MechMate CNC Router Forum

MechMate CNC Router Forum (http://www.mechmate.com/forums/index.php)
-   702. Power Supplies (http://www.mechmate.com/forums/forumdisplay.php?f=10)
-   -   Why not use an adjustable, regulated power supply? (http://www.mechmate.com/forums/showthread.php?t=829)

Bob Cole Wed 29 November 2006 15:20

Why not use an adjustable, regulated power supply?
 
I am wondering the viability of one of these units.

Agilent 6626A DC power supply

Does anyone here know whether this could be used for my MechMate project? Will these adapt to this type of CNC setup?
Would I be better advised to just get a constant source DC power supply.

I have found a source for several of these at an auction at greatly reduced prices from what they sold for new.

Ineed quick answers as I ony have about 24 hours left to bid if these might be a good choice. THANKS, Bob C.http://www.mechmate.com/Forum/messages/17/2490.jpg

Mike Richards Wed 29 November 2006 15:41

Bob,
I've never used, or even seen the Agilent 6626A DC power supply, but I did a quick Google search. It's not something that I could buy to run a CNC machine. The page that I saw lists the unit as having four outputs, two at 25 watts and two at 50 watts. That would work well in a lab where you needed high precision at low wattage. To drive steppers, you want high wattage without much regard for precision (assuming that a few volts is precise enough).

Bob Cole Tue 06 March 2007 17:46

Gerald/ Anyone:

Would this unit be something that could be a substitute for building my own power supply as Gerald has provided plans for on this forum?
http://www.mechmate.com/Forum/messages/17/3628.jpg

I have the ability to pick up one, or several of these New Old Stock never used from a local electronics company. I am unfamiliar with power supplies, and was wondering whether buying one of these would save me creating a home made power supply.

Any imput is greatly appreciated.

Bob C.

Mike Richards Tue 06 March 2007 21:10

Bob,
There are two things that you have to know about power supplies before you can determine whether a power supply is a good fit.

1. Does it provide the proper voltage?

2. Does it provide enough current?

The photo shows a laboratory power supply. Usually a laboratory power supply can be set to an exact voltage at a low to moderate current. Steppers like lots of current, compared to most electronic devices. The power supply that I'm using on my test bench as a stepper driver provides 10A. That might be more than necessary, but it works.

Gerald_D Tue 06 March 2007 22:10

I wish I had one of those! Overview, Data sheet.

The photo that you show is of a 3-phase supplied unit (3 input circuit breakers - do you have that?

But the number under the Voltage window seems to be TCR300S9 which is single phase according to the links above.

As Mike says, you have to know your stuff before considering this animal. You could easily end up adjusting the volume and colour of the smoke with the knobs provided.

Bob Cole Fri 09 March 2007 07:30

Gerald:

LOL the smoke and size of the cloud might fill my shop...

Am I correct in what I am picking up here, that you folks are building your power supply for around $80-$100 U.S. ?

can it be that inexpensive to put one together/

Gerald_D Fri 09 March 2007 07:55

Yes, we are building power supplies at well under $100. And they mostly work better than the fancy "regulated" versions because they don't complain about short overloads - they just ride the punches.

We make a big issue about how dangerous they are to build, because that is our duty. In reality, they are one of the easiest things to do when building your own CNC system.

kalimero Sat 29 March 2008 09:36

1 Attachment(s)
From another thread:

1 more question:
can Iuse any type of power supply with output like :48-50 V 800W.
I have one whit this label on box.

Richards Sat 29 March 2008 17:08

That power supply should work. You will probably need to add an external capacitor to help smooth out the ripple. A capacitor of at least 10,000uF will be big enough to help. 15,000uF @ 65V (working volts) would be better. The ripple is caused when the load (stepper motors drawing lots of current) drains the small on-board capacitors faster than the power supply can handle the current drain. (Most designers add an external capacitor to switching power supplies.)

Gerald D Sun 30 March 2008 00:00

It looks like a Tyco NP0800 Datasheet.

Will take some getting used to the 3.5 second startup delay. Hope you can access the output terminals. Otherwise a fine supply with the capacitor Mike is proposing.

kalimero Sun 30 March 2008 04:13

Can I use this one :

http://search.digikey.com/scripts/Dk...name=P10025-ND

Gerald D Sun 30 March 2008 05:38

That one will work, but how will you attach the wires? Rather use one with screw terminals.

kalimero Sun 30 March 2008 12:57

Quote:
Originally Posted by Gerald D View Post
That one will work, but how will you attach the wires? Rather use one with screw terminals.

I can open and connect wires inside :rolleyes:

Gerald D Sun 30 March 2008 23:07

These "switch mode" power supplies, like you have, often have a fan inside for cooling. The covers must be on for the cooling air to flow correctly. We once burnt such a power supply because the fan had collected too much dust - they are not easy to keep clean.

dmoore Wed 11 June 2008 16:39

Why not use an adjustable, regulated power supply?
 
Quote:
Originally Posted by Gerald D View Post
Do the calc of voltage and get a result of 68V. Look at the options
from local suppliers and see that he stocks 50V or 70V supplies.

A cautious person would pick the 50V supply. I am tempted to pick the
70V and adjust the current if heat is a problem.
The best of all worlds:
http://www.web-tronics.com/hedureli0dcp1.html
0-120 DC/0-5A

smreish Wed 11 June 2008 18:50

...except the toriodal transformers we use for stepper/servo use are typically of the "unregulated" type - not regulated as you have linked.

domino11 Wed 11 June 2008 19:35

Actually a regulated supply will outperform a similar supply of similar VA. When you load an unregulated supply its output voltage will drop and the power into the load will drop proportionately. A regulated supply will maintain its output voltage over its rated power. This will give you more consistent and stabke voltage to your drivers. The drawback is that regulated supplies are more expensive and complex than an unregulated supply of the same VA. Regulated supplies are also a little less efficient as the regulation devices in the supply must dissipate some power to do the regulating.

Gerald D Thu 12 June 2008 00:52

Regulated supplies have too much internal protection for their own sensitive electronics/electrics/cooling/fan. They often trip out at the slightest provocation. (we burnt one that got clogged with sawdust).

Nothing "trips out" a simple un-regulated supply consisting only of a transformer, rectifier and capacitor. This is an agricultural tractor of a supply - a real workhorse.

costas srl Mon 22 August 2011 04:30

1 Attachment(s)
Hello
I want to fix an Agilent 6626 power supply, damage output is controlled by a microprocessor mc68705p3, I put the microprocessor from a good one and out is working , my problem is to clone or rewrite faulty processor. I not found a simple programmer to read mc68705p3 I tried beeprog but does not activate the reader botton for this processor. Matthieu's schedule page ( Motorola MC68705P3 ( 68705P3 ) eprom reader / copier / programmer )require a preprogrammed mc68705p3 so a circle can not be out. In conclusion mc68705p3 can be programmed with Beeprog but can not read the contents of the good one , I just looking for a simple programmer to read mc68705p3 or a dump for this device , please help me !
Thank you
Costas

domino11 Thu 25 August 2011 09:33

Costas,
You would need an eeprom programmer to try anything at all on this. Even if you get the programmer, the source code could be protected. This means you will not be able to easily read the contents of the micro and make a copy. There are ways to pop the protection, but they vary quite drastically from manufacturer to manufacturer. If you are not tech savy it might be somewhat difficult.


All times are GMT -6. The time now is 08:01.

Powered by vBulletin® Version 3.8.3
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.