The specs have an asterisk on the 100kw rating. But no footnotes are to be found.
Lowering Voltage to Elevator Drive
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The specs have an asterisk on the 100kw rating. But no footnotes are to be found.
I think it means 100 kw at 480, derated for 240 and 208
At 0.06 cents per KWH, I came up with about $52,000 per year to run that load bank.
Probably a good thing it blew up.
Also, 511 volts is only about 6% high. That would increase the power about 12%. But shouldn't the voltage have dropped back down to a nominal 480V, since that was the whole idea?
Probably a good thing it blew up.
Also, 511 volts is only about 6% high. That would increase the power about 12%. But shouldn't the voltage have dropped back down to a nominal 480V, since that was the whole idea?
zbang
Senior Member
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- Roughly 5346 miles from Earls Court
Could be in free air and maybe a 20% duty cycle (didn't look up the specific spec sheet).
JFletcher
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- Williamsburg, VA
I got $10 an hour to run it at $0.10 per kilowatt-hour, or $1,680 per week.
I'm guessing it blew up rather quickly and may have consumed less than $10 worth of electricity LOL.
Infinity, what is the actual use of that heater? As a space heater on steroids, I guess it would have a use, I don't see any application where using it as a load bank would be a good idea, aside from testing purposes.
I believe the diesel locomotives have large resistor banks for braking of the DC traction motors... I just don't see the application for what you have pictured.
Eta: the cables going to it, is there just one conductor per cable? What kind of connector is being used for the plug-and receptacle configuration?
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kwired
Electron manager
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- NE Nebraska
Is possible POCO was having malfunction of voltage regulation/tap changer and whenever this gets resolved you get closer to an acceptable voltage level again?
They do - duty cycle is normally very low.
Generator testing is one use for these load banks. A lot of times the connected load on a generator just isn't enough to do a good load test. Facilities usually want to test the generators when it causes the least impact - everyone is gone, computers are idle, all the lights are off, and the weather may be mild. So its easier to just connect a load bank than to go around and try to get all the building loads up and running.
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- New Jersey
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- Journeyman Electrician
That's likely, The unit had two indicator lights one for 480 volt (lit in the photo)and the other for 240 volts. There was no user selectable control for either voltage so I would guess that at 480 volts it was 100kw. The controls and fans ran off of a separate 120 volt source so the input voltage didn't matter to them.
We us big load banks for generator testing and they usually run for 8 hours at full output, although this unit was much smaller I would expect it to be able to run for hours without fail.
Russs57
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- Miami, Florida, USA
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- Maintenance Engineer
Infinity, look at the bright side. Someone else paid to prove the integrity of your work.
If only you had done a subpar job, the voltage would have sagged, and that joke of a load bank would have lived another day. Shame on you, do you feel guilty
Should I say this falls under no good deed goes unpaid?
And I complain about my idiot bosses that don’t understand basic concepts.
If only you had done a subpar job, the voltage would have sagged, and that joke of a load bank would have lived another day. Shame on you, do you feel guilty
Should I say this falls under no good deed goes unpaid?
And I complain about my idiot bosses that don’t understand basic concepts.
zbang
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- Roughly 5346 miles from Earls Court
Those are E1016 Camloks.
Re diesel locomotives- their breaking resistors are usually on the roof with whackin' huge fans underneath.
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And contrary to the earlier statement, they do play a role in braking on sustained downgrades.
The diesel engines provide enough power to climb that grade, and because of thermodynamic and practical inefficiency a comparable amount of power is rejected as waste heat through the exhaust and engine cooling. It is not to hard to accept that with big enough fans the same amount of heat can be directly rejected indefinitely during braking.
As a practical matter the individual truck (set of wheels) brakes on all the cars play a large role too!
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zbang
Senior Member
- Location
- Roughly 5346 miles from Earls Court
That's really the only role for dynamic brakes- they don't have "heat fade"* as wheel brakes do, so they're perfect for those long downhill runs. You'll never see them on the Florida East Coast (FEC) RR, but they're all over the BNSF or UP.
*or run out of air pressure
There's a nice article about dynamic brakes at
http://trn.trains.com/railroads/abcs-of-railroading/2006/05/dynamic-braking
(and this is all different from regenerative braking, which you can't do with a diesel
)It's amazing to see how fast a topic shifts
Same fans that cool the radiators.
When braking, the diesel engines are lightly loaded so it works out.
JFletcher
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- Williamsburg, VA
Infinity, look at the bright side. Someone else paid to prove the integrity of your work.
If only you had done a subpar job, the voltage would have sagged, and that joke of a load bank would have lived another day. Shame on you, do you feel guilty
Should I say this falls under no good deed goes unpaid?
And I complain about my idiot bosses that don’t understand basic concepts.
I was going to mention that earlier but ran out of time... That must be a pretty beefy elevator supply to put a hundred kilowatt dead load on there and only get 9v Drop
And you zbang. For identifying those cables
drcampbell
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- Location
- The Motor City, Michigan USA
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- Registered Professional Engineer
DC traction motors are almost obsolete.
https://www.progressrail.com/en/rollingstock/locomotives.html
Were I designing locomotives, I think I'd design the dynamic brakes for 100% duty cycle. Bad things happen if they're not available.
https://en.wikipedia.org/wiki/San_Bernardino_train_disaster
https://www.progressrail.com/en/rollingstock/locomotives.html
Were I designing locomotives, I think I'd design the dynamic brakes for 100% duty cycle. Bad things happen if they're not available.
https://en.wikipedia.org/wiki/San_Bernardino_train_disaster
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