Abstract: The magnet coil uses copper in the form of powder or metal chips and in bags of quartz glass fabric to bind-in any oxygen or water leaking into the enclosure in which the copper winding is located. The copper powder or chips act as absorbing medium to prevent corrosion of the copper winding.

Abstract: The circuit arrangement is provided with a pickoff in the inhibitor cancelling means which activates the cancelling means only after the lapse of a predetermined time interval during an "on" start signal for a reversal of the motor. Once activated, the cancelling means deactivates the inhibitors which are used to prevent restarts of the motor in the same direction as before a switch-off caused by a motor-load-responsive measuring means.The pickoff used may be a delay element which lengthens the first brief "on" signal after a stop for the predetermined minimum "on" time. Alternatively, the pickoff may be in the form of an integrator in which "on" signals shorter than the predetermined "on" time are summated. In this case, after summation of the discrete "on" times to the predetermined minimum "on" time, the integrator emits a signal to activate the cancelling means.