MORSE START CIRCUIT AND CONTROL METHOD THEREFOR

PROBLEM TO BE SOLVED: To allow no large start current to flow in a motor output means by permitting the detection of zero crossing point. SOLUTION: A rectifier means 10 generates an exciting current. A mode conversion means 20 switches Morse start mode to general start mode and vice versa so as to rectify a motor output means. A model reference zero crossing generating means 30 generates a signal to detect the rotational direction of the motor. A zero crossing detecting means 40 compares a model reference zero crossing signal with an actual zero crossing signal generating during rotation of the motor so as to detect the rotational direction thereof. A phase selection means 50 selects one phase at a time when a coil of each phase of the motor is not excited. A second modulating means 60 widens/shortens the pulse width of exciting current to adjust the exciting current when the starting of motor is failed. A second modulating means 70 adjusts the power-off time interval to be supplied to the motor when the starting of motor is failed.