CONSTANT MARGINAL ANGLE CONTROL SYSTEM FOR AC THYRISTOR MOTOR

摘要

PURPOSE:To control an AC thyristor motor having high accuracy at the constant marginal angle by detecting the variation of a commutation superposing angle when the angle is varied by the influence of the commutation of a power source, suppressing the output of a commutation superposing angle arithmetic circuit and eliminating the influence of the commutation of the power source. CONSTITUTION:When commutation superposing angles due to the interference of power source commutation are contracted as U1', U1'' even if a commutation superposing angle signal U(t)1 detected at timing is designated by ''1'' so that the commutation superposing angle is as U1 in a load state, the signal (C) obtained via OR of power source pulses and a signal (D) obtained via AND of the signal U(t)1 become ''1'', is inputted to a monostable multivibrator and a signal (E) becomes ''1'' during T3. Even if the output of an NOR gate forcibly becomes ''0'' with the ''1'' of the signal (E) and the signal U(t)1 become ''0'', the switch is not closed, thereby preventing the output of an operational amplifier representing the commutation superposing angle thus constructed as the above U1', U1'' from being applied to the condenser.