US2419396A - Retarded shaded pole motor - Google Patents

Description

April 22, 1947. N. P. w. FRISK RETARDED SHADED POLE MOTOR Filed Feb. 16, 1944 2 Sheets-Sheet 1 III II .II I.

9 U QN k m w. Q N- NM. v4 .m an N Inventor Fro's c April 22, 1947. N. P. w. FRISK RETARDED SHADED POLE MOTOR Filed Feb. 16, 1944 2 Sheets-Sheet 2 llli.

Inventor ER 1451mm hm RETARDED SHADED POLE MOTOR Nils Pontus Wilhelm Frisk, Stockholm, Sweden, assignor to Telefonaktiebolaget L. M. Ericsson, Stockholm, Sweden, 2. company of Sweden Application February 16, 1944, Serial No. 522,685 In Sweden January 5, 1943 2 Claims.

rtlon relates to an A. ll. relay of the operating with time retardation, in 1 i magnetic fluxes, causing the driving being out of phase in relation to each .,re produced by a winding assembly coma primary winding connected to A. C. r and two secondary windings, each of h encloses a portion of the flux produced any winding and penetrating the d of relay may be employed as an inter relay between a contact device which actuated a magnitude to be controlled and instance a contactor which is actuated by the motion of the disc thereby making the desired switching. The invention is characterized by a device (for instance a cam disc) being moved by the rotation of the disc and controlling a switching device which is arranged to control the circu ts being connectible to the respective secondary windings.

The invention will now be described more particularly with reference to the accompanying drawing in which Fig. 1 is a perspective view showing the relay and the circuits connected thereto. Fig. 2(c c) are end views showing different positions of the cam disc provided on the isit oi the rotor disc and the contacts operated 1 disc. Fig. 3 shows in perspective a modithe invention whereby the shaft of the adapted to operate a rheostat. Fig.

. o views of the switching device and snowing further modification of the vhich the shaft of the rotor controls switching in of an effect in two steps. The rt core is provided with the centre limb I "*"ng the winding 2 and the side limbs 3 tee a return plate, 8 the rotor disc. The of the disc is transmitted over the gear 9 it, which is provided with a cam disc o co-operate with the spring group .ihe shaft H is assumed to actuate a tor, for instance a mercury switch. The is assumed to be connected to an A. 0.. er the terminals l6. Furthermore, the may be short circuitcd alternathe lines LI and the remote lines L2 :ahe contact 25, 22, 23 inserted in itter. When the contact between the and closed the winding 5 is short and, when a contact between 2! and 23 s winding 6 is short circuited. More The spring assembly 2 I-23 is assumed to be actuated by e. g. a thermostat which, at a given temperature, closes the contact 2l--22 and, at another temperature, closes the contact ZI-23.

The device may be employed for instance for adjusting radiator heaters, the contact 2l-22 thereby being closed by a heat sensitive device such as a thermostat when the temperature exceeds a certain value, the disc thereby turning in one direction and the shaft ll operating the radiators so that the heat supply decreases whilst, when the temperature falls below a certain value, the contact El -23 is closed, thus by the turning of the disc in opposite direction increasing the heat supply. The device operates in the following manner. When the temperature is invariable the spring 2| in the transmitter G has its middle position and the cam disc l2 2. position as shown in the centre detail of Fig. 2, in which position the spring 14 does not make contact with any of the springs I3 and (5. The disc 8 then has its zero position and is influenced only by the flux from the winding 2 which flux, upon penetrating the disc, branches symmetrically to the limbs 4 and 3, no driving torque thereby being produced. Should now, on exceeding the given temperature, for instance, the winding 5 be short-circuited by the contact 21-22, a dissymmetry follows in the fluxes which produces a clockwise operating driving torque causing the disc 8 to rotate. As soon as the disc le'aves its zero position the cam disc 12 closes the contact l3, l4 so that the winding 8 is short-circuited over resistance R. This position of the cam disc and the springs is shown in Fig. 2a. Thus, the disc will be influenced by a driving torque in the opposite direction which torque, however-the resistance R having a high value-does not suflice to overcome the first torque. Consequently, the disc 8 will turn clockwise until the shaft I l produces a decrease of the heat supply in which position the shaft II is arrested by means of a cam 3! on the disc [2 engaging a stop 33 as shown in Fig. 2a-c. When the temperature later becomes normal and the contact 2 l--22 is broken, the short-circuiting for the winding 5 is broken. The driving torque produced by the dissymmetry caused by the flux from the winding 5 thus ceases and now the disc is operated only by the torque caused by the winding 6 and operating in the opposite direction which torque is sufficient to restore the disc to its zero position, in which position the cam disc l2 breaks the contact iii-14 so that the windin 6 is no more short-circuited over resistance R, the movement of the disc thus being stopped.

The cam disc I: and springs i3| now take the position shown in Fig, 2b. Should instead the temperature have fallen below the value given, the contact 2!, 23 would have short-circuited the winding 6 and the disc would have rotated counter-clockwise until a switching operation corresponding to a rise in temperature had been performed by the shaft II, the disc 8 then would have beenrestored to its starting position which restoring in this case would be due to the shortcircuiting of the winding 5 over the contact l4, l5. This position of the cam disc and springs is shown in Fig. 2c, the movement having been stopped by means of the cam 3i engaging a stop 32. Each time a switching operation takes place the disc thus will be restored to its zero-position.

In the embodiment now described the relay as shown in Fig. la-c may be adapted in two steps to switch in a resistance comprising two parts 4|, 42, said switching being performed by means of an arm 40 connectable to three contacts 43, 44, 45, the contact position 2 |22 thereby corresponding to the starting position, the centre position of spring 2|, giving no contact, corresponds to the.

first step and the contact position 2|23 to the second step. In the starting position, e. g. the contact position 2|-22 the winding 5 is shortcircuited and thus the disc has one of its outer positions no part of the resistance being switched in, as shown in Fig. 4a. When the spring 2| during the influence of the controlling magnitude is brought to its centre position the disc, on account of the winding 6 by means of the cam disc being connected to the resistance R, is brought to its centre position where it remains. During the motion, the arm 40 engages contact 44 thereby switching in one half of the resistance 42, Fig. 411. When thereafter, during a further change in the controlling magnitude, the spring 2! makes contact with the spring 23, the winding 6 is shortcircuited and the disc turns in the same direction as before to its other outer position, the arm 40 thereby engaging the contact 45 so that the entire resistance 4l-42 is connected.

The arrangement according to the invention may also be modified in such a manner shown in Fig. 3 on the drawing that the resistance R is short-circuited and the contact springs [3-45 and 2|--22 respectively may be dispensed with, the points I3 15 being connected to the end points of one potentiometer resistance P1 and 22 and 23 to the end points of another potentiometer resistance P2, whilst the point I4 is connected to the sliding contact 25 of one potentiometer P1 and 2| to the sliding contact B of the other potentiometer P2. The sliding contact of the potentiometer P1 is controlled by the shaft H and the sliding contact of the other potentiometer P2 is controlled by the thermostat G. By a suitable gearing of the motion of the sliding contact of the potentiometer P1 in relation to the rotatable part of the relay 9. conformity of motion is obtained between the potentiometer P: and the rotatable part. If there is an unbalance between the potentiometers, the current intensity in one of the windings 5 or 6 prevails, which results in a turning of the disc 8 until the sliding contact of the potentiometer P1 has been displaced so much that the current intensities through the windings 5 and 5 are equal and the disc stops. Should the sliding contact of the potentiometer P: then change position, the balance will be disturbed anew, causing the disc again to move until balance follows.

I claim:

1. In an alternating current relay, 9. main winding adapted to be energized by alternating current, secondary coils adjacent said winding, a rotor rotatable upon short circuiting one of said secondary coils, a resistance, and means operated by rotor rotating incident to short circuiting of one of said secondary coils to connect the other secondary coil with a resistance whereby the second mentioned secondary coil exerts a driving torque on said rotor in opposition to and of less value than the rotating influence of the short circuited secondary coil.

2. In an alternating current relay, a rotor, a main winding adapted to be energized by alternating current, secondary coils operable when alternately short circuited to cause the rotor to rotate in opposite directions, a resistance, and means operated by the rotor rotating in either direction incident to short circuitin of one of said secondary coils to connect the other secondary coil with a resistance whereby the second mentioned secondary coil exerts a driving torque on said rotor in opposition to and of less value than the rotating influence of the short circuited secondary coil.

NILS PON'I'US WILHELM FRISK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,007,240 Crosthwait July 9, 1935 2,027,846 Suits Jan. 14, 1936 2,079,497 VVilhjelm May 4, 1937 2,247,165 Crise June 24, 1941 2,109,776 Johnson Mar. 1, 1938 2,134,685 Crise et a1 Nov. 1, 1938 2,123,182 Drake July 12, 1938 2,334,447 Shaw Nov. 16, 1943 FOREIGN PATENTS Number Country Date 522,130 British June 30, 1940

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