| 摘要 |
PURPOSE:To contrive great shock not to be transmitted to a motor and a load side even if the sudden change of the load and the momentary abnormal state of a power source are generated, by correcting the movable electrode of a liquid resistor positionally according to secondary current. CONSTITUTION:By a secondary voltage arithmetic unit 6a, arithmetic is performed on the secondary voltage FV of a motor 1, based on the output of a speed detector 5. By a secondary resistance value arithmetic unit 6b, arithmetic is performed on the resistance value FR of a liquid resistor 2, based on the position detection value of a movable electrode 2a. By a position correcting degree arithmetic unit 6c, based on the secondary voltage FV and the resistance value FR on which arithmetic is performed, the equivalent secondary current I22 of the motor 1 is found, and when the found secondary current 12 exceeds a previously set set-value, then arithmetic is performed on the position correcting degree of the movable electrode 2a on which the secondary current comes to the set value or less. |
