Patent GB-190824634-A (GB)
Title: Improvements in Regulators for Dynamo-electric Machines.
Filed: 1908-11-16
Granted: 1910-02-16
Abstract: 24,634. Dick, Kerr, & Co., [Thury, R.]. Nov. 16. Governors for electromotors. - A distributing- valve for a fluid motor arranged to vary the position of the brushes of an electric motor is operated by a solenoid carrying a current depending upon the speed of the motor and by hand-controlled means. The brush-holder b of the motor a is connected by a rod c to the piston d of a cylinder e, the valve f of which is operated by a jointed lever g, n connected at one end to the piston d and at an intermediate point to a solenoid core k. The solenoid is provided with two windings, one of which is energized by a small dynamo l driven by a motor a, while the second is supplied from any constant source. The current from the constant source is regulated in strength and direction by means of a rheostat m. If the circuit of the constant source is broken, the brushes occupy a position along the axis of the poles, the torque is reduced to nothing and the motor, stops. When the current from the constant source is a maximum in one direction, the motor a accelerates until a speed is reached at which the dynamo l generates a current equal and opposite to the current from the constant source, thereby causing the core k to tend to return to its original position so that the motor cannot accelerate beyond a speed fixed by the strength of current from the constant source. If the current from the constant source is reversed the motor a is reversed. In the arrangement shown in Fig. 2, the winding energized by the constant source is replaced by two springs o, p the tensions of which are controlled by a lever q. When the lever q is operated, the core k and valve f are moved, thereby causing a shifting of the brushes of the motor. The current from the dynamo l energizes the winding of the core k, thereby causing the core and the motor brushes to take up a new position. The current depending upon the speed of the motor a may be taken from a pair of fixed brushes upon the commutator of the motor. Instead of the core k acting directly upon the valve f it may operate a smaller valve which governs the action of the valve f. In the arrangement shown in Fig. 3, the force exerted by the core k is reduced by replacing the valve-rod by a rotating rod t. The rod t is provided with openings 1, 2 putting a chamber v in communication with a chamber under constant pressure or with the exhaust chamber. A chamber w constantly under pressure is placed at the other end of the valve f and has a smaller sectional area than the chamber v. The play between the rod t and the valve f allows the valve to follow the rod t by the action of the compressed fluid when the rod t is moved by the core k. In the arrangement shown in Fig. 4, the rod of the piston d is connected to the lever n by means of a spring 5, which upsets the isochronism of the regulation. The spring 5 may' be replaced by a flat spring and a dash-pot. The fluid is compressed by a pump driven by the motor a. Specification No. 9130, A.D. 1890, [Abridgment Class Dynamo-electric generators &c.], is referred to.