Forums

Loading up a 36kW transformer

Started by Yzordderrex October 7, 2013
On Mon, 7 Oct 2013 08:22:29 -0700 (PDT), Yzordderrex
<powersupplyguy@netzero.net> wrote:

>I need to load up a 36kW 3 phase 240v (output) transformer to do a heat run. I looked at having some inductors wound, but that was about $4k. I've looked at custom load bank, also about $4k. I can run three electric water heaters ($250.00 each)and discharge about 90 gals an hour of hot water. The eagle glo-coils are not manufactured anymore - what a shame. I've looked at immersion heaters and also stuffing a 50 gallon drum with elements from a stove. > >So far I like the electric water heaters the best. I can load to about 27kW and make up the rest with some big wirewounds I have kicking around. but looking for any alternate methods before I go to boss with the water heater idea. > >Any ideas? > >Bob
Too bad about the Eagle heaters, have used them in the past. Toaster oven elements? Electric stove elements? I hate water and loads, but have seen water loads used. The water heater may work as long as the thermal energy is extracted from the tank. Which brings up the thought of on-demand heaters. (might be what your thinking) Cheers
Yzordderrex wrote:
> I need to load up a 36kW 3 phase 240v (output) transformer to do a > heat run. I looked at having some inductors wound, but that was > about $4k. I've looked at custom load bank, also about $4k. I can > run three electric water heaters ($250.00 each)and discharge about 90 > gals an hour of hot water. The eagle glo-coils are not manufactured > anymore - what a shame. I've looked at immersion heaters and also > stuffing a 50 gallon drum with elements from a stove. > > So far I like the electric water heaters the best. I can load to > about 27kW and make up the rest with some big wirewounds I have > kicking around. but looking for any alternate methods before I go to > boss with the water heater idea. > > Any ideas? >
If you luck out you may be able to find some 240V/10A stadium lamps on an auction site. From a closed-down stadium they are often sold in bulk for cheap. Then you could really light up the place. -- Regards, Joerg http://www.analogconsultants.com/
On Mon, 7 Oct 2013 15:52:09 -0400, "tm" <No_one_home@white-house.gov>
wrote:

> >"Yzordderrex" <powersupplyguy@netzero.net> wrote in message >news:ecd269f4-fe27-486f-91ca-9dbf88c4f492@googlegroups.com... >I need to load up a 36kW 3 phase 240v (output) transformer to do a heat run. >I looked at having some inductors wound, but that was about $4k. I've >looked at custom load bank, also about $4k. I can run three electric water >heaters ($250.00 each)and discharge about 90 gals an hour of hot water. The >eagle glo-coils are not manufactured anymore - what a shame. I've looked at >immersion heaters and also stuffing a 50 gallon drum with elements from a >stove. > >So far I like the electric water heaters the best. I can load to about 27kW >and make up the rest with some big wirewounds I have kicking around. but >looking for any alternate methods before I go to boss with the water heater >idea. > >Any ideas? > >Bob > >++++++++++++++++++++++++++++++++++++++ > > >Another way would be to use a duct heater and fan assembly. I thing any HVAC >supplier can supply what you need. I think they come in 15 kW steps. >
Nichrome heating coil wire (.25in ID preformed) is also available at about $6 a foot. Should be > double original length for heat transfer. Coming up with a safe form that doesn't bankrupt you for ceramic insulators will take some thought. RL
On 7/10/2013 11:22 PM, Yzordderrex wrote:
> I need to load up a 36kW 3 phase 240v (output) transformer to do a heat run.. I looked at having some inductors wound, but that was about $4k. I've looked at custom load bank, also about $4k. I can run three electric water heaters ($250.00 each)and discharge about 90 gals an hour of hot water. The eagle glo-coils are not manufactured anymore - what a shame. I've looked at immersion heaters and also stuffing a 50 gallon drum with elements from a stove. > > So far I like the electric water heaters the best. I can load to about 27kW and make up the rest with some big wirewounds I have kicking around. but looking for any alternate methods before I go to boss with the water heater idea. > > Any ideas? > > Bob >
Hire a lighting tower or similar load from a hire / rental company??
"Adrian Tuddenham"

> > With the secondary O/C, measure the temperature rise due to iron losses > with full primary volts and no secondary load > > Then short the secondary and apply reduced primary volts from another > transformer to measure the temperature rise due to copper losses at full > current. > > Then calculate the effect of both together.
** Cleary the smart way to do it - the temp rise in both cases should be nearly the same. The way to measure it is to note the fractional rise in primary resistance and use the tempco of copper. IOW: Internal temp rise = 256 times the fractional increase in primary R. However, temp rise and power loss are not linearly related - the combined effect will raise the temp less than the sum of the two rises. ... Phil
On Mon, 07 Oct 2013 08:22:29 -0700, Yzordderrex wrote:

> I need to load up a 36kW 3 phase 240v (output) transformer to do a heat > run. I looked at having some inductors wound, but that was about $4k. > I've looked at custom load bank, also about $4k. I can run three > electric water heaters ($250.00 each)and discharge about 90 gals an hour > of hot water. The eagle glo-coils are not manufactured anymore - what a > shame. I've looked at immersion heaters and also stuffing a 50 gallon > drum with elements from a stove. > > So far I like the electric water heaters the best. I can load to about > 27kW and make up the rest with some big wirewounds I have kicking > around. but looking for any alternate methods before I go to boss with > the water heater idea. > > Any ideas? > > Bob
The water heaters are not a bad idea. You could do the same thing in a much smaller space by skipping the big storage tanks and installing water heater elements in pipe sections with tees on the ends, arranged to self vent with a 90 GPH flow switch and contactor for low flow protection. 3 smaller elements on a 3-phase variac could be used for trim, and the whole thing could be stuffed under a bench or on a shelf when done in case you need it again.
On Mon, 07 Oct 2013 08:22:29 -0700, Yzordderrex wrote:

> I need to load up a 36kW 3 phase 240v (output) transformer to do a heat > run. I looked at having some inductors wound, but that was about $4k. > I've looked at custom load bank, also about $4k. I can run three > electric water heaters ($250.00 each)and discharge about 90 gals an hour > of hot water. The eagle glo-coils are not manufactured anymore - what a > shame. I've looked at immersion heaters and also stuffing a 50 gallon > drum with elements from a stove. > > So far I like the electric water heaters the best. I can load to about > 27kW and make up the rest with some big wirewounds I have kicking > around. but looking for any alternate methods before I go to boss with > the water heater idea. > > Any ideas? > > Bob
Depending on where you are located you can rent a load bank for about $700/week. That was for a Houston,TX location. If you are going to be running test over the next year or so then think about buying a used one, then sell it when you are done. Google will give you lots of hits with "load bank rental" -- Chisolm Republic of Texas
On 10/7/2013 11:30 PM, Phil Allison wrote:
> "Adrian Tuddenham" > >> >> With the secondary O/C, measure the temperature rise due to iron losses >> with full primary volts and no secondary load >> >> Then short the secondary and apply reduced primary volts from another >> transformer to measure the temperature rise due to copper losses at full >> current. >> >> Then calculate the effect of both together. > > > ** Cleary the smart way to do it - the temp rise in both cases should be > nearly the same. > > The way to measure it is to note the fractional rise in primary resistance > and use the tempco of copper. > > IOW: Internal temp rise = 256 times the fractional increase in primary R. > > However, temp rise and power loss are not linearly related - the combined > effect will raise the temp less than the sum of the two rises. > > > ... Phil
Even better! It provides some safety margin. I like it. John S
"Yzordderrex" <powersupplyguy@netzero.net> wrote in message 
news:ecd269f4-fe27-486f-91ca-9dbf88c4f492@googlegroups.com...
I need to load up a 36kW 3 phase 240v (output) transformer to do a heat run. 
I looked at having some inductors wound, but that was about $4k.  I've 
looked at custom load bank, also about $4k.  I can run three electric water 
heaters ($250.00 each)and discharge about 90 gals an hour of hot water.  The 
eagle glo-coils are not manufactured anymore - what a shame.  I've looked at 
immersion heaters and also stuffing a 50 gallon drum with elements from a 
stove.

So far I like the electric water heaters the best.  I can load to about 27kW 
and make up the rest with some big wirewounds I have kicking around. but 
looking for any alternate methods before I go to boss with the water heater 
idea.

Any ideas?

Bob

Well & truly in the 'don't try this at home' category,  generators in remote 
areas were, and maybe are, tested by filling a 44 gallon drum with water, 
and immersing 3 metal plates connected to the phases mounted on a wooden 
support. Power up, then add salt to the water to get the required load. 


Yzordderrex <powersupplyguy@netzero.net> wrote:
> I need to load up a 36kW 3 phase 240v (output) transformer to do a > heat run.
My electric kitchen stove says it is 11.8 kW at full load. As a bonus, you wouldn't have to do any plumbing. Hit up the used appliance store? Every HVAC shop will have some used electric furnaces kicking around. If you swear that you aren't going to install it in a house again, they might sell one to you for cheap. You do probably need to hook up the blower motor so the elements don't melt. It will also probably have time delay relays on some of the elements so the whole thing won't come on at once; this may or may not be what you want. If you have way more time than money, hit up the local junkyard and get every sealed-beam headlight you can. The high beams are usually about 65 W, so a string of 20 gets you a whopping 1.3 kW. (Tip: Don't try to wire it so both the high beam and low beam are on; this will burn out the lamp very quickly. I found this out when building a load bank this way for a much smaller DC supply.) On the other hand, this gives you control in 1.3 kW increments. :) Matt Roberds