| 摘要 |
<p>A voltage and/or frequency signal corresp. to motor current or speed is monitored and compared with threshold values to determine whether the motor is running normally or not. If the motor is running abnormally, it is then repeatedly switched off and on until the normal condition is restored. The motor is pref. switched on and off a set number of times, and the presence of a fault determined after a set switch-on time. USE/ADVANTAGE - E.g. fan motors in vehicle air conditioning system. Gives high reliability of steady running.</p> |
