3 phase rectifier

[govender1]

My question relates to phase failure and how the rectifier operates. Lets take a situation where a three phase rectifier is feeding a load at (3kV dc)(traction motor)and suddenly the rectifier looses one of its input phases. What happens to the output of the rectifier?
Does the rectifier continue supplying the load or does it switch off.

 

[Modula2]

In cases where the supply is actually single phase, VFD's have been used to supply three phase motors. So, without being an expert, I think it may depend on the rectifier manufacture or capability of the rectifier and the increased loading on the rectifier remaining phases if output power is maintained.

 

[moturcu]

Besides more ripple at the output voltage, you will see significant drop at the power output of the rectifier. If the motor and its loads force rectifier to go out of this new power capability zone, then you may start to see overcurrent failures on both rectifier and motor side.

 

[SidiropoulosM]

Visit:

http://www.mathworks.fr/access/helpdesk_r12p1/help/toolbox/powersys/stud_c35.shtml#21666

 

[bradman]

Concur with moturcu, Unless the rectifier is fused appropietly, the current will rise as long as the load demands, usually resulting in on of the xfmr's on the rectifier burning open. regards, Brad

 

[Skogsgurra]

If there is no protection against phase loss or asymmetry, the rectifier will continue deliver (reduced) power to the load. The increased ripple will do ugly things to the traction motor - usually the commutator and the brushes will take a lot of beating.