Discussion in 'The Projects Forum' started by fuse box 490, Mar 28, 2013.

1. ### fuse box 490 Thread Starter New Member

Mar 28, 2013
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I am brand new to All About Circuits, and I must say, this is awesome. It has everything.

I am looking to build a DC Resistive Load Bank. It would need to handle 28 VDC and a full load of 360 A in 4 steps of 90A, 180A, 270A, and 360A continuous.

I have built a few simple Control Panels over the years,mainly fluid tempurature and pump controllers but this is new to me.

I'm looking for the type of resistors,(ceramic, wire wound) configuration,(one, or more resistors per load step) cooling, (how to calculate enough air flow) etc.
If anyone has had experience with the resistor setup it would be greatly appreciated.

Oct 2, 2009
16,744
5,135
That's 10kW!

3. ### fuse box 490 Thread Starter New Member

Mar 28, 2013
5
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Exactly. Not only that, but this may have to run @ 16 hrs./day for a total of 5000 hrs.

4. ### MrChips Moderator

Oct 2, 2009
16,744
5,135
Are you located close to a lake or large body of water?

5. ### #12 Expert

Nov 30, 2010
18,078
9,616
3.16 P/CFM = dt
where dt is the Fahrenheit change of the air temperature as it goes through the box of resistors.

(5) 1.5 ohm (500 watts each) in parallel = .3 ohm
mouser part number 279-TE500B1R5J
\$34.13 ea x 20 = \$682.60 (plus shipping)

for dt = 100F, CFM = 318.5

This is only one of many ways to do this.
There is also nichrome wire, light bulbs, and rheostats.
and, yes, I do 10,000 watt furnaces with 800 cfm every week.

6. ### mcgyvr AAC Fanatic!

Oct 15, 2009
5,360
1,183
fusebox who do you work for?

assuming you need it more than once..
http://www.millerwelds.com/products/accessories/banks/
I have 2 and they are excellent.. Last month I had them both running at 50V @750 Amps for about 4 hours in my test lab.. Amazing how it can heat up a 5000 sq ft warehouse area and make all your assembly people complain.."its too hot in here" blah blah blah
seriously though by the time to design/buy/build it you would have spent twice that or more. or have build something fairly "unsafe" IMO

7. ### fuse box 490 Thread Starter New Member

Mar 28, 2013
5
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Thanks a bunch mcgyvr. That will definitely get me started. I should be alright with the switching, measuring, and whatnot. Just wasnt sure with the load and cooling setup.

8. ### fuse box 490 Thread Starter New Member

Mar 28, 2013
5
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I meant #12. Thank you too mcgyvr.

I will consider all of this. There will actually be 4 of these banks. The goal is to stay way under \$8G ea. otherwise there are a few companies that sell what I need.

9. ### #12 Expert

Nov 30, 2010
18,078
9,616
That's why we have people all over the planet helping on this site. Many points of view produce many very different answers. One person goes: when kilowatts are involved, another person works that kind of stuff for their day job, another person already has what you need and only has to point you at it.

What does \$8G mean?

10. ### MrChips Moderator

Oct 2, 2009
16,744
5,135
That means \$8k in electronics lingo.

#12 likes this.
11. ### fuse box 490 Thread Starter New Member

Mar 28, 2013
5
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Actually, it's 8 thousand dollars. Thats what I found that could be bought to do what I need. My task at work is to knock the price down considerably because there will actually be (4) of them.