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!

 

[joeblack5]

It looks like these are cast iron resistors. They are designed for short duration.

Are these modules in series or in parallel?

Maybe getting the plate heaters from a cold weather heatpump or better industrial electric heater might be a better way to go.

Are you testing in single or three phase?

Good luck
Johan

 

[loosegravel]

It looks like these are cast iron resistors. They are designed for short duration.

Are these modules in series or in parallel?

Maybe getting the plate heaters from a cold weather heatpump or better industrial electric heater might be a better way to go.

Are you testing in single or three phase?

Good luck
Johan

Thanks Johan. Yes, these are cast iron plates in series. I'm thinking that with some air flow across these plates they could sustain a load for a much longer time. I was using 120 volts single phase with one unit only and pulling from 60 - 80 amps. The amperage draw seemed to increase as the plates heated up. Using ohms law with 1.5 ohms and 240 volts that would be 160 amps. Too much for the generators that I'm working with. One thing that I haven't tried is 240 volts with the two of them in series. That would be 240 divided by 3.0 ohms = 80 amps. That's still a little too much for the 10kw units, but the larger generators may be able to handle that load. At any rate, I think that these braking resistors belong in the hands of someone who is suddenly slowing down a motor of some sort. Like you said...with no air flow short duration loads are what they're designed for. Thanks for your input!
Jeff

 

[papakb]

A load bank that's larger than you need isn't a problem but one thats smaller than you need will eventually burn out. A cooling fan will certainly help but I'd suggest ducting it outside of the shop. The load is typically only used for short periods to make sure the regulator is capable of regulating the output when it's under full load.

Unlike the RF load banks used with radios that need to terminate the output power from a transmitter to waveguides and antenna feeds when you don't want any emmissions, power banks are just used to test the regulators to make sure they're capable of meeting their specifications.

 

[loosegravel]

A load bank that's larger than you need isn't a problem but one thats smaller than you need will eventually burn out. A cooling fan will certainly help but I'd suggest ducting it outside of the shop. The load is typically only used for short periods to make sure the regulator is capable of regulating the output when it's under full load.

Unlike the RF load banks used with radios that need to terminate the output power from a transmitter to waveguides and antenna feeds when you don't want any emmissions, power banks are just used to test the regulators to make sure they're capable of meeting their specifications.

Yes sir, thank you for your input. I was referring to an over-load occurrence on the generator from using a low resistance load. Low resistance equals high current. These gen sets can be loaded up to 125% of their rated load and they will run...for a short time before faulting for over-current. While using one of these braking resistors to put a load on the 10kw generator it was in fact drawing 80 amps on 120 volts. The generator handled it for a short time before faulting for over-current. I would need to add more cast iron plates into the equation to increase the resistance which would decrease the load. Many of us just need to get back to basics and use ohm's law. It works! Thanks again.

 

[ctfjr]

If you put two of them in series that will cut the amperage draw in half. Just be careful that they are insulated from each other, and you.

 

[loosegravel]

If you put two of them in series that will cut the amperage draw in half. Just be careful that they are insulated from each other, and you.

Thanks, I eventually succumbed to the fact that the braking resistors weren’t the way to go. Then, I stumbled on a Catapillar document that was dated in 1975. It describes in detail how to use a brine tank to put a load on generators. I’ve been experimenting with that method for a while now. It works very well.

 

[serpico760]

View attachment 829764
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!

I don't suppose you still want a load bank? I have three available.

 

[FarmingSmallKubota]

I don't suppose you still want a load bank? I have three available.

What size load banks do you have

 

[G744]

An old electric water heater (filled with water, BTW) can make a good load for a smaller genset. Just leave the two H2O connections open for expansion.

They usually have two elements, and pull several kW in normal use, so one can rewire them to get different loadings.

 

[loosegravel]

I don't suppose you still want a load bank? I have three available.

Thanks for your reply to this older thread! So, as mentioned in post #7 I’ve been using a brine tank method. As much as I was hoping to build or purchase a resistive type load bank, the lost art of using a brine tank has proven to be easy, clean and so much less expensive. In the last 18 months or so I’ve now used this same 40 gallon plastic drum to load test all of the machines that have past through my hands. All of the generators that I buy at auction are the MEP-8XX series. I’ve now used this same brine tank to load test the 5kw, 10kw, 15KW, 30kw and the 60kw models. In each case with each of those models I’m able to safely and accurately load test these marvelous machines in three phase up to 125% of their rated power. A couple of things that will decrease the resistance which will increase the load are too much salt in the brine mixture and the temperature of the brine. As the machines are being load tested, the temperature of the brine mixture comes up. I have a pulley that I use to raise/lower the rods into the brine tank. I keep an eye on the gauges on the machines when I’m performing a load test and as the load increases when the brine temperature comes up I simply raise the rods up slightly to decrease the load back to where I want it. I also use my amp probe on each of the three 4awg wires that I’m using to connect the load to the machines to compare the combined load to the gauges. I know that this may sound like I’m bragging some here, but the simplicity of this seemingly lost method to load test generators is just so much easier than trying to build a load bank. However, if I had the opportunity to purchase a load bank that could be used over a broad spectrum of machines like I’ve done with the brine tank method and I could get it for a reasonable price, then I would buy it. One other interesting thing about the 40 gallon brine tank that’s worth mentioning. I can leave it outside under the cover and close to my MEP-803A that I use for my personal back-up power. The 4awg cables, the pulley and the rods are permanently left out there hanging above the brine tank as well. I connect the cables to that generator and do a load test on that unit about every other month. The cables are also long enough for me to place other machines that I want to test within the proximity. The water in the tank eventually evaporates away, but the salt stays behind. So I have to periodically add more water and stir the mixture up. And, seeing this set up out there always sparks a conversation with my family and friends when they see this apparatus! Thanks for reading!

 

[loosegravel]

Thanks for your reply to this older thread! So, as mentioned in post #7 I’ve been using a brine tank method. As much as I was hoping to build or purchase a resistive type load bank, the lost art of using a brine tank has proven to be easy, clean and so much less expensive. In the last 18 months or so I’ve now used this same 40 gallon plastic drum to load test all of the machines that have past through my hands. All of the generators that I buy at auction are the MEP-8XX series. I’ve now used this same brine tank to load test the 5kw, 10kw, 15KW, 30kw and the 60kw models. In each case with each of those models I’m able to safely and accurately load test these marvelous machines in three phase up to 125% of their rated power. A couple of things that will decrease the resistance which will increase the load are too much salt in the brine mixture and the temperature of the brine. As the machines are being load tested, the temperature of the brine mixture comes up. I have a pulley that I use to raise/lower the rods into the brine tank. I keep an eye on the gauges on the machines when I’m performing a load test and as the load increases when the brine temperature comes up I simply raise the rods up slightly to decrease the load back to where I want it. I also use my amp probe on each of the three 4awg wires that I’m using to connect the load to the machines to compare the combined load to the gauges. I know that this may sound like I’m bragging some here, but the simplicity of this seemingly lost method to load test generators is just so much easier than trying to build a load bank. However, if I had the opportunity to purchase a load bank that could be used over a broad spectrum of machines like I’ve done with the brine tank method and I could get it for a reasonable price, then I would buy it. One other interesting thing about the 40 gallon brine tank that’s worth mentioning. I can leave it outside under the cover and close to my MEP-803A that I use for my personal back-up power. The 4awg cables, the pulley and the rods are permanently left out there hanging above the brine tank as well. I connect the cables to that generator and do a load test on that unit about every other month. The cables are also long enough for me to place other machines that I want to test within the proximity. The water in the tank eventually evaporates away, but the salt stays behind. So I have to periodically add more water and stir the mixture up. And, seeing this set up out there always sparks a conversation with my family and friends when they see this apparatus! Thanks for reading!

Pictures are always worth a thousand words! Sorry for the long post, and you’re welcome if it was your bed time and I put you to sleep!