[Tig]

I have a question regarding large DC power supplies.
I plan on utilizing a couple of the Rutex R2020 Servo Drives (200V/40A). I wonder, is one better off to build a power supply based on a large rectified toroidal isolation transformer in the 5 KVA range, or buy an off the shelf solid state Power module such as the Servo Dynamics 4017-PM which delivers 170VDC at 40Amps continuous, and up to 80 Amps for 2 seconds. The PM also includes an internal shunt regulator. The SD 4017-PM is small 7.6 in x 5.2 in x 2.7 in., and weighing in at only 3.8 lbs. Other than size what are the advantages and disadvantages of each type of power supply. Is one inherently safer than the other? I look forward to your response.
Thank you.

[NC Cams]

A linear transformer (conventional or toroid) based P/S is the most rugged and inexpensive type to use/construct. A complete design analysis is found here:

http://www.elecdesign.com/Articles/A...7635/7635.html

As you go to single phase switchers or 3 phase inverters, you go up in degrees of complexity as well as cost as well as difficulty to construct and/or tune.

If Bridgeport could make a CNC mill (Eztrak) that drove 3 BIG servos and do so reliably and affordably with a transformer based P/S, it would hardly seem wise to go to the trouble of using a switcher for a DIY effort - UNLESS you can get a switcher dirt cheap and can be assured it has the "oomph" needed to do what you want it to do.

If I were building, I'd go linear - better cost vs benefit vs performance compromise.

Edit - MUCH more robust, too.....

[2muchstuff]

I'm with NC Cams on this. A linear power supply whether torroidal or E-core is the most cost effective and rugged there is. K.I.S.S.

[Tig]

Hi, is there any reason one could not use a power conditioner / noise suppression type isolation type transformer. as the bases for a DC power supply.
I came across a: Square D, # 61605-02 Output: 120/208/240 VAC -8% to +4% , 45/26/23 Amp Max, 5 kVA Total, 57-63 Hz unit. It looks to be in good condition, and the price is right. I don't think it is a toroidal type though, is there likely to be a problem from any sort of magnetic interference, or any other problems from this type of transformer.
Thanks.

[NC Cams]

If it gives you the volatage and the current you want AT 100% duty cycle, sure.

Be careful in that some such systems can't be run at full power for long periods.

DON'T put the tranformer near a monitor as it can drive it flakey. Ditto that for ANY magnetic sensitive equipment. Transformers use magnetism to step up/down voltage and you can't effectively shield magnetic fields.

[Al_The_Man]

Hi, is there any reason one could not use a power conditioner / noise suppression type isolation type transformer. as the bases for a DC power supply.

If this is a CVS type transformer, it is not a very good candidate for a power supply, they are fitted with magnetic shunts, and they have a capacitor loading a secondary winding into saturation. They run extremely hot, because of this.
You may have to take the cover off and check the innards.
5Kva is a fair sized power supply, you may have a problem getting a Toroid in that size, but a a square laminate type should be no problem, from Hammond.
Unless you get it very cheap or? I would stay away from switching supplies in this range, although they will be considerably lighter
Al.