Abstract: The invention relates to a worm gear which is arranged directly on the head of an on-load tap changer and has a housing, a worm, and a worm wheel, wherein means for torque detection comprising at least one radio-scannable surface wave sensor, a rotor antenna and a stator antenna are provided in the interior of the worm gear.

Abstract: The invention relates to a method for monitoring an on-load tap changer according to the known “windowing technique,” wherein for synchronization, the current (I) on the diverter switch is continuously detected, the effective value (Ieff) is calculated, which in turn is differentiated. The corresponding point in time, at which the maximum or minimum of the differentiated value occurs, is evaluated to be the moment for the diverter switch leap (tLU), and produces the synchronization impulse.

Abstract: The invention relates to a method for monitoring an on-load tap changer according to the known “windowing technique,” wherein for synchronization, the current (I) on the diverter switch is continuously detected, the effective value (Ieff) is calculated, which in turn is differentiated. The corresponding point in time, at which the maximum or minimum of the differentiated value occurs, is evaluated to be the moment for the diverter switch leap (tLU), and produces the synchronization impulse.

Abstract: The invention relates to a worm gear which is arranged directly on the head of an on-load tap changer and has a housing, a worm, and a worm wheel, wherein means for torque detection comprising at least one radio-scannable surface wave sensor, a rotor antenna and a stator antenna are provided in the interior of the worm gear.

Abstract: The invention relates to a motor drive for actuating a step switch, consisting of a drive motor, a load transmission, and a control transmission. Means for detecting a torque are provided in the housing of the motor drive, said means consisting of a radio-requestable surface wave sensor, a rotor antenna, and a stator antenna.

Abstract: A method of controlling a step switch. From the measured values of current, voltage and phase angle at an electric drive motor during actuation of the step switch the individual picked-up active output is calculated. From the active output the corresponding torque at the drive motor is calculated. The torque in the step switch which is crucial for controlling is determined on the basis of the torque by using a specifically calculated transfer function. The transfer function is newly determined every time the switch is actuated, with the values of the preceding switch operation or the preceding switch operations being taken as a basis of the new calculation.