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Deckel transformer running hot?

AlfaGTA

Diamond
Joined
Dec 13, 2002
Location
Benicia California USA
So looking for some help/information from the community.
I am looking for numbers of how hot the core (lamination's) get on your Deckel 220-380 autotransformers.

Have several here at home shop, one was dropped by the previous owner, and i assumed it was damaged (windings broken loose, failed insulation etc)
It seems to run fine, voltage is stable and the same across all three legs. No unusual noises, no humming, and no real visible damage save some tears in the insulating paper on one of the coils.
Coils seem tight on the core as best i can test....

Problem is it seems to run hot on the core(not the coils). 3-4 hours of light load checked with an IR temp gun (not the most accurate) and the laminated core is running at about 175* f......

So i checked the other transformer under similar light load, seems to heat up to a similar amount. Left on overnight , just idling temp in the morning, about 175-177*f
So either this is normal, or both transformers i own have a similar problem.

Hoping i can get some of you to check your transformers....Take some temperatures of the cores after running for some time.
This is the factory Deckel setup. 15kva. 220/240- 380v three phase autotransformer.....
Does not seem to take much load, just the control turned on with the cooling fan running in the big green cabinet for a few hours.

Cheers Ross
 
The isolation transformers in my Hurcos generate alot of heat- and have fans in the transformer compartments to cool things down. I've never measured the temperature, but its noticeable. I also have two wall mounted 240 to 480 wall mounted transformers in the shop for a few machines that are 480 only. These also generate a fair amount of heat due to various losses. Here is a good article that discusses losses in transformers. Those losses essentially generate heat so.....

Even transformers that are "idling" continue to exhibit losses that generate heat.

With the cost of my PG&E electricity approaching $0.50/KWH, I'm shutting off the power to my transformers in order to save a few $$ , and also killing the power to the Hurcos when they are not being used.

Pretty sure your transformers are just being "transformers".
 
Perhaps get/find a current clamp multimeter and measure, if/where the current goes on secondary side?
130F/55°C isn't exacly worrysome but that heat/power still costs money, on the long run.
 
Ross, are the transformers marked for frequency? I think that a 50 Hz transformer operated at 60 Hz may run hot, because the core material properties are tuned to a particular frequency. But I'm not sure about this. Cheers, Bruce

PS: congrats on getting your FP3 project finished, it looks fantastic!
 
Ballen, I’m not an electrical engineer, but I think you are correct- the two 50 hz transformers I had definitely ran hotter than same size 60 hz both on 60 hz supply,
 
This looks like a competent summary:

https://www.lstransformer.com/News/can-50hz-and-60hz-transformers-be-interchangeable

Point 2 contains the following:
2. Heating and Efficiency: When a transformer designed for 50Hz is used in a 60Hz system, the higher frequency causes increased eddy current and hysteresis losses, resulting in higher temperatures and reduced efficiency. Similarly, using a 60Hz transformer on a 50Hz system can cause underutilization and overheating, potentially damaging the insulation and winding.
 
2. Heating and Efficiency: When a transformer designed for 50Hz is used in a 60Hz system, the higher frequency causes increased eddy current and hysteresis losses, resulting in higher temperatures and reduced efficiency. Similarly, using a 60Hz transformer on a 50Hz system can cause underutilization and overheating, potentially damaging the insulation and winding.
The first part makes sense - higher frequency causing more losses through hysteresis, causing more heat and less efficiency, okay.

But the second part, "underutilization" -- wtf does that have to do with anything ? if I run three amps through a 00 wire it doesn't lose efficiency through "underutilization". And why "overheating" ? from what ? with lower frequency you should have less hysteresis thus less heat produced.

I'm no electrics guy so it's possibly correct but the reasoning of the second part of that statement makes no sense. Where's JST, now that we need him ?
 
Seems a bit funny.
These transformers are all ( all that I have seen) made for 50hz.
They were the factory supplied transformers for export ( US) machines to supply the 380v needed to run the FP-NC’s
Main drive motors as well as the coolant pump were also 50 hz.
Factory did provide a different drive pulley ratio to compensate for the higher 60hz US power.
Strange that the transformers would not have been built for 60 hz.
Cheers Ross
 
Seems a bit funny.
These transformers are all ( all that I have seen) made for 50hz.
They were the factory supplied transformers for export ( US) machines to supply the 380v needed to run the FP-NC’s
Main drive motors as well as the coolant pump were also 50 hz.
Factory did provide a different drive pulley ratio to compensate for the higher 60hz US power.
Strange that the transformers would not have been built for 60 hz.
Cheers Ross

Guessing the factory knew the 50hz would work on 60hz and didn’t want to stock two different types. Esp if their market in North America was much smaller than Europe?
 








 
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