Rectifiers

Hi!

When we put load on a power transformer with half wave rectifier, the transformer vibrates badly and makes noise.
but in case of full wave rectifier (bridge rectifier) it works fine even if we put more load on it.

Can any body tell me reason of this.

Thanks

Maybe it is because the half wavve rectifier is abruptly shutting off current to the transformer where a full wave rectifier lets ot keep on going. So the windings pulse erratically in half-wave rectifier due to current flow rather than a nice sinusoidal pulsing in the full wave rectifier current flow.

Rectifier

Have you checked the rectifier diode yet? A transformer usually makes noise at a heavy overload.

There is also the possibility of wrong connection of the diode. It has to be connected in series with the load.

Connecting it parallel to the transformer it makes a dead short on the secondary winding, which causes heavy overload.

A couple of possibilities:

1 The half wave rectifier effectively causes a direct current to flow in the secondary winding of the transformer, which in turn causes the core to saturate and a high primary current to flow.

2 A fullwave rectifier draws current from the transformer in 100hz pulses, the halfwave rectifier however draws current in 50 hz pulses. The transformer core may be acoustically resonant at 50hz.

This assumes a 50 hz mains supply, if your supply is 60hz, then read 60/120 hz above.

JimB

A cheap, poorly made transformer makes noise. Everything in it is loose.