identify torroidal transformer amperage

[juntmeako]

hello, i recycled a torroidal transformer from a speaker, i want to know how much amps of this transformer, olease help me identify, i will be using this to build my bench psu

[kasfamily]

Re: identify torroidal transformer amperage

Geometrical dimensions of the transformer, weight, cross-section of the wires of the primary and secondary windings ?

[keeney123]

Re: identify torroidal transformer amperage

Geometrical dimensions of the transformer, weight, cross-section of the wires of the primary and secondary windings ?

That is interesting using weight and cross-section of windings. Most likely you would not need the dimensions as you have the voltage rating of the primary and secondary. I would image only a certain cross-section of a primary and secondary can weigh that much and deliver that voltage?

[sam_sam_sam]

Re: identify torroidal transformer amperage

hello, i recycled a torroidal transformer from a speaker, i want to know how much amps of this transformer, olease help me identify, i will be using this to build my bench psu

Do you still have the device that this came out of it should have data plate on it so you can get a rough estimate of it amperage

One note I would first start by putting a rectifier diode assembly with no load on it for an hour so you have a reference point and go from there

Then I would just estimate it current by putting one amp load let it run for an hour and take it temperature and if not that warm then go to 2 amp load and keep going up as long as your transformer does not get so hot that you can not keep your hands on it

I did a quick search for audio toroidal transformer and most of them that I saw were in a amperage range of 1 to 3 amps

[juntmeako]

Re: identify torroidal transformer amperage

hi sam, i only have the transformer now, yeah i connected a bridge rectifier without caps and load, i run it like that for almost an hoir, the temps of the transformer felt like normal, not hot , jus normal temp i have no thermal scanner to exactly do temp meas, one thing i did not do is to put a load on it, anyway can you guess the amps based on its marking? BX1201

[keeney123]

Re: identify torroidal transformer amperage

hi sam, i only have the transformer now, yeah i connected a bridge rectifier without caps and load, i run it like that for almost an hoir, the temps of the transformer felt like normal, not hot , jus normal temp i have no thermal scanner to exactly do temp meas, one thing i did not do is to put a load on it, anyway can you guess the amps based on its marking? BX1201

Here is a link for you.

https://www.electricaltechnology.org...nsformers.html

[juntmeako]

Re: identify torroidal transformer amperage

thanks, btw, it has 1.5A fuse on primary winding

[keeney123]

Re: identify torroidal transformer amperage

thanks, btw, it has 1.5A fuse on primary winding

As I remember if one has say 200 volts on the primary winding at 1.5A and you drop down to say12 volts on the secondary your current will be inversely proportional to the primary. You would set up a proportion like 200/12=X/1.5 Solve for x to get current in secondary.

[juntmeako]

Re: identify torroidal transformer amperage

hmm so 230V/28V = 8V
and 8V/1.5A = 5A, so my transformer output current is upto 5A?

230V primary, 28V-0-28V secondary

[keeney123]

Re: identify torroidal transformer amperage

hmm so 230V/28V = 8V
and 8V/1.5A = 5A, so my transformer output current is upto 5A?

230V primary, 28V-0-28V secondary

Is the 28V-0-28V one winding with +28 volts, center tap 0V, and -28Volts? if it is one winding than the voltage difference is 56 volts. You would then be going from 230V to 56V. If they are separate winding then you would figure them individually. Also, remember that the fuse rating is 1.5 A so the actual current will be less. Usually a engineer will make a safety factor of 40%. The actual current could be 1.5x.6= 0.9A I believe a 1A 230 primary is a realistic supply.

[juntmeako]

Re: identify torroidal transformer amperage

its dual secondary, there are 3 wires is sencondary, blue-black-blue(28-0-28)

my transformer weighs 1.25kg, its outer diameter is 94mm, height 39mm, inner diameter is 45mm. its rough measurement

[juntmeako]

Re: identify torroidal transformer amperage

correction, its not dual secondary, its center tapped

[stj]

Re: identify torroidal transformer amperage

110VA

based on weight and outputs
using these as reference:
https://uk.rs-online.com/web/p/toroi...ormers/2238049
https://uk.rs-online.com/web/p/toroi...ormers/7581042

[keeney123]

Re: identify torroidal transformer amperage

correction, its not dual secondary, its center tapped

What I have read is that normally with a transformer when figuring out VA they use a power factor of 0.8 but, these types of transformers are more efficient for the power factor. It becomes 0.9 This can be looked upped online on how to figure it out. Basic understanding is that the primary has just so much power figuring on current and voltage. That power will be transmitted through to the secondary at a loss. Although the magnetic transference is 99% efficient i guess the power takes a hit by 10% in this case.