Fun withTransformers

connect the output of 2 transformers in series...  12v  +  6 v. much as you would connect batteries in series.
will it burn out?  will it produce 18 v as one would expect with batteries?.........
18 volts!!  yay!   hasnt burnt out( YET)... i wont leave this unattended.

transmission of power is more efficient at high v.  
  sooooo... if i hook the output of a 10,000 v  neon transformer to 2 thin strands of wire( think magnet wire, or a single strand from stranded cable)   and input this  10,000 v into the secondary of a second identical neon transformer, will i get usable 120 v from the primary?  (attempt to run the second transformer in reverse as a stepdown)
Nope... not YET.  Suggestions?

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gmoon2 years ago

Make sure to not use "autotransformers" for these experiments, as they aren't isolated from the mains.

Also, most modern neon PS don't output at the traditional 50-60 Hz, so make certain it's really an old-school transformer... The switching version will still be providing output, but for starters you won't be able to correctly meter it with a VOM.

(Tips as much or more for anyone wanting to replicate the OP's experiments)

Of course this stuff is dangerous. Just use your good judgement and caution. Back-to-back transformers can work very well (after all, the mains current travels though several on it's way to your home). But not always if you're using them in ways they were not designed for...

verence2 years ago

For the first experiment, yes transformers can be put in series. But as we are talking AC, the phase is important. 12V + 6V can give 18V if they are in phase or the can produce 6V if they are out of phase. (That's what you get if you swap the secondary pins of one of them as Downunder35m mentioned.

For you second experiment. No. Wrong. A transformer has no dedicated input or output side. Both sides can be the input. What is important is the ratio of windings. More windings = more voltage = less current. So a "240V to 12V transformer " has a winding ration of 20:1. Seen from the "12V-side" the ratio is 1:20 if this side is used as input. So you would expect to see 10,000V * 20 = 200kV as output on the "240V-side". That's theoretical as it is far more likely that the insulation of any side can not withstand such high voltages.

Toga_Dan (author)  verence2 years ago

1st experiment.. i should clarify that i was technically using ac to dc adapters. so, the output was red and black for + and -.

2nd experiment.. yes, running a transformer " backwards" is somewhat arbitrary. yet, if it was designed and marketed to convert 120v to 10,000 v, and we know it can do so without self destructing, then the primary and secondary, forward and backwards may as well be designated by mfg intent.

1st: Okay, no problem stacking DC that way. Keep in mid that the available current is dictated by the weaker (lower current) supply.

2nd: If it was designed for 10kV - no problem. My understanding was that you used a 'common' mains to 12V transformer.

You should not play with HV ;)
Some transformer can be used both ways, like a 240V/12V transformer will give close to 240V when you feed it 12V AC on the secondary.

HV trnasformers almost always use air gaps and other measures to provide short circuit protection.

In theory you can use them the other way around too but efficiency will be down the drain.

Buy the way: With yout 6 and 12V transformers producing 18V - check what happens if you switch the output terminals on one of them (on the 12/6V side that is!)

Toga_Dan (author)  Downunder35m2 years ago

no playing with HV??? next youll b telling me not to play with fire or rattlesnakes!

Toga_Dan (author)  Downunder35m2 years ago

i had not considered air gap. but, yeah, it looked like efficiency around 0%.