Spinning a servo

[shintai]

This may be a simple question but i'll ask anyway.

I have a DC servo motor i got from an indexer at work.
The encoder circuit has a short in it somewhere that put the machine in a fault state all the time.
My question is... can i use the servo as a normal DC motor? or does it require a controller like a stepper?
My goal is to use the motor simply as a "turn on turn off" motor in a homemade Drill press, as i think it will have the nessasary torque, but won't require the use of the encoder.

Thanks
Kevin

[Al_The_Man]

Yes, but it will depend on the type of controller you have, or intend using, does the motor have a tach?
If the ampifier allows the use of velocity mode, you can but you may find that without a tach feedback the speed will vary somewhat under load.
Al

[shintai]

So it will require some sort of controller?
If so i may be better off getting a DC motor for my drill press app and saving the servo for a use where its abilities would have a point. I'd just need to replace the encoder.
As for does it have a tach.. I really don't know. Guess i need to do more HW on the servo itself..

[Al_The_Man]

Originally Posted by shintai So it will require some sort of controller? .

I assume the idea is to get variable speed so, yes you will need a controller of some sort.
Al

[shintai]

I was planning on useing a belt driven pully system to the shaft with different sized pullys similar to the Drill Presses at work for change the speeds. basically i just want to be able to use the motor as a motor at a constant speed with the best use of the servo's torque. I was using a simple stepper motor with a little homemade controler that just spit steps at it to make it spin, but the stepper doesn't have much torque.

Basically i just want to turn the servo into a normal DC motor. Apply voltage to get forward movement.. apply reverse voltage to spin it backwards.
thanks again.
Kevin

[ESjaavik]

If it is a good servo motor the speed will be mostly dependent on the voltage you apply. Much more so than a non-servo motor. What Al wrote, is true. I just point out that it will be better in this respect than most common DC motors, and probably a good spindle motor.

[shintai]

so can i just apply voltage to it to turn it?
or does it need pulses or any other factor besides just basic power to get it to turn?

[Al_The_Man]

You will need a DC supply suitable for the voltage & current rating of the motor. Plus fusing etc.
Al

[shintai]

right just normal PSU requirements like i would have to build for a DC motor.
do i need to worry about the encoder pinouts or anything or just the positive and negative terminals of the motor?

[Al_The_Man]

You dont need the encoder. You might want to wire a reversing contactor though.
Al

[shintai]

ok thanks
I'll try to get it wired up and test spin it the beginning of the week and update you then
thanks for instilling a little bit of knowledge into a thick novice head

[unterhaus]

There are a lot of DC motor speed controllers on Ebay. Seems like they don't usually go for that much. http://tinyurl.com/4jk75 If you really get obsessive, drives are scattered all over the business and industrial section.

Otherwise you just need an unregulated supply.