Bridge rectifier question

[Freaktron]

Is there any bridge rectifier that allows to convert 220ac into 220dc directly?

 

[audioguru]

220VAC goes from 0V to its peak of -311V through 0V to +311V then repeats.
When it is rectified then the voltage goes from 0V to +309V then repeats over and over.
If you add a filter capacitor to the rectifier then you have 309VDC.

You need a circuit to convert 309VDC to only 220VDC.

 

[Hero999]

It depends on what you want 220VDC for.

If all you want to do is power a permanent magnet motor, then use a bridge rectifier with no filter capacitor. For safety's sake you'll need to connect the motor's frame to earth, along with any other exposed metal work the encloses mains connections.

 

[Willbe]

The rms value, that is, the heating value into a resistor, of full wave rectified sine pulses is the same as the rms value of the input AC, minus a 2v total drop for the diodes.
Half wave DC is a little trickier.

 

[Hero999]

No it's not it's just half the RMS value of the input waveform minus 1V for the diode.

I forgot to say that if you're using this to power a PM motor then it's a good idea to add a reverse parallel diode to the motor to protect the bridge rectifier from the back EMF.