Combining Two Transformers

[Dave]

Hi

I have two 9 amp 12 volt dc (output) transformers that I would like to use
together to provide the same voltage but at a higher amp rating. Is there a
way to do this.

Any assistance would be appreciated.

Regards
Dave

 

[Phil Allison]

Hi

I have two 9 amp 12 volt dc (output) transformers that I would like to use
together to provide the same voltage but at a higher amp rating. Is there a
way to do this.

** Is this a question on some sort of test paper OR do you *really* have
two DC supplies ??

If you do - then kindly tell us all about them.

The devil is in the detail you know.

IGNORE any fool who tries to answer your question as posted.





.......... Phil

 

[Marty Wallace]

Hi

I have two 9 amp 12 volt dc (output) transformers that I would like to use
together to provide the same voltage but at a higher amp rating. Is there a
way to do this.

Any assistance would be appreciated.

Regards
Dave

It sounds like you want to run the transformers in paralell. Yes you can do
that. With them both powered connect one output of one transformer to the
output of the other. Measure the outputs of the other two wires (AC) and if
you get zero volts then the transformers are connected in phase. if you get
double the voltage then the transformers are out of phase and you need to
swap the two outputs over. If you don't they'll go bang when you connect
them together.

Marty

 

[Dave]

there


** Is this a question on some sort of test paper OR do you *really* have
two DC supplies ??

If you do - then kindly tell us all about them.

The devil is in the detail you know.

IGNORE any fool who tries to answer your question as posted.





......... Phil

Phil

I gave up doing exams years ago. The two transformers in question came from
a garden lighting set and were given to me. I thought they may be of some
use particularly if they could be combined to provide a higher current.

They are described on the case as being Arlec 61130, Input 240V, 0.5A,
Output 12V, 9A, 108VA. I have an interest in electronics but my knowledge is
limited - hence my request.

Thanks
Dave

 

[bruce varley]

Phil

I gave up doing exams years ago. The two transformers in question came from
a garden lighting set and were given to me. I thought they may be of some
use particularly if they could be combined to provide a higher current.

They are described on the case as being Arlec 61130, Input 240V, 0.5A,
Output 12V, 9A, 108VA. I have an interest in electronics but my knowledge is
limited - hence my request.

Thanks
Dave

Dave, Transformers of the same type can often be parallelled without
problems, but you need to be aware of the potential safety hazards in doing
this. If you isolate the primary of one, then it will still be live at 240
Volt, being backfed via the other. I'm not sure what the regs say about
this, maybe someone else can advise...? You shouldn't proceed until this
has been clarified, some other poor person working on such a system
unawares could be killed..

 

[Phil Allison]

I gave up doing exams years ago.

** Good.

The two transformers in question came from
a garden lighting set and were given to me. I thought they may be of some
use particularly if they could be combined to provide a higher current.

They are described on the case as being Arlec 61130, Input 240V, 0.5A,
Output 12V, 9A, 108VA.

** What ***ever** made you decide they were DC ?????????

They can probably be wired together in parallel to give 12 volts at 18
amps AC !!!

But is 12 volts AC any good to you ??




............. Phil

 

[bruce varley]

Phil

I gave up doing exams years ago. The two transformers in question came from
a garden lighting set and were given to me. I thought they may be of some
use particularly if they could be combined to provide a higher current.

They are described on the case as being Arlec 61130, Input 240V, 0.5A,
Output 12V, 9A, 108VA. I have an interest in electronics but my knowledge is
limited - hence my request.

Thanks
Dave

On further reflection, let me be a bit blunter. It's a bloody dangerous
procedure, don't do it. There have been many near misses, and undoubtedly
fatalities as well, due to backfeed electrocutions.

 

[Ian Sutherland]

Hi Dave, Could you please tell me where I can get some dc
transformers? I'm sure they would come in handy one day.
Ian.

 

[Marty Wallace]

knowledge
Dave, Transformers of the same type can often be parallelled without
problems, but you need to be aware of the potential safety hazards in doing
this. If you isolate the primary of one, then it will still be live at 240
Volt, being backfed via the other. I'm not sure what the regs say about
this, maybe someone else can advise...? You shouldn't proceed until this
has been clarified, some other poor person working on such a system
unawares could be killed..

If you put them both in a common box so that it's obvious that they're
connected together it would be safer. Paralleling two transformers was in an
electrical test I did at the end of my apprenticeship. It's not particularly
difficult but you do have to get the phasing right.

MArty

 

[Kevin]

Is it possible to connect a few transformers to a 7Amp PS, to boost the
output amps?

 

[KLR]

Dave, Transformers of the same type can often be parallelled without
problems, but you need to be aware of the potential safety hazards in doing
this. If you isolate the primary of one, then it will still be live at 240
Volt, being backfed via the other. I'm not sure what the regs say about
this, maybe someone else can advise...? You shouldn't proceed until this
has been clarified, some other poor person working on such a system
unawares could be killed..

If the transformers are in the same enclosure - and BOTH primaries are
connected to the SAME mains power cord (permanently wired via a common
terminal block in the enclosure with the transformers etc) and both
have a common mains fuse/switch etc - then the setup should be just as
safe as with a single transformer.

I dont know about the regulations - but common sense would tend to
suggest that this method is fine. Actually on one occasion SC did
publish such a design for a car battery charger with 2 paralleled 12v
transformers (as 2 smaller ones fitted into the compact case used
where one large one of the same VA rating wouldnt) .



-------------------
If they are these "consumer" type transformers with a mains cord and
plug already fitted (as I would imagine to be the case with a garden
light transformer) - and you plan on using 2 separate mains plugs
into 2 power sockets etc - then DONT DO IT. It IS a serious safety
hazard as if one plug is plugged in and another isnt - then its pins
would be LIVE !

 

[KLR]

Hi Dave, Could you please tell me where I can get some dc
transformers? I'm sure they would come in handy one day.
Ian.

LMAO

 

[Dave]

Thanks to everyone who responded. I think I will put this idea aside until
I get more experienced in electronics.

Regards
Dave

 

[Arpit]

** Good.



** What ***ever** made you decide they were DC ?????????

It strikes me that they just may be switchmode supplies. In which case
putting them in parallel might not be such a great idea. The
switchmode supplies i tried that with when I was littler just
activated teh safety cutoff if I remember correctly.

 

[Phil Allison]

"Arpit" <

It strikes me that they just may be switchmode supplies.

** There is a very obvious difference in weight - even a novice could
not miss that.





........... Phil