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Author Topic: Can two 36v power supplies be used in series to get 72v?  (Read 31331 times)

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Offline Jeff_Birt

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Re: Can two 36v power supplies be used in series to get 72v?
« Reply #10 on: April 15, 2009, 03:07:51 PM »
The link to the power supplies he provided are indeed switch mode (even though he did say 'unregulated'). The same warning goes for linear power supplies as well. The common terminal can be bonded to the earth ground. The other problem you can run into is having parts (like filter caps) in the poser supply that are only rated for the voltage of one supply. Spikes and surges could cause a single supply to see a greater voltage across it than it was designed for.
Happy machining , Jeff Birt
 
Re: Can two 36v power supplies be used in series to get 72v?
« Reply #11 on: April 15, 2009, 03:22:00 PM »
You're right Mr.Birt

KL320-36 is a trademark for Keling. It is the same model as the 350 series from Meanwell.


http://www.meanwell.com/search/s-350/default.htm

Offline simpson36

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Re: Can two 36v power supplies be used in series to get 72v?
« Reply #12 on: April 15, 2009, 03:30:07 PM »
My apologies to all if I misdescribed the power supply. Not intentional . . . as I said, I'm not well versed in this stuff which is why I thought I should link to what I have.

Unfotunately I can only make an uneducated observation of things like a PC power supply which has several voltages supplied and assume there must be some simple way it does this.

I'm an engineer, but when it comes to electronic design, I'm at 'Electrons for Dummies' level, but I'm not afraid to risk asking stupid questions . . . . like . .

What is the difference between unregulated and switching? Are these mutually exclusive? Why would one be better over another.

Re: Can two 36v power supplies be used in series to get 72v?
« Reply #13 on: April 15, 2009, 03:42:56 PM »
Unregulated power supply will have a drop of voltage when it has to deliver some current, this is proportional, more current = less voltage

This is not true for a regulated power supply, the voltage will remain constant even with a rush of current

Switching power supply use high frequency square wave instead of the ordinary 60Hz sine wave to produce more current is a smaller enclosure. With high frequency, this put less stress on the component, an produce less heat.

At the output of the switching supply, the current is switch back to ordinary 60Hz sine wave but this often mean more noise for component that are affected by this.


Jeff

Offline Jeff_Birt

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Re: Can two 36v power supplies be used in series to get 72v?
« Reply #14 on: April 15, 2009, 04:00:34 PM »
Quote
KL320-36 is a trademark for Keling. It is the same model as the 350 series from Meanwell.

Does it say MeanWell on it or is it just similar to a MeanWell? I ask as I tired to get a datasheet on their power supplies months ago and was told none were available. I am somewhat dubious that they are MeanWell as if they were they should state such as MW supplies are well known for being top quality.

As to PS types. Yes an unregulated supply and a switch type supply are two different critters; kind of like a gasoline and diesel engine are different. An unregulated supply is type of linear power supply and is basically a big transformer and bridge rectifier with a few filter capacitors. It's actual output voltage depends entirely on load, the bigger the load the lower the voltage. They are simple but not real efficient. You can also have regulated linear supplies which will keep the voltage more constant but they are still inefficient.

Switch type power supplies basically work by rectifying the AC (making it DC) and then chopping up the DC (into pulsating DC) in a controlled manner. A transformer is used to convert the pulsating DC into another voltage where it is again rectified and filtered some. It is more complicated but more efficient, smaller and does not produce as much waste heat.
Happy machining , Jeff Birt
 
Re: Can two 36v power supplies be used in series to get 72v?
« Reply #15 on: April 15, 2009, 05:50:55 PM »
Jeff,  You are probably right.


I'm pretty sure too that they are all build at the same place, probably China and are distributed all over the world but each seller with put their own model number on it.

Here at home, I have several switching power supply and some can be connected parallel and some not, all depend on their basic design.

Just look at stepper driver you can buy from China, They are the same as those we can buy in North America but with different model number.

Some are cheaper, but often, they are identical.

Mr Birt, By the way, nice website

Offline Jeff_Birt

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Re: Can two 36v power supplies be used in series to get 72v?
« Reply #16 on: April 15, 2009, 06:43:51 PM »
MeanWell builds their supplies in Thailand and somewhere else I can't think of (but not China.) Nothing against Chinese made products in general but if I can't track down the OEM or find good documentation from the seller I tend to shy away (no matter where it is made.) BTW, the S-350 series from MeanWell is a very good choice for small systems. It uses a hiccup/constant current style overload protection which is ideal for this application. It is what I sell/use on smaller machines. My main point was the same as yours, you just have to be careful when trying to tie power supplies together.

Thanks for the kind words on the website.  :)

Happy machining , Jeff Birt
 
Re: Can two 36v power supplies be used in series to get 72v?
« Reply #17 on: April 15, 2009, 09:24:09 PM »
Hi Jeff.

Just took a picture of one of my switching power supply, it's made by Mean Well and we clearly see the Made in China Logo

Maybe even Thailand is now too expensive for Mean Well

Offline simpson36

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Re: Can two 36v power supplies be used in series to get 72v?
« Reply #18 on: April 16, 2009, 05:01:43 AM »
MeanWell is based in Taiwan (China).

My Keling PS does not say MeanWell anywhere on the ourside, but the Keling par numbers exactly shdow those of MenWell. THe physical appearance as well as every spec also matches exactly. All good evidence that Meanwell may manuf the PS for Keling.

The Keling mdel 320-36 that I have is working fine so far. I like the automatic thermostatically controlled fan.

Anybody have good or bad things to say about Kelings's servo motors?

Offline Jeff_Birt

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Re: Can two 36v power supplies be used in series to get 72v?
« Reply #19 on: April 16, 2009, 08:40:36 AM »
I guess I had my head up my butt concerning where MW was manufactured. I sent Keling an email to again ask about their power supplies. I may have to buy one to compare to see if it is a genuine MW or a knock-off.
Happy machining , Jeff Birt