Holy Pyramid of Power Supplies Batman!

[Michaelinpr]

Okay. Maybe you expected more because of the title, but once I stacked these up I was pretty impressed. Just 20 x Dell 2650 500 watts. I am building some 24 V rigs for some people here in PR and just received the PSU's today.

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[pctomlin]

Great Ceasar's ghost, what are you doing showing us a picture of all those power supplies, get to work, you have friends in need!



Be sure and post some pictures of the finished product.

[Michaelinpr]

Here is a pic of the simple version. Just 2 Dell 500 watt PSU's rigged to run in series and taped together. The black connection on the left is for 24V and the one in the middle is for 12V. Red one is either or.



Here is a pic of the set up we ran at our last fun fly. The case is running 2 x dell 2850 poweredgePSU's. 24V 1400watts 57 amps. running a 208b 206b 306b and an accucell 6 and not even hitting its limits or heating up. Not really loaded up in the pic but it got some good use that day.

[tshelby73]

Do you still have to isolate the ground on one of the Dell PSU's. On the HP ones you had to. Would like to know, if not it would help if i went HP or Dell.

[Michaelinpr]

You will have to on any brand from what I understand.

The PowerEdge 2850's that are in the case are a breaze. Two screws are removed and thats it.

The Poweredge 2650's that are in the pyramid are not as easy.

All I do is remove any screw that grounds the printed circuit board to the case and place a pretty thick piece of plastic between the case and the board. There are usually enough screws laft to hold things together. I then run some epoxy in the screw hole from the outside to make sure the plastic spacers do not move. Thats it.

[belcom]

it can also be done by removing the ground wire from one of the power cables, correct? would be the same thing essentially but not as clean I guess.

[badfrog]

Originally Posted by belcom

it can also be done by removing the ground wire from one of the power cables, correct? would be the same thing essentially but not as clean I guess.

correct

[pctomlin]

Hey Michael,
Looking good, you may need to install your own power generating plant at the flying field after making all those power supplies for the guys.

tshelby 73 wrote:

Do you still have to isolate the ground on one of the Dell PSU's. On the HP ones you had to. Would like to know, if not it would help if i went HP or Dell.

The only power supply that I know of (and personally own) that does not need any modification to the PSU grounds to use in series is the Dell 6650.

belcom wrote:

it can also be done by removing the ground wire from one of the power cables, correct? would be the same thing essentially but not as clean I guess.

As badfrog said also that is correct, but very unsafe. Removing the AC ground from one of the PSUs creates an electrocution hazard because the case will see 120V AC if you have a short. When you remove a 12V ground the case will only see 12V DC if you have an issue with the PSU, much safer if the case is touched.

This is the DELL 6650 PSU, it requires no ground mods to run in series.


The sticker from one of the 6650s.

[SPARKY426]

I have an old Dell tower and an Emachines tower sitting in my garage. Could I do something with the power supplies from them ?

Chris

[belcom]

Originally Posted by pctomlin

belcom wrote:

As badfrog said also that is correct, but very unsafe. Removing the AC ground from one of the PSUs creates an electrocution hazard because the case will see 120V AC if you have a short. When you remove a 12V ground the case will only see 12V DC if you have an issue with the PSU, much safer if the case is touched.

I have 2 of those HP 47amp ones. Been only using one of them so far. What is the safer way of doing it?

Although I've been looking at that Meanwell 1000w supply for a while. What I really like about it is that it's quiet. Ones I have make a ton of noise due to small fans running at high RPM to push the air.

[TaterTot]

Where are you guys getting your server power supply(s)?

[belcom]

Originally Posted by TaterTot

Where are you guys getting your server power supply(s)?

I found the HP power supplies via ebay. It was a small local shop so I picked them up for $15 each. Work perfectly but pretty loud though. I chose these because there was a write up and what needs to be done and how.

Here it is:
http://sites.google.com/site/tjinguy...projects/HP47A
http://sites.google.com/site/tjinguy...ts/diy-24v-47a

[wolfdown]

I did the series mod on a PS. After removing the ground, I made sure to wrap the entire case in duct tape. Then if the supply ever shorts it will be impossible to accidentally come in contact with it.

[badfrog]

Originally Posted by belcom

I have 2 of those HP 47amp ones. Been only using one of them so far. What is the safer way of doing it?

Although I've been looking at that Meanwell 1000w supply for a while. What I really like about it is that it's quiet. Ones I have make a ton of noise due to small fans running at high RPM to push the air.

on the HP's, remove the case... you will see a green ground wire on the inside at the plug. Remove it or at least cut it and cap it with heat shrink, you will also see that there is a ground shield around the plug itself (silver thin metal plate around the plug with a wire to the ground) remove that also!
Use a meter to test that the ground is completely removed by setting it to ohms (test the meter... it should have a reading of 1, touch the probes... should go to very close to 0) now put one probe on the ground plug of the PS and one on the case... should NOT change. if the meter drops off, you still have some grounding somewhere.

[d1esel]

This is the DELL 6650 PSU, it requires no ground mods to run in series.


The sticker from one of the 6650s.
[/QUOTE]

I use two of these in series to power my PL8. I highly recommend them. No ground issues, and the fans are either load, or temp controlled. So it is very quiet.

[007brendan]

Originally Posted by badfrog

on the HP's, remove the case... you will see a green ground wire on the inside at the plug. Remove it....

This removes ac ground, essentially the same as cutting the ground prong off the plug. It's much safer to remove dc ground and leave ac ground intact.

[Michaelinpr]

Originally Posted by 007brendan

This removes ac ground, essentially the same as cutting the ground prong off the plug. It's much safer to remove dc ground and leave ac ground intact.

+1

Isolating the DC ground is not as hard as many think. Much safer. Would you remove the ground off any of your house hold appliances? I wouldnt.


I will be posting some pics of the process for these power supplies. These are a PITA compared to others so it should serve as a good tutorial.

Power Edge 2650 500watt 41amp. This where I get them. $16.99 for 2 shipped.

http://www.ebay.com/itm/270837559949...84.m1438.l2649

[Heli Dad]

Excuse me for being stupid, but what is it with the isolated ground. I have two HP Power suppies that I use and have no problems. what problems would I have if the grounds are not isolated or how can I check for this?
Thanks in advance

[Michaelinpr]

Are you running those 2 PSU's in series for 24V?

To run in series you have to disconnect a ground on one PS so that when you connect a positive to the negative of the other PS, it doesnt short out.

For example: Plug in two identical power supplies. Both cases are grounded to DC and AC current. When you connect PS 1 + to PS 2 -, you have actually shorted out PS 1. The same as if you touched - to +.

Now that I think about it, maybe I have this all wrong. I think that is how it works. Damn. Now I am second guessing myself.

[ericcolon]

can't wait to get mine!


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