Transformer for Power Supply

[Nitmare67]

I am having hard time finding a power transformer to my homebrew power supply. I want my power supply to idle about around 18-20 volts but no higher than 20. I tried a regular 12v transformer but it idles at around 15.8 and drops to 11.5-12 volts while keyed. The transformer was 1 kva with 100,000mfd filter, 75amps bridge rectifiers and only drawing 55amps max from it.


So any ideas where to purchase at a decent price?

Thanks

 

[linearone]

ICAManufacturing.com - Transformers

 

[Nitmare67]

I had actually found Ica but they are almost always out of the 70 amp versions. I see most transformers are 430-7101 or 7102's. Are these the correct transformers here?

 

[linearone]

those be fine.

whered you find it

 

[Nitmare67]

A friend of mine actually has 2 of them but is not aware of their output. I noticed that the part numbers match what he says he has but is unable to check them. I will have to pay for him to ship them down south to me. I believe they will be 14 volts ac out with 120 in correct?

What is the current rating on these? The amp I am building this supply to hold is a 1x4 (1446) that is rated at 55amps max draw at 14.5volts. Will 1 of these hold this box at 14 volts or should I use both transformers with 4 bridge rectifiers and parrallel the dc side of the rectifiers before the 100,000mfc cap?

 

[unit_399]

Nitmare -

I made the transformers for my supply from ones I got out of burned out microwave ovens. Cut the HV winding off and rewound using #8 ga teflon-coated wire. Rough rule of thumb is one turn per volt. I used 6 auto headlights as a load for testing. My transformers needed 14 1/2 turns. Got the #8 wire at Home Depot. It works good, and the price was right.

- 399

 

[W9WD]

I have a collection of transformers I have gathered over the years. A lot of them out of old machine tools. Some large enough that they are hard to pickup.
I also have a collection of variable transformers (variacs). By using one or more transformers you can get close to the voltage range you want. Then just take the output of the variac and feed it to the transformers and you can hit the (any) voltage you want.
Add a bridge rectifier and some smoothing caps voi-la.

 

[Armed&Dangerous]

These transformers are 100amps. Using the white and black wires on the primary
it will float between 20 to 21 volts. They're ideal for 1 X4 Toshiba amplifier.

 

[BJ radionut]

%i

www.icamanufacturing.com

 

[jtrouter]

These transformers are 100amps. Using the white and black wires on the primary
it will float between 20 to 21 volts. They're ideal for 1 X4 Toshiba amplifier.

Question, Is there ANYWHERE that i can confirm that these transformers are 100 amps? I was able to find some but would like to verify the amperage. Anyone have any links to verify?

 

[nomadradio]

From what I was told some years ago, that transformer was made to use in a UPS, or uninterruptible power supply.

And that's all they told me. No name brand, no model. I have always suspected that the current rating is, shall we say "optimistic".

Here's the only place I know to buy one.

https://www.icamanufacturing.com/shop/transformers

73

 

[ShadowDelaware]

Updates?

 

[jtrouter]

Updates?

As with most projects I have not gotten around to putting a power supply together and do some testing.
I will post results at that. Time.
Of course life does get in the way of hobbies.