"Braking resistor" used as a load bank?

[loosegravel]

I've been buying and selling the MEP generators for a couple of years now. When I "show" one to a perspective buyer I usually connect it to my shop main panel where I can turn on various different breakers to show that it's producing power. I've been looking for a load bank for a while now, and also kicking around the idea of building one. I bid on a couple of "braking resistors" that I saw on Iron Planet yesterday. Not knowing what they really were, I took a chance. Well of course I won them both. They're brand new "Gino ESE" braking resistors. The identification plates have them at 1.5 ohms, 1100 volts and 1400 amps. Of course that's way to "hot" for load testing these marvelous MEP generators. But using ohms law if I supply 208vac across something that's 1.5 ohms that comes out to a little over 138 amps or 28.5kw. That's still a little to hot for the smaller generators. But I'm wondering if I could reconfigure something like this to have individual, smaller loads and use 20 amp toggle switches to apply them? Also, there is a bolt on one end of the box that sandwiches all of these plates together. It looks like it could also be used like a "carbon pile" DC load tester, only it would be A/C instead. I'm just wondering if anyone here has any experience with using a braking resistor as a load bank. Maybe I have essentially purchased a couple of $200 boat anchors! Ahh yes, it wouldn't be the first time!

 

[Triple Jim]

You could put several of these in series, adding 1.5 ohms each time you add one. The catch is knowing how much power they can handle for some reasonable time like several minutes or an hour, or whatever amount of time you want to load the generator. I'm not familiar with them to know the answer. That one looks pretty big and healthy though. Fan cooling could help too, if needed.

 

[rickf]

You can probably find most of what you need to know here. This statement here in one of the charts is what would worry me in your application.

"The typical field of application for cast iron resistors of the GEW series are short, high-energy impulse loads."

Braking resistors | GINO AG Electrotechnical factory

Braking resistors from GINO ✅ A braking resistor reliably converts energy into heat & slows down the motor ✓ Discover different models now!

www.gino.de

 

[rickf]

Reading through that Gino site the last page has the best info and some calculations. Not going to copy and paste, you can just read it from there.

 

[loosegravel]

Thank you both for your input. I purchased (2) of these brake resistor units yesterday. They're heavy, about 300 pounds ea. So even in series I have only 3 ohms. I really need something that I can switch on and off starting with 10 ohms, 8, 6 and 4 etc. And as you've both indicated heat dissipation is a problem. Fans would be needed to cool these cast iron plates. Application...these are designed for momentary heat absorption and dissipation. How they'll behave in a long term application even with some extra air flow is anybody's guess. Well, they may be of some value to the right person. It's just a matter of me getting their attention now! Thanks again.

 

[Triple Jim]

Wow, 300 lbs! They may take a load for quite a while before they get hot! Are they made so they can be configured? Like can you unplug modules to increase the resistance, for example?

 

[loosegravel]

I wish they were. Unfortunately the cast iron plates are just stacked and bolted in series. I believe there's 12 of them. By removing any of them it effectively lowers the resistance valve, going the wrong way.

 

[glcaines]

Have you thought about contacting GINO AG in Germany and discussing with them? I know they do make load testing resistors. I would recommend trying to contact one of their technical engineers, not the sales group.