Question about stepper motors

SgtWookie

Joined Jul 17, 2007
22,230
Here are a couple of toroidal transformers to consider:
http://www.mouser.com/ProductDetail...=sGAEpiMZZMvwUzoUXIIvyW8HfC4QLhUedHFykF/Sx2E=
http://www.mouser.com/ProductDetail...GAEpiMZZMvwUzoUXIIvyTw34uqMHR%2bupAXftcIwciE=

Basically, 120v or 240v to 48v center tapped, ~21A out, 1KVA for both of them. Both around $167. Not cheap, but these will be quite efficient.

The days of large, cheap transformers are gone. If you think these transformers are expensive, just wait a few months - they'll be yet more expensive.
 

stirling

Joined Mar 11, 2010
52
jchal3 - It's your turkey shoot but personally before I would spend money on building a PS I'd want to know exactly the specs of the system I was building it for... and I don't think you're at that point yet.

Revisiting your earlier reply...

Stirling,
Thanks for the reply. I will do the best I can to answer your questions. First the motors are pacific scientific powerpac motors. they are 1.8 degree step motors. 7.5 amp bipolar series, that run at 65 vdc. Po whatever that is) is 337watts. and they spin at 1350 rpm. All three motors are the exact same.

second, the drivers are pacific scientific 5410 drivers. They run on 12-75vdc with 5 vdc logic. The are set to microstep at 25:1

Third,

My power supply is a 36v 4.2amp 150watt power supply. It is 110v input and I believe it is regulated.

Fourth,

I am driving my system using Mach 3

Fifth

the motors are direct drive to acme thread, so it is 6 rotations per inch. All three axis are the same.


Note:
When building this machine I was lead to belive that running this power supply would work as long it is was at "lowish" speeds. I have had the problem at speeds as low as 200mm per minute. If it has to be slower than that, then I need to change the power supply, because that is painful to watch.
It is unusual (though not unheard of) to have a stepper marked with a voltage like 65V and my question would be what do "they" mean by this? It's highly unlikely that this is the RATED voltage. If it is then it renders a 65V supply though a chopper drive completely pointless. In fact the chopper would not work so there's more to this than meets the eye. It "may" be that this is the suggested drive voltage given the motor's inductance - but I'd want to KNOW that - not guess it.

Secondly you say the logic level of the drivers is 5V - and yet according to the data sheet posted, if I've read correctly it's 12V. If that's the case your optos probably arn't responding as they should.

As I've said earlier Mach3 is "unlikely" to be giving a good step stream from a laptop - but you may be lucky.

etc. etc.

You can't (unless you're very lucky) fix something when you don't fully understand the problem. Just my two whatnots.
 

shortbus

Joined Sep 30, 2009
10,045
shortbus,

I think I may have been the one to give you the manual. I was looking at some posts from when started building this machine, and you weighed in on those conversations as well. Thanks for the help, and good hearing from you again.

I am going to attach the manual here as well
I remember you now, your the guy with the NEMA 42 motors, right?

Thats not the manual that I have, never seen that one. Here is the one I have. Appendix 'C' is for the power supply and pages 2-22/2-23 show the correct way to hook-up the computer in-puts.

Hope this helps, and please post photos of your CNC.
 

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