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Power Supply Voltage Too High
« on: November 28, 2007, 01:01:12 PM »
I have an Automation Direct power supply, microstepping driver and NEMA 23 motor that came as a package. This I plan to use for the Z axis on my lathe.

The X axis will have a driver and motor from Interinar.

Problem is.......the Auto. Dir. supply is 35v at 4 amp and over 40v with no load (unregulated). This is OK with their driver but the Interinar driver is 32v MAX. I fried one some time back using the Auto. Dir. supply.

So....I used 2 supplies. The Auto. Dir. and a Sola 24v 5a. That set-up worked fine.

What I would like to do is use only the 1 supply from Auto. Direct.

How can I tap off of it and bump it down to 30v or less for the Interinar driver ?

I'm getting anxious, the rest of my GOODIES are being shipped NOW !

Thanks for all of your help, past and FUTURE.


Offline comet

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Re: Power Supply Voltage Too High
« Reply #1 on: November 28, 2007, 02:57:45 PM »
hi,
  if its a wound transformer just unwind the primary untill you get the voltage you want.
You will lose amps prorata.
  Tony
Re: Power Supply Voltage Too High
« Reply #2 on: November 28, 2007, 03:56:55 PM »
Tony,
I'd rather not hack into it. It also has a 5v output for logic that I will use later.
I was just wondering if there was a device that I could put between this supply and the other driver to lower the voltage.
Have a look at it, tell me what you think.
Thanks                                            http://web5.automationdirect.com/static/manuals/surestepmanual/ch4.pdf



 

Offline Chaoticone

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Re: Power Supply Voltage Too High
« Reply #3 on: November 28, 2007, 04:02:12 PM »
I'm not sure if it is the best option, but you could just pull a leg off the high side (35v) and use an inline resistor to lower the voltage. May put the current load to high on the PS though.

Brett
« Last Edit: November 28, 2007, 04:04:31 PM by Chaoticone »
;D If you could see the things I have in my head, you would be laughing too. ;D

My guard dog is not what you need to worry about!

Offline comet

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Re: Power Supply Voltage Too High
« Reply #4 on: November 28, 2007, 04:22:37 PM »
Hi,
  Resistors are not an elegant way of dealing with excess voltage but it will work!
  you could use a voltage regulator, there's a company called "linear" who make one that should suffice.
google it and download the data sheet,there is usually basic circuits on the sheet that do.
  Its just the regulator a couple of capacitors and a pot.
Or if you want to go silly get a couple of 555's and build yourself a pwm stepdown circuit.
have a look at this.
   http://www.eleinmec.com/article.asp?28
    Tony

Offline comet

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Re: Power Supply Voltage Too High
« Reply #5 on: November 28, 2007, 04:33:49 PM »
oh! it should have been unwind the secondary not the primary,it wouldnt affect the 5volt tap.
  Tony

Offline chad

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Re: Power Supply Voltage Too High
« Reply #6 on: November 28, 2007, 10:13:44 PM »
Unfortunately I am going to interject a little reality here. Everything mentioned will work, sorta.  A resistor will limit current, and that will cause the voltage to drop but it would have to be a huge, really, a big one, to handle the current for servo drives. A proper one would probably cost more than a new power supply.

Voltage regulators: Linear, (linear technology) does make "linear" voltage regulators, like the 7805 (a positive 5 volt regulator).
I think He is confusing the term linear (as in the technology of linear regulators) with the company Linear Technology, oof- confusing.

Ok now to the point. There is really not a good way to do what you would like to do. The suggestion of unwinding some of the secondary is in my opinion the best advice. This is what I would do. It will not change the current at all, that is based on the wire gauge and not the length. Unfortunately this is not a really easy thing to do.

A resistor just isn't an option (sorry Chaoticone ;)

Linear regulators just are not good with high current things like servo drives. It could be done but it would cost much more than the correct power supply.

So I guess the bottom line is put that supply up on ebay and go get yourself the proper supply. I would look for a multi output switching supply that does what you want. Double the max current that you think you will need and you chould be good to go. Power supplys are not the place to cheap out for servo drives.

Chad
Re: Power Supply Voltage Too High
« Reply #7 on: November 28, 2007, 10:43:37 PM »
Thanks for the input guys,
I guess I'll either get a different PS or get another Auto.Dir. driver to go with the PS I have.

No biggy, I just wanted to use the misc. components that I have on hand for my first cnc project. This is truly a learning experience and I'm looking forward to successfully completing it and getting it running with Mach.
Being made from stuff on hand, some parts are heavy... some are light but it should function well for what I expect it to do.

The next project will be well planned out in advance and the materials and components will be "designed for form and function".
I sure have picked up a bunch by watching/searching this forum.
Customer support is one thing but I am not sure that I would attempt this without the willing contributors and expert advice found in this forum.
Thanks again for the help.
I"LL BE BACK !   8)

Offline Chaoticone

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Re: Power Supply Voltage Too High
« Reply #8 on: November 28, 2007, 11:21:54 PM »
Hey Chad, where you been hiden? You get to do any more to the 5 axis monster?

Brett
;D If you could see the things I have in my head, you would be laughing too. ;D

My guard dog is not what you need to worry about!

Offline chad

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Re: Power Supply Voltage Too High
« Reply #9 on: December 01, 2007, 06:41:24 AM »
HI, sorry I have been really busy, and needed to take a little break from forums, not just here but on the other 6 I regularly visit also.

As for the 5 axis guy, I have the new head designed but haven't been working on it much lately. We are probably going to get a new haas VF-3 and the new head will probably be one of the first projects for it. 

I have been working on making 1/5 scale motorcycle rims. That is a huge pain in the butt. I had to build a 5 axis trunnion table for the mach bp clone. I will post some stuff in a couple of days. Ask Brian, he was in town and he stopped by the shop and we went out and had some beers ;)

chad