Transformer Question

If you go back and read my previous post, you will see that I never said to use the secondary windings. In fact I did not provide any detailed instructions. I completely agree that using two MWT's as is and connecting the secondary's is really stupid.

Dan

Transformers, absent thermal overload or soaking in salt water, are amazingly reliable. Using a dual-primary tranny as an isolation transformer will be no less reliable.

If you're really afraid of getting shocked, add a ground fault detector in series with the line input. No, use two in case one fails.

Of course, wear a bunny suit and silicone gloves, and have a buddy nearby to administer CPR.

Never eat grapes. You can aspirate one and choke to death. Best to avoid all solid food.

rowave ovens

nding of the transformer.

Sorry but to me making one transformer using parts from two transformers im plies taking the transformers apart and reassembling to make one transform er. Connecting two transformers together does not make one transformer.

If anyone is going to do this, I would not recommend grinding the welds. U sing a hacksaw is easier. If you do this you do not have to rewind the tra nsformer. You just slip the secondary winding off one core and replace it with the primaray winding from the other transformer.

Dan

A decent transformer shop confirms the count with an AC bridge gadget, direct readout.

If anyone made a 120:240 dual-primary transformer, and missed one turn, it would fry when connected to 120 volts. I've never seen that happen, over thousands of transformers.

We use 1:1 and 5:1 signal transformers in synchro/lvdt simulators, milli-degree accuracy. The turns ratios are always exact.

Required? Do you have cops or soldiers in your country who break in and inspect test benches?

How would that happen?

Use a GFD if you are afraid of 120 volts.

I am not convinced. On a 500 va transformer the amount of voltage per turn is about half a volt. So with one turn difference, I do not think it would fry the transformer. You might be right, but I am sceptical.

Dan

We have a Tek TPS2012 scope, fully isolated. It's great. You can clip a probe ground lead to anything.

Other than adding some impedance, why is that stupid?

Interesting! Thanks. Indeed I would have guessed that came from some basement Ali manufacturer. Someone at Crown needs a attitude adjustment.

Until the Italian company fires their engineers and starts sourcing from the lowest bidder with zero factory inspections or approvals.

--sp

I wish! I'd *expect* transformers to be amazingly reliable, but in my experience they aren't, even under moderately light loads.

Jeroen Belleman

I've used thousands of 120:240 power transformers, and none have failed in the field from defects of design or construction. We did have one toroid that ran into saturation, and got hot, at maximum line voltage and 50 Hz, at a UL test lab. The manufacturer had to modify the design; I think they changed the core material.

There are no doubt cheap, nasty transformers around; don't buy transformers from chop shops.

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After several minutes of that page loading a vast list of crap but still no picture I gave up.

NT

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I suspected it might be that pic :) Love it - but he should really be using some cardboard as insulation. The weld appearance suggests he's using a c oathanger as welding rod, a sure way to get a lousy weld.

NT

What is this s*it? Afro-engineering?? Seriously, fork up for a properly made tranny (unless your life has no value whatever of course, in which case, go nuts).

Thousands of power transformers....

That what we use in just about 6 hours of production, if your really want to bring in numbers. I really don't care. Your suggestion is deadly and plain wrong. I would expect you to be better than that, and know when you are wrong

Cheers

Klaus

All sorts of improbable circumstances can occasionally conspire to create a lethal situation.

WADR I think you're dishing out some very questionable advice here, John. People who need to be told how to build an isolation transformer really need to forget the whole idea and buy a decent proprietary one.

There is no fun in buying things. I kind of believe if you did not make something, it really isn't yours.

Dan