Abstract: In order to make possible precisely controlled and reliable operation of the rotors of a neutron chopper each rotor is to be driven by a hysteresis motor, whose rotor is in the form of a hollow cylinder. The attachment of each drive rotor to the one end of the rotor is by way of a non-magnetic disk or ring which is screwed to the lower end of the rotor or the top end thereof in accordance with the design. The drive rotor is only shrunk onto the disk or ring. The stator placed around the drive rotor is embedded within the neutron chopper housing in an electrically insulating cast material which is not affected by high vacuum and radiation.

Abstract: A device for controlling the phase of an output pulse sequence relative to an input pulse train of the same frequency comprises a multiplier receiving the pulse train from a frequency generator and emitting to a divider a rectangular waveform having a frequency m times that of the pulse train. The divider is controlled by a comparator to divide the frequency of the rectangular waveform by a factor of m.div.1, m-1, or m, depending on whether the actual phase difference between the pulse train and the sequence is less than, greater than, or equal to a predetermined phase angle, the actual phase difference being communicated to the comparator by a counter registering during each cycle of the pulse train a number of pulses proportional to the phase difference.

Abstract: A system for determining the relative angular positions of two magnetic-p rotors of respective synchronously driven (same speed) synchronous motors operated from a common frequency generator applying the driving frequency to the motors. Each rotor is provided with an optoelectronic device generating an electronic pulse for each revolution of the rotor. The pulse of one optoelectronic device is applied to the start input of a start-stop counter. The pulse from the other device is applied to the stop input of the counter and the pulse-counting input receives its signals from a frequency multiplier connected to the frequency generator.

Abstract: A device for measuring the angular position of the rotor of a synchronous motor relative to the rotating field thereof wherein the synchronous motor is driven by a frequency generator. The synchronous motor has an optoelectronic device generating a pulse for each rotation of the rotor and applied to the stop input of a counter whose start input receives from a frequency divider connected to the frequency generator and having a dividing factor equal to the number of poles of the synchronous motor. A frequency multiplier is also connected to the frequency generator and the output of the multiplier is applied to the counting-pulse input of the counter. The count registered on the counter in the interval between start and stop pulses is thus proportional to the lag of the rotor behind the rotating field.