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.

 

That's 10kW!

 

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

 

Are you located close to a lake or large body of water?

 

R=.311111 ohm per load
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.

 

fusebox who do you work for?

assuming you need it more than once..
Buy the "welding power load bank" #902804
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

 

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.

 

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.

 

Just wasn't sure with the load and cooling setup.

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?

 

That means $8k in electronics lingo.

 

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.

 

fusebox who do you work for?

assuming you need it more than once..
Buy the "welding power load bank" #902804
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

Super late to the party here... just saying I am dang Jealous you have 2!! Let me know if one ever needs a good new home, I am a field tech without a load bank and it hurts. LOL

 

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.

Back in 1980s I was doing automotive electrical, I used car headlights for a load. Two lamps in series will do 28V. Do not use the LED bulbs. The problems are the heat, light and the resistance of the bulbs changes with voltage. Being in a building with 1000s of bulbs made the choice easy.

I have banks of 1000W wire wound resistors.

28 VDC .................... 90A,

28VDC 90A 2500 watts I could parallel three 1000W resistors. At digikey.com this type of resistor is about $500 each. The surplus store I normally get them from is closed now. [sad face]


Here is a 2000W resistor. It needs to bolt to a large piece of Al.

 

Digi.com
1000W 1 ohm resistor for $88.27 for one. At 100 they are $52.27.
Each resistor will pull 28 amps. Three in parallel will be 84A. Close to the 90 you want. Add a small resistor to pull the 6A needed to get to 90A.
Next, we need to talk about how to cool it off. I can send pictures of how I do it.

 

Uh... the TS asked the question more than 13 years ago and hasn't been seen is just shy of that. Let's let this one rest.