry about going to far out.

bcadman
10-14-2009, 08:10 AM
If you need to have variable speed control, you may consider KB Electronics.
I have used KB DC drives a few times with a lot of success.
kbelectronics.com
~$70 for KBIC drive... may be less on ebay or something.
do a google on "kb electronics kbic" and download the pdf.
If you decide to go this route, let me know and I can help you.