billy,
>>can I parallel the transformers
>>save the capacitors & money
Explain with a little more details, parallel the primaries, the secondaries,
what is the power in VA of the transformers you want to use and how many?
Save the capacitors, I don't think so ; you need a certain minimal amount of these
to have a good power supply.
Save money, well with a Class A, certainly not!
Regards.
Alain.
>>can I parallel the transformers
>>save the capacitors & money
Explain with a little more details, parallel the primaries, the secondaries,
what is the power in VA of the transformers you want to use and how many?
Save the capacitors, I don't think so ; you need a certain minimal amount of these
to have a good power supply.
Save money, well with a Class A, certainly not!
Regards.
Alain.
Re: Re: parallel the transformers
K-amps,
In practice, matching secondary voltage on two different transformers almost isn't possible. Small difference (in apsolute values or phase) will result in huge current between secondaries (very small internal resistance).
Billy,
if you have two transformers with 2*18/500VA you can build two monoblocks or you can parallel them, but after bridges to get 2*18V/1000VA. You can't anyway saving money on caps.
Regards
K-amps,
In practice, matching secondary voltage on two different transformers almost isn't possible. Small difference (in apsolute values or phase) will result in huge current between secondaries (very small internal resistance).
Billy,
if you have two transformers with 2*18/500VA you can build two monoblocks or you can parallel them, but after bridges to get 2*18V/1000VA. You can't anyway saving money on caps.
Regards
Re: Re: Re: parallel the transformers
However, for some types of PCB mount transformers the
manufacturers actually specify that you can parallel windings.
Probably it is because they have a very low VA rating and
thus so many turns in the windings that the potential error
is negligible.
moamps said:
However, for some types of PCB mount transformers the
manufacturers actually specify that you can parallel windings.
Probably it is because they have a very low VA rating and
thus so many turns in the windings that the potential error
is negligible.
Re: Traffo
I would think that if you measure the secondaries to make sure
there is at most a very small difference and then use a small
resistor in series with each secondary, then it will be OK. Wait
for someone else to confirm this before trying, though, I might
have overlooked something.
D3 said:
I would think that if you measure the secondaries to make sure
there is at most a very small difference and then use a small
resistor in series with each secondary, then it will be OK. Wait
for someone else to confirm this before trying, though, I might
have overlooked something.
Traffo Q
Well my traffo is biffilar.............and I need 18-0-18 @ 1000va....
my Traffo is wired with two lots 18-0-18 500va secondaries.
I had assumed that they could be parralleled ...... to give 18-0-18 1000va........single to power a single rectifier and a simple crcrc power supply.
hope this clarifys things.........
What sort of size resistor would be needed...........and what sort of wattage????
Well my traffo is biffilar.............and I need 18-0-18 @ 1000va....
my Traffo is wired with two lots 18-0-18 500va secondaries.
I had assumed that they could be parralleled ...... to give 18-0-18 1000va........single to power a single rectifier and a simple crcrc power supply.
hope this clarifys things.........
What sort of size resistor would be needed...........and what sort of wattage????
Traffo
Hi Moamps.....many thanks for the posting.........I understand the layout.................I really want to avoid using two rectifiers...if possible.....if the secondaries were linked before the rectifier.....would this cause problems.....& risk.......what are the issues.......could they be joind via a resistor????
Your advice would very much be appreciated.....................
Hi Moamps.....many thanks for the posting.........I understand the layout.................I really want to avoid using two rectifiers...if possible.....if the secondaries were linked before the rectifier.....would this cause problems.....& risk.......what are the issues.......could they be joind via a resistor????
Your advice would very much be appreciated.....................
You're saying you have two sets of windings on a single transformer. Then I see no particular reason they couldn't be paralleled. However, I'm not sure that will help you as much as you hope.
Isn't it usually the whole transformer that's VA rated, rather than the individual secondaries? After all, the primary winding and the core doesn't really care how the load is distributed across the secondaries. They just see the current and flux.
Rune
Isn't it usually the whole transformer that's VA rated, rather than the individual secondaries? After all, the primary winding and the core doesn't really care how the load is distributed across the secondaries. They just see the current and flux.
Rune
Just connect the toroids in parallel and check.
Use a 500 watt bulb (or a large 25 ohm resistor) in series with the primaries. This will limit the current to the toroids, but pass enough to check for hum etc.
If everything is ok,repeat the prcess with to a 100 or 50 watt bulb and check for current draw.
If no current draw, connect the primaries directly to the 230v AC.
Now check for abnormal heating of the toroid or audible hum.
I have used this "crude" method in joining 800Va and 1000VA toroids in parallel with no ill-effects to make 1.6kva and 2.0kva PSU's.
The more you over analyze the more you confuse yourself.
Just remember one thing, Safety first!!
K-
Use a 500 watt bulb (or a large 25 ohm resistor) in series with the primaries. This will limit the current to the toroids, but pass enough to check for hum etc.
If everything is ok,repeat the prcess with to a 100 or 50 watt bulb and check for current draw.
If no current draw, connect the primaries directly to the 230v AC.
Now check for abnormal heating of the toroid or audible hum.
I have used this "crude" method in joining 800Va and 1000VA toroids in parallel with no ill-effects to make 1.6kva and 2.0kva PSU's.
The more you over analyze the more you confuse yourself.
Just remember one thing, Safety first!!
K-
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