Abstract: An apparatus for providing a signal the magnitude of which indicates the loading of an AC motor. Two pairs of antiparallel-connected diodes generate two AC signals of constant amplitude and of fixed phase position relative to the motor current and the motor voltage, respectively. A load indicating signal is obtained by means of a phase comparator to which these two signals are supplied. A rectifier circuit produces a direct voltage proportional to the supply voltage of the motor, and the direct voltage is combined with the output signal of the phase comparator to compensate for variations in the output signal, which depend upon variations of the supply voltage.