Patent GB-963020-A (GB)
Title: Improvements relating to electrical motor equipment
Inventor: FRITZSCHE WILFRIED
IPC: H02P5/50
Filed: 1961-04-12
Abstract: 963,020. Automatic speed control. LICENTIA PATENT-VERWALTUNGS G.m.b.H. April 12, 1961, No. 13168/61. Heading G3R. [Also in Division H2] Motors 6, 6A, are supplied from generator 3 having a field regulator 5 which is operated by the difference between the armature voltage and a reference voltage from potentiometer 1, so determining the basic speed of the motors. The motor 6 drives a slotted disc 8 associated with lamp 9 and photo-cell 10 supplying pulses to gate 11 which also receives pulses from pulse generator 2. The gate 11 transmits trains of pulses from generator 2 to integrator 12, the time duration of each train being inversely proportional to the motor speed. The potentiometer 1 is coupled to the generator 2 so that the total number of pulses in a pulse train is the same for all basic motor speeds. A device 14 prevents pulses passing through gate 11 to the integrator 12 until the integrator clears its previous count to storage device 16, any resultant loss of pulses being automatically compensated for in the setting of reference pulse generator 13. The output from regulator RG is fed to motor field regulator 22 wherein it is compared with a reference voltage, the error voltage controlling transistor 23 in series with field winding 7. In the regulator, a switch 17 is connected to gate 11 and integrator 12 and passes a predetermined number of pulses to store 18. A reference count number is supplied to integrator 12 by generator 13 and this number is subtracted from the number received from gate 11. The difference is transmitted through filter 15 to store 16 producing a current which is compared with a current representing the basic speed, the resultant current being supplied to adder circuit 21. The store 18 also supplies a current to the circuit 21. If the motor 6 tends to deviate from the basic speed, the output of store 16 differs from zero and the regulator 22 is operated to vary the motor field excitation in a corrective sense. The motor 6 may be operated at a speed other than the basic speed by adjustment of reference pulse generator 13. The output of store 16 may control an auxiliary motor coupled to a potentiometer governing the output of circuit 21. Alternatively, the output of the store controls a field regulator directly. One of the motors may be chosen as a master motor, each of the other motors having its field controlled by the output of its own regulator together with that of the regulator of the master motor. In another embodiment, the element 5 is controlled by a regulator feeding pulses to all the regulators RG at a frequency dependent upon the armature voltage. A coincidence stage compares the pulses from the photo-cell with those from the regulator associated with the element 5 and emits a pulse to the gate 11 when the motor is running at its basic speed. The gate is opened by the pulse to transmit a constant frequency pulse output of a quartz generator to the integrator 12. Fine adjustment of the basic speed by suppressing one pulse in a certain predetermined number incident on the gate 11, Fig. 2 (not shown). Specification 901,298 is referred to.