Parallel 60 watt electronic low voltage trany

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Dennis Alwon

Dennis Alwon

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If I took 2 - 60 watt electronic low voltage transformers (120V- 12V) and hooked them up in parallel, what would happen? Would I get 120 watts out of it???
 
141211-1052 EST

Dennis Alwon:

What is a "60 watt electronic low voltage trany"?

Is this an AC or DC output? If AC how close to a sine wave is the output?
If AC is the waveform synchronized to the input AC waveform?
If synchronized that also implies exactly the same frequency, but not necessarily no phase shift.

If AC output my guess is that paralleling can be a major problem.

.
 
After energising their primaries, connect one lead of reach secondary togather. Connect oth
er two leads to true RMS voltmeter. If zero, ok. Otherwise change connections and see if zero reading obtains
If you still do not, simply give up your attempt to parallel.
 
gar said:
141211-1052 EST

Dennis Alwon:

What is a "60 watt electronic low voltage trany"?

Is this an AC or DC output? If AC how close to a sine wave is the output?
If AC is the waveform synchronized to the input AC waveform?
If synchronized that also implies exactly the same frequency, but not necessarily no phase shift.

If AC output my guess is that paralleling can be a major problem.

.
Click to expand...

I'm inclined to agree.
In sync and in phase...........unlikely one would have thought given how the transformation gets done.
 
If these 'transformers' are actually electronic switching power supplies, then unless they have been designed for parallel operation, they will likely let out their magic smoke when operated in parallel.

You might be able to get around this by using 'or-ing' diodes to parallel them...but might have better results simply splitting your loads so that each transformer has a separate load.

-Jon
 
gar said:
141211-1052 EST

Dennis Alwon:

What is a "60 watt electronic low voltage trany"?

Is this an AC or DC output? If AC how close to a sine wave is the output?
If AC is the waveform synchronized to the input AC waveform?
If synchronized that also implies exactly the same frequency, but not necessarily no phase shift.

If AC output my guess is that paralleling can be a major problem.

.
Click to expand...

Ac input and output. This is a standard trany for low voltage lighting
 
winnie said:
If these 'transformers' are actually electronic switching power supplies, then unless they have been designed for parallel operation, they will likely let out their magic smoke when operated in parallel.

You might be able to get around this by using 'or-ing' diodes to parallel them...but might have better results simply splitting your loads so that each transformer has a separate load.

-Jon
Click to expand...
If the output is AC I don't think 'or-ing' diodes would be a solution.
 
winnie said:
If these 'transformers' are actually electronic switching power supplies, then unless they have been designed for parallel operation, they will likely let out their magic smoke when operated in parallel.

You might be able to get around this by using 'or-ing' diodes to parallel them...but might have better results simply splitting your loads so that each transformer has a separate load.

-Jon
Click to expand...

I thought this would be the case. I also thought about splitting the load but it would mean having to rewire the fixture. I will probably just get a 100 watt trany.

The reason I asked is because I have about 60 of the 60 watt tranies-- I may try it just out of curiosity sake since I paid nothing for these tranies.

I think new they probably cost all of $5-$10...
 
Dennis Alwon said:
No real smoke but the tranies are now toast. :D
Click to expand...
If they were truly identical AC magnetic transformers (identical turn count), then paralleling should be fine as long as correctly phased. But it may be more likely that they used phase controlled SCRs to provide a non sine wave 60V RMS AC.
In that case small component value differences could cause serious problems since the output waveforms would not be identical and an output circuit not expecting to be back fed would likely open smokelessly.
 
GoldDigger said:
If they were truly identical AC magnetic transformers (identical turn count), then paralleling should be fine as long as correctly phased. But it may be more likely that they used phase controlled SCRs to provide a non sine wave 60V RMS AC.
In that case small component value differences could cause serious problems since the output waveforms would not be identical and an output circuit not expecting to be back fed would likely open smokelessly.
Click to expand...


Okay so how would you correctly phase a 120V trany. Are you talking the load side as correctly phased. Of course my tranies were electronic not magnetic.
 
GoldDigger said:
If they were truly identical AC magnetic transformers (identical turn count), then paralleling should be fine as long as correctly phased. But it may be more likely that they used phase controlled SCRs to provide a non sine wave 60V RMS AC.
In that case small component value differences could cause serious problems since the output waveforms would not be identical and an output circuit not expecting to be back fed would likely open smokelessly.
Click to expand...

I don't know how exactly Denis' transformers were configured but I would guess something along the lines of a switched-mode power supply (SMPS).
The input is rectified and feeds a high frequency inverter. The high frequency allows the use of a small transformer to get from one voltage level to another then a 60Hz inverter. Given that the application is lighting the shape of waveform isn't critical and there would be no need to synchronise it with the input.

On that basis it was a fair guess that it would be pretty unlikely that the output from two independent units would be in sync or in phase.
Fizzle, fizzle, bang..........
 
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