| 摘要 |
PURPOSE: A control apparatus and a method for protecting an electric motor are provided to control various electric motors having different rated capacity and set overcurrent, overloading, and leakage current by employing digital mode. CONSTITUTION: An MCT(Motor Current Transformer)(11) transforms driving voltage of an electric motor applied from a power source. A first A/D(Analog-to-Digital) converter(13) converts an MCT current applied from the MCT(11). A ZCT(Zero Current Transformer)(12) provides the electric motor with a driving power applied through the MCT(11) and outputs leakage current. An electric relay(20) switches the driving power. A CPU(Central Processing Unit)(15) controls the electric relay(20) to protect the electric motor. A display(19) displays various values, such as current, delay time, load current, and so on, set through a setting switch(17).
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