If the three-phase squirrel cage induction motor,remember is 4 ~ 7 times,but not absolute. But the general requirements of ac induction motor 110kw the motor starting current is no more than the rated current of 2 ~ 5 times. Motor power for more than 30 kw motor is not suitable for frequent start,because more than 30 kw motor starting current is rated current commonly 6 to 12v mini generator motor 7 times,frequent can increase the motor temperature rise,may cause burning motor.Dc motor starting current formula Ist = (Un - Ea)/Ra,n = 0 when starting the armature voltage Ea = magnetic generator an nCe Ф = 0,and Ra is constant,so the rated voltage directly add to both wholesalemotor.blogspot.com ends of the armature,current can reach 10 ~ 30 times the rated current,therefore,usually only a small power dc motor can be used directly to start,the rest are not allowed to start directly.