I am looking for people that are able to wind high voltage high current transformers for my GU-46 project.
Is there anybody here that knows how to build power trannies, output trannies and chokes for high voltage and high current (combined) applications?
I am looking for the following SE Output trannies (options):
2.5k primary, 4 + 8R secondary, 1200V+ at 0.7A, 20Hz-25kHz frequency range, 170-180W
5k primary, 2 + 4R secondary, 1200V+ at 0.35A, 20Hz-25kHz frequency range, 85W (2 OPTs primary used in parallel, secondary series)
7.5k primary, 1.3 + 2.6R secondary, 1200V+ at 0.24A, 20Hz-25kHz frequency range, 60W (3 OPTs primary used in parallel, secondary series)
Additionally I need Power Transformers covering the following requirements
- primary 240V (!)
the following secondary voltages are required
- 2X 470-0-470V at 0.8A (approx voltage)
- 2x 170-0-170V at 0.3A
- 2x 3.15-0-3.15V at 3A
- 2x 5.1-0-5.1V at 20A (!)
The Power Transformer does not need to be in one core.
And chokes
4x 10H/450mA at 700V
2x 5-10H/700mA at 1200V
All transformers should have enough safety margin to allow safe use also at fluctuations in voltage and amperes and over longtime runs.
Feedbacks and proposals are very welcome.
Thomas
Is there anybody here that knows how to build power trannies, output trannies and chokes for high voltage and high current (combined) applications?
I am looking for the following SE Output trannies (options):
2.5k primary, 4 + 8R secondary, 1200V+ at 0.7A, 20Hz-25kHz frequency range, 170-180W
5k primary, 2 + 4R secondary, 1200V+ at 0.35A, 20Hz-25kHz frequency range, 85W (2 OPTs primary used in parallel, secondary series)
7.5k primary, 1.3 + 2.6R secondary, 1200V+ at 0.24A, 20Hz-25kHz frequency range, 60W (3 OPTs primary used in parallel, secondary series)
Additionally I need Power Transformers covering the following requirements
- primary 240V (!)
the following secondary voltages are required
- 2X 470-0-470V at 0.8A (approx voltage)
- 2x 170-0-170V at 0.3A
- 2x 3.15-0-3.15V at 3A
- 2x 5.1-0-5.1V at 20A (!)
The Power Transformer does not need to be in one core.
And chokes
4x 10H/450mA at 700V
2x 5-10H/700mA at 1200V
All transformers should have enough safety margin to allow safe use also at fluctuations in voltage and amperes and over longtime runs.
Feedbacks and proposals are very welcome.
Thomas
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Thomas, you indicate a 1200V OPT - are you going to specify a working voltage and a hipot level, or is the winder responsible for specifying ?
Are you going to want protective shields between primaries and secondaries, or require a basic or supplementary or reinforced level of insulation rather than just functional level, given that speaker terminals could well be touched as the voltage may not be deemed high enough to require IP2x type connectors such as Speakon ?
Are you going to want protective shields between primaries and secondaries, or require a basic or supplementary or reinforced level of insulation rather than just functional level, given that speaker terminals could well be touched as the voltage may not be deemed high enough to require IP2x type connectors such as Speakon ?
Hi trobbins,
good points.
The 1200V is intended to be the working voltage, not a high pot voltage.
I expect a professional transformer builder to build safe transformers, including shields between the layers and the primaries and secondaries using eg. Teflon.
Given the voltages in the OPT,s, speaker connections must clearly be shielded against crossflow of B+ or anode voltage.
Do you think this must be specified additionally (even if it should be state of the art?)?
I am usually using chinch connectors for the speakers in my amps.
good points.
The 1200V is intended to be the working voltage, not a high pot voltage.
I expect a professional transformer builder to build safe transformers, including shields between the layers and the primaries and secondaries using eg. Teflon.
Given the voltages in the OPT,s, speaker connections must clearly be shielded against crossflow of B+ or anode voltage.
Do you think this must be specified additionally (even if it should be state of the art?)?
I am usually using chinch connectors for the speakers in my amps.
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If using 8 ohm, then the peak voltage is unlikely to be considered hazardous if grounded at the amp.
There is no one 'safe' method of construction. You shouldn't abrogate responsibility for safety, which is generally why standards compliance is an easy way out - the standard does all the hard work. Given we are in diy land, standards compliance may not be a concern for you. OPT's also aren't aimed at providing mains isolation, as per a PT, but mains isolation related standards do provide a good benchmark for standard checks such as creepage, clearance, solid insulation, testing regime, and working voltage.
Just my 2 cents worth
There is no one 'safe' method of construction. You shouldn't abrogate responsibility for safety, which is generally why standards compliance is an easy way out - the standard does all the hard work. Given we are in diy land, standards compliance may not be a concern for you. OPT's also aren't aimed at providing mains isolation, as per a PT, but mains isolation related standards do provide a good benchmark for standard checks such as creepage, clearance, solid insulation, testing regime, and working voltage.
Just my 2 cents worth
You could try to ask Welter transfomatoren I Germany if they can make a high voltage OT for your project.
I am very happy with the OT's for my KT150 mono blocks and also for the 300B.
They make a special SE OT for the 6C33 tube......and they are not expensive.
You can probably write to them in German language
Welter Audio Electronic Seit 1975
I am very happy with the OT's for my KT150 mono blocks and also for the 300B.
They make a special SE OT for the 6C33 tube......and they are not expensive.
You can probably write to them in German language
Welter Audio Electronic Seit 1975
It seems they only answer technical question by phone (not by mail).
Welter Audio Electronic Seit 1975
Welter Audio Electronic Seit 1975
Regarding the spec you have mentioned while the first, 2k5 ohm, is reasonable the other two haven't a logic.
The reason are different, first of all is related to the parasitic.
About the power, I suggest that the filaments must have a very good toroid and leave the HT alone in their own nucleus.
In this way you subtract about 100 watt to the nucleus and it will became lees hot so the efficcency is better
Walter
The reason are different, first of all is related to the parasitic.
About the power, I suggest that the filaments must have a very good toroid and leave the HT alone in their own nucleus.
In this way you subtract about 100 watt to the nucleus and it will became lees hot so the efficcency is better
Walter
Hi Walter, yes, you are right. The OPT paralleling is just an option when nothing works out on the large scale OPTs.
I ordered toroid power transformers, there are two large HT trannies, two trannies for the DC filaments of the GU-46 and one for the bias voltage and the 6.3V heaters, as well as 4 5V trannies for the rectifier tubes.
I ordered toroid power transformers, there are two large HT trannies, two trannies for the DC filaments of the GU-46 and one for the bias voltage and the 6.3V heaters, as well as 4 5V trannies for the rectifier tubes.
I'm not surprised.
2k5:8 SE, 700mA static current, 180W is horrible transformer.
Do you have forklift?
More than 670V RMS primary voltage, thus 1.9kV sweep, 0.75..1mm teflon (more than 4kV) insulation between primary and secondary layers, almost 6kg copper wire, enormous -20..30kg?- core, brutal gap.....
It's a welding apparat.
Is worth it?
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