Harmonics?

I have made a normal linear power supply using bridge rectifier, capacitor....Its i/p 240vac 50hz & o/p 220Vdc & load it up to 6A.
I have seen the input current waveform at scope ,I think it is like harmonics current ?
And found that the input isolation transformer become very hot.
How to reduce or eliminate the input harmonics current produced by the non-linear diode ?

wkyong said:

I have made a normal linear power supply using bridge rectifier, capacitor....Its i/p 240vac 50hz & o/p 220Vdc & load it up to 6A.
A circuit diagram would be useful.

I have seen the input current waveform at scope
Where on the circuit did you measure.?

,I think it is like harmonics current ?
Dont follow this sentence.

And found that the input isolation transformer become very hot.
Whats the rating of the transformer and what voltage/current was at the load.?

How to reduce or eliminate the input harmonics current produced by the non-linear diode ?

Click to expand...

Hi,
To make any suggestions we must see the circuit diagram also the answers to the above questions...

wkyong said:

I have made a normal linear power supply using bridge rectifier, capacitor....Its i/p 240vac 50hz & o/p 220Vdc & load it up to 6A.
I have seen the input current waveform at scope ,I think it is like harmonics current ?
And found that the input isolation transformer become very hot.
How to reduce or eliminate the input harmonics current produced by the non-linear diode ?

Click to expand...

Use an inductor with the smoothing capacitor to form an LC filter. I don't know if having input inductors (Before either the transformer or rectifier) would help because these are to prevent you from drawing high frequency currents from the AC mains which can produce a lot of problems. Or use a bunch of capacitors and inductors to make pi-filters, T-filters, or just simple LC filters (or a series of one or more of these). Or just use a bigger capacitor.

This is perfectly normal. The current harmonics are generated because the capacitor only charges at the peak voltage.

What's the current rating of the transformer? Are you sure it's large in enough?

Just out of interest, what's the output voltage of the transformer?