500W PA amplifier with Limiter

[AndrewT]

1.7A when on no load equates to 374W for zero secondary output.
That 374W must escape as heat.

I do not believe that the 1.7A figure has been measured correctly.
It cannot be right. The transformer would be smoking, or worse, if it was dissipating 1.7Aac @ 220Vac

[hamub]

Originally Posted by AndrewT

1.7A when on no load equates to 374W for zero secondary output.
That 374W must escape as heat.

I do not believe that the 1.7A figure has been measured correctly.
It cannot be right. The transformer would be smoking, or worse, if it was dissipating 1.7Aac @ 220Vac

the figure is correct Andrew. This tx is as cold as the antarctic. I took it from a microwave oven rewound it to give 32-0-32 at the secöndary. I did not wind the primary.

[smeegle0218]

Originally Posted by AndrewT

1.7A when on no load equates to 374W for zero secondary output.
That 374W must escape as heat.

I do not believe that the 1.7A figure has been measured correctly.
It cannot be right. The transformer would be smoking, or worse, if it was dissipating 1.7Aac @ 220Vac

don't forget the P.F. (power factor). an unloaded transformer acts as an iron cored inductor, so most of the 374VA are VARs not watts. And it is the few watts that will contribute to the heating.

[apexaudio]

Originally Posted by hamub

the figure is correct Andrew. This tx is as cold as the antarctic. I took it from a microwave oven rewound it to give 32-0-32 at the secöndary. I did not wind the primary.

Andrew is right, if tx is cold after 10min. current measure is incorrect, and you can use it,
Regards

[hamub]

Originally Posted by apexaudio

Andrew is right, if tx is cold after 10min. current measure is incorrect, and you can use it,
Regards

alright thanks guys. I will check my measurements again and try to give the tx more time to see if he doesnt heat up. Maybe my analogue meter is lying. But thanks guys esp Mr Miles for an excitin thread.

[coolet]

Hi Apex,

Is this correct? You got PM

[apexaudio]

You need +/-45V on +MV/-MV. Colectors of MJE15032/MJE15033 must be connect to colectors 2SA1943/2SC5200, see post #402 in thread:
900W H-class PA Amp with Limiter
Regards

[engel dela pena]

Originally Posted by coolet

Hi Apex,

Is this correct? You got PM

hope this helps

[coolet]

@ apex tnx got it )

tnx Angel.. I'll make a new layout

so what is the +/-MV voltage? for B500

[engel dela pena]

Originally Posted by coolet

@ apex tnx got it )

tnx Angel.. I'll make a new layout

so what is the +/-MV voltage? for B500

sorry for my lines
hope this make sense
apex pls. correct me if i'm wrong