Sir, My name is Sreenivasan. I am doing my Engineering 2nd year. I have done a project on 3-phase rectifier using thyristors. When I give its output to a resistive load I get the expected output. But, when I give its output to a D.C Shunt Motor I am getting a problem. The problem is: An EMF is generated at output which is greater than the applied voltage (i.e If I apply 220V from output of rectifier to motor the voltage across armature is >300V)
remember that the induction in the motor will generate some back EMF energy filling in the gaps that normally would be a RMS value being read. if your thyristors are firing properly to not allow for open load gaps, you most likely are getting peak voltages.
Around 311 volts maybe?
You must remember that the DC motor will also act as a DC generator and thus holding the voltage at peak. Placing a load on the motor will most likely remove that effect to some degree.
-- http://webpages.charter.net/jamie_5"
220 vac has a peak voltage of 300 volts. 1.4 times the ac voltage.
Bob
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