Problems facing..

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km

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Can anyone please help me?:idea:

Why line current drawn from the mains is distorted when using a single-phase, diode bridge rectifier with dc link capacitor. Does the value of inductance and dc-link capacitor have any influence?
 
Using a bridge rectifer doesn't particularly distort the mains, using a half wave rectifier does - which is why bridge rectifiers are mandatory now in TV's and such equipment.

In the past TV's used half wave rectifiers, so if you had a complete street with all their TV's on, they were only taking the positive cycles - this caused the mains to drift negative, which was undesirable.
 
I have never heared of a DC-Link capacitor before?

However, Any kind of power supply which uses a recifier to charge a smoothing capacitor will draw a "distorted" current waveforn from the mains.

The problem is that the capacitor is only charged on the peaks of the supply waveform, so the current taken from the mains is a series of short pulses rather than a sine wave.

This can lead to heating in transformers in the mains supply system.

JimB
 
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