A four$-$pole induction motor drives a load at $2520$ rpm$.$ This is to be accomplished by using an electronic converter to convert a $400-$V dc source into a set of three$-$phase ac voltages. Find the frequency required for the ac voltages assuming that the slip is $4$ percent. The load requires $2$hp$.$ If the dc$-$to$-$ac converter has a power efficiency of $89$ percent and the motor has a power efficiency of $80$ percent, estimate the current taken from the dc source.