UL transformer?
UL transformer?
(OP)
I am after a UL approved Class 2 transformer (UL 5085-3)
240 v primary
27 v out (could make do with 24v out)
200VA
please can you suggest any potential suppliers ? ( preferably in Europe)
240 v primary
27 v out (could make do with 24v out)
200VA
please can you suggest any potential suppliers ? ( preferably in Europe)





RE: UL transformer?
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RE: UL transformer?
xnuke
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RE: UL transformer?
"Will work for (the memory of) salami"
RE: UL transformer?
As for your 27V out -- if that's the full load rating, you are definitely in for a search. May I ask why 27V? I'm just curious. Common 24V transformers that size will deliver 27+V at no load.
Best to you,
Goober Dave
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RE: UL transformer?
27V ac is a bit strange I agree, it feeds into one of our bespoke PCB control boards, where, it is rectified for 24v DC.
I can only guess that the original designer wanted to bump up the output from tx to account for volt drop.
( as the cable run into the PCB is quite a few metres)
what say, if we used a Rockwell 1606 PSU, where it states it is a regulated Class 2 supply ?
( obviously we will need to modify our PCB to take in the DC directly from new PSU)
thanks in advance
RE: UL transformer?
By the way, it's the NEC that defines Class 1, 2, 3, etc... UL 5085 just specifies construction and testing methods to ensure that they meet the NEC rules.
Best to you,
Goober Dave
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RE: UL transformer?
thanks
so it still must be less than 100VA?
( even if it is a regulated secondary output )
Link
RE: UL transformer?
The advantage of Class 2 circuits is that in most circumstances, stuff on the downstream side of a Class 2 power supply is not subject to investigation by UL or even an AHJ (unless the AHJ decides to).
Best to you,
Goober Dave
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RE: UL transformer?
thanks, you have been very helpful, and I now fully understand
looks like in our case will be subject to full down stream testing, do not think we can get our control cicrcuit
below or equal to 100VA
RE: UL transformer?
Best to you,
Goober Dave
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RE: UL transformer?
If you have large consumers in the controls and a higher voltage level available, use the higher voltage for them and use interposing relays in the controls. Costs more in components, but gets around the limitations, which can end up costing less in the long run.
For example if you have contactors switching 230V power, but we're going to use 24V coils, use the 230V for the coils, switched by a small relay that operates at 24V. Some contactor mfrs even have clip-on interposing accessories that do this right at the contactor.
"Will work for (the memory of) salami"
RE: UL transformer?
NES-350-27
http://www.meanwell.com/search/nes-350/default.htm