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  #1  
Old Wed 29 November 2006, 16:20
Bob Cole
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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.
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  #2  
Old Wed 29 November 2006, 16:41
Mike Richards
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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).
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  #3  
Old Tue 06 March 2007, 18:46
Bob Cole
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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?


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.
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  #4  
Old Tue 06 March 2007, 22:10
Mike Richards
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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.
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  #5  
Old Tue 06 March 2007, 23:10
Gerald_D
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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.
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  #6  
Old Fri 09 March 2007, 08:30
Bob Cole
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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/
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  #7  
Old Fri 09 March 2007, 08:55
Gerald_D
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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.
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  #8  
Old Sat 29 March 2008, 10:36
kalimero
Just call me: kalimero
 
buffalo
United States of America
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.
Attached Images
File Type: jpg IMG_2060lnp.jpg (29.2 KB, 457 views)
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  #9  
Old Sat 29 March 2008, 18:08
Richards
Just call me: Mike
 
South Jordan, UT
United States of America
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.)
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  #10  
Old Sun 30 March 2008, 01:00
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
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.
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  #11  
Old Sun 30 March 2008, 05:13
kalimero
Just call me: kalimero
 
buffalo
United States of America
Can I use this one :

http://search.digikey.com/scripts/Dk...name=P10025-ND
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  #12  
Old Sun 30 March 2008, 06:38
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
That one will work, but how will you attach the wires? Rather use one with screw terminals.
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  #13  
Old Sun 30 March 2008, 13:57
kalimero
Just call me: kalimero
 
buffalo
United States of America
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
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  #14  
Old Mon 31 March 2008, 00:07
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
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.
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  #15  
Old Wed 11 June 2008, 17:39
dmoore
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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
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  #16  
Old Wed 11 June 2008, 19:50
smreish
Just call me: Sean - #5, 28, 58 and others
 
Orlando, Florida
United States of America
...except the toriodal transformers we use for stepper/servo use are typically of the "unregulated" type - not regulated as you have linked.
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  #17  
Old Wed 11 June 2008, 20:35
domino11
Just call me: Heath
 
Cornwall, Ontario
Canada
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.
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  #18  
Old Thu 12 June 2008, 01:52
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
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.
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  #19  
Old Mon 22 August 2011, 05:30
costas srl
Just call me: costas
 
mures
Romania
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
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File Type: jpg Agilent HP6626A resize.jpg (14.3 KB, 268 views)
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  #20  
Old Thu 25 August 2011, 10:33
domino11
Just call me: Heath
 
Cornwall, Ontario
Canada
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.
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