I've just acquired a toroidal control transformer from the scrap bin at work. The primary is 480/240 and the secondary is 240/120. It is rated at 3 kva and has little bit of heft to it. I cannot find and information on it from the manufacture (Talema), other than the fact that it was built in the United States. The part number on it is a custom part number for my company, so that doesn't really help. Applying 120 volts to any of the windings produces the expected voltages with minimal audible hum.
Any ideas?😀
Any ideas?😀
If u can unwind the secondary and bring out the center tap, then it may be useful for a solid state power amp. Other use is to connect it as an isolation transformer.
Gajanan Phadte
Gajanan Phadte
Are the windings center-tapped, i.e. 0-240-480 primary and 0-120-240 secondary? If so, you could put 120V mains into the 240V primary, and get 60-0-60 from the secondary. It could make a nice supply for a power amp.
Sorry, I meant POWER amp.😀
Sorry, I meant POWER amp.😀
Both sides have two separate windings. For instance, if you have 480 and need 120, you hook the primary windings in series and the secondary windings in parallel. However you could also leave the parallel windings independent, each with half of the current rating. They could also be hooked up in series which would create a center tap.
I'm liking the 60-0-60 idea.
I'm liking the 60-0-60 idea.
I use mine for 220-120 drop at the end of a 700' extension cord. I hate chainsaws, their fiddly carburators always being destroyed by this imitation gasoline, the stink of the burned oil, the vile noise, the kickback. Yet I have trees down all over my country property. I use a 120VAC Milwaukee sawzall, a 11" wrecker blade, and plug the first extension cord in the dryer outlet on my trailer. Another 120 VAC nema outlet on the transformer. Voila- works almost every time. If not, I tripped on the cord. I picked up a made in USA electric chainsaw at the charity resale shop for the bigger trees.
Last edited:
*That* deosn't exactly meet code 😀
Neither does plugging all your 10,000 Christmas lights into a big trafo to keep the !@#$^ GFCI's from tripping in the rain.
If I set my fields on fire I'll let you know.
Sawing a finger off or a slit in your leg with a chainsaw is perfectly legal and a mid-western tradition. Most of my maintenance shop friends have done it. Makes for great stories in the lunch room. I'm such so effete. Just because you need 10 fingers to play Pictures at an Exhibition doesn't mean you shouldn't cut them off like a real man.
Seriously, a 3Kw 60-ct transformer is too big for 4 ohm speakers. My PV1.3K (650 W/ch @ 4 ohm) amp has 95V rails. That thing is 55 lb, way too heavy to be worth much to bar bands. A 3k control transformer weighs nearly that by itself.
Sawing a finger off or a slit in your leg with a chainsaw is perfectly legal and a mid-western tradition. Most of my maintenance shop friends have done it. Makes for great stories in the lunch room. I'm such so effete. Just because you need 10 fingers to play Pictures at an Exhibition doesn't mean you shouldn't cut them off like a real man.
Seriously, a 3Kw 60-ct transformer is too big for 4 ohm speakers. My PV1.3K (650 W/ch @ 4 ohm) amp has 95V rails. That thing is 55 lb, way too heavy to be worth much to bar bands. A 3k control transformer weighs nearly that by itself.
Last edited:
It would make a nice isolation transformer for your hi-fi system. With 240V from your breaker box and wired as a SDS (Separately Derived System) with 120V receptacles.
See page 39:
http://www.middleatlantic.com/power.htm
See page 39:
http://www.middleatlantic.com/power.htm
Last edited:
Not if your application is hi-fi, where you are expecting to double down into 4 ohms, and again into 2 ohms. If you expect rails that stiff, it can't be too big. Most bar band amps have supplies that drop roughly in half at 2 ohms, and even tour grade drop to around 70% at full whomp unless it's PFC (and very expensive).
If you wire it with a 120V input and balanced with two 60V outputs, it only good for 1500 Volt Amps.
Balanced power is never as good a the advertisements promise. And then there are all the NEC limitations.
Balanced power is never as good a the advertisements promise. And then there are all the NEC limitations.
Use as an isolation transformer and experiment with balanced power. Just make sure you do not defeat the safety grounds of your gear if present. Use the 240V windings on primary and secondary for 1:1 or the 240V and 120V for 2:1 if you have 240V available for stepdown.
I'm using balanced power on the analog side of my system and found that hum pick up particularly in very low level circuitry was slightly reduced, not an earth shattering effect, but worthwhile enough that I have stayed with it.
I'm using balanced power on the analog side of my system and found that hum pick up particularly in very low level circuitry was slightly reduced, not an earth shattering effect, but worthwhile enough that I have stayed with it.
The VA rating would be reduced as a consequence of the current rating of the 240V primary connection which is probably around 12A, this of course only applies if the transformer were to be operated on 120V.. Note also that none of mine have center tapped secondaries, and I would not recommend grounding the center-tap that is present in this particular transformer - there may be some small advantages to leaving it floating - and not just on the safety front. (Mine all float, and are UL/CSA approved medical grade isolation transformers OK under NEC)
- Status
- Not open for further replies.