| 摘要 |
An electromagnetic contactor or motor controller is taught in which an energy efficient bounceless contact closing operation is utilized. An electromagnetic closing coil voltage is sensed by the contactor control system and compared against a memory menu of stored delay angles for a wide range of sensed voltages. The delay angles are applied to the conduction interval of a triac or similar gated device which is connected in series with the coil for controlling current flow therethrough. Depending upon the voltage sensed the amount of current flowing through the coil on a half cycle by half cycle basis is varied by the control system. The energy supplied to the armature of the electromagnetic closing coil is such that the armature attains a predetermined velocity during its closing operation which predetermined velocity is approximately sufficient to allow the armature to move to its final fixed closed disposition where the air gap between it and a permanent magnet is reduced to zero at a velocity of approximately zero. Generally only that much energy is supplied to the armature which is just needed to close the contacts and no more within practical limits.
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