Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: kagliostro on January 23, 2013, 08:47:41 am

Title: Boost & buck a toroidal transformer ???
Post by: kagliostro on January 23, 2013, 08:47:41 am

Assuming we have a toroidal transformer with a 100v secondary winding

Then we wrap (by hand  :icon_biggrin:) a certain number of turns of wire on it and we measure at the ends of this additional winding 30v

Connecting this added winding in series with the original winding we will have 130v or 70v depending on the phase of the windings we connect together

The question is, is this a cheap but feasible way to bost or book a toroidal transformer ?

I don't know why but I'm thinking that is possible for a bost, but I'm not sure at the same level for a buck action

Many thanks for any advice

K

Title: Re: Boost & buck a toroidal transformer ???
Post by: PRR on January 24, 2013, 06:03:53 pm

Yes.

It is likely to be nearer 0.1V per turn, so any large change of voltage will be a LOT of turns.

Title: Re: Boost & buck a toroidal transformer ???
Post by: DummyLoad on January 24, 2013, 06:13:21 pm

Yes.  It is likely to be nearer 0.1V per turn, so any large change of voltage will be a LOT of turns.

depends on core size, no?

--DL

http://www.toroid.com/standard_transformers/transformer_kits/transformer_kits.htm (http://www.toroid.com/standard_transformers/transformer_kits/transformer_kits.htm)

Title: Re: Boost & buck a toroidal transformer ???
Post by: kagliostro on January 24, 2013, 06:15:18 pm

Thanks PRR

Quote

Yes.

That is for boost & buck or only for boost ?

Thanks

K

p.s.: I posted the same time with you DL, interesting link Thanks

Title: Re: Boost & buck a toroidal transformer ???
Post by: HotBluePlates on January 24, 2013, 08:02:55 pm

You wind the new coil on the toroid. You will connect one end of the new coil to one end of the original winding.

It will either be boost or buck. If you take that same end of the new coil and connect it instead to the other end of the original winding, it will be the opposite of what you got the first time.

Title: Re: Boost & buck a toroidal transformer ???
Post by: kagliostro on January 25, 2013, 02:01:34 am

Hi

Quote

HotBluePlates

I didn't explain me in a good way

I know what you are saying

I know that adding turns and using it as boost is feasible, the voltage will rise the available current will be the VA of the transformer / the new voltage

My question is:

is safe to use the added turns as buck winding or the transformer will become hot and subject to damage ?

K

Title: Re: Boost & buck a toroidal transformer ???
Post by: HotBluePlates on January 25, 2013, 11:35:02 pm

It will be safe. If it works in boost mode, it will work in buck mode.

Title: Re: Boost & buck a toroidal transformer ???
Post by: kagliostro on January 26, 2013, 03:29:51 am

Many thanks HotBluePlates

Grazie

K