SU475716A1 - Electric drive with centrifugal speed controller - Google Patents

Description

This invention relates to devices for stabilizing the speed of an electric drive.

A motor drive with a centrifugal speed controller is known, in which a spring-loaded element movable under the action of centrifugal force interacts with its position sensor, the two-position output of which is connected to the drive control input.

In a known electric drive, the position sensor is mounted either on the same rotating base as the spring element, or on a fixed base. In the first case, the position sensor is connected to the control device through the rubbing contacts and the possibility of changing the speed setpoint without stopping the drive is eliminated. In the second case, the kinematic circuit of the sensor is complicated.

In addition, since the action of a position sensor of a known electric drive is based on a change in the distance between the operating point of the spring element and the sensor, it is usually necessary to use contact position sensors in connection with the small possible movements of the spring element and the need to accurately fix its given position The presence of a contact sensor reduces the control accuracy due to contact wear.

The purpose of the invention is to increase the reliability of the electric drive and the accuracy of speed control.

This is achieved by the fact that the spring-loaded element is movable in the angular direction, and on the common shaft with it there is an additional element equipped with position sensors with a two-position output mounted on a fixed base.

Motor control device

performed by a phase control system,

its input, which is the control input

electric drive, attached to the two-position output of these sensors.

To improve the accuracy of stabilization of speed, an additional element is provided that is spring-loaded, moving under the action of centrifugal force in the angular direction, in the opposite half direction, in which the first spring-loaded element is moving.

To increase the speed of the drive and, consequently, reduce losses, it is provided to connect the outputs of the position sensors to the input of the control device via an "I.

It is also possible to change the speed setpoint, for which the main and additional elements and their position sensors are installed in such a way that it is possible to make an adjusting change in their angular position.

FIG. 1 shows a block diagram of the proposed electric drive using inductive sensors as position sensors; in fig. 2 - schematic diagram of the electric drive with the implementation of the additional element stationary; ca fig. 3 is a block diagram with the execution of an additional element spring-loaded, moving under the action of centrifugal force, and connecting position sensors to the input of the control device via an "I.

On the shaft 2 rotated by the electric motor 1, a first spring-loaded element 3 is installed, which is movable under the action of centrifugal forces, and an additional element 4, which can also be made movable spring-loaded (Fig. 3). Coils of sensors 5 and 6 are installed on the fixed base, which relate respectively to the elements of Zi4.

The outputs of the sensors 5 and 6 are connected to the input of the phase control system, which in the presented embodiments forms the trigger 7 on the transistors 8, 9 and the output amplifier 10 (in FIG. 3 through the element "AND AND").

Voltage pulses are removed from the coils of sensors 5 and 6, the frequency of which is proportional to the speed of rotation, and the change in the phase of the pulses depends on the elasticity of the spring and the square of the speed of rotation.

The number of coils of sensors 5 and 6 is selected taking into account the provision of a mode of continuous motor currents (in Fig. 3 additional coils 5 and 6).

The position of the comparison trigger 7 will depend on the position of the phase signal of the sensor 5 relative to the signal of the sensor 6 and the output of the trigger 7 will be voltage pulses with varying duty cycle from 0 to 1, which controls the amplifier 10 and thus performs phase control.

When the engine speed changes, the angle between elements 3 and 4 and, consequently, the phase shift between the pulses of the coils of the sensors 5, 6 changes under the effect of centrifugal force. When the motor shaft rotates, each of the sensors will induce e. d. from closing and opening the magnetic flux of the sensor, moreover, in each coil once per turn. If the speed of the motor 1 is less than the set one, then the pulses of the sensor 6 come second, close the transistor 8 and open the transistor 9.

When reaching or increasing above a given speed, the pulses from the sensor 5 come second, close the transistor 9 and the transistor of the amplifier 10.

The indicated nature of the change in the phase angle between the pulses of the sensors 5, 6 provides for a pulse-width control of the voltage applied to the engine, aimed at maintaining a given speed.

The stability of the rotational speed mainly depends on the stability of the spring, the stability of the geometric dimensions between the coils of the sensors and the stability of the pulse duration of the sensors at a given speed of rotation.

In the drive shown in FIG. 3, during engine acceleration and in the stabilization mode with no pulse on the logic circuit “And, the pulse from sensor 6 does not turn on the transistor of amplifier 10, thereby reducing the acceleration time and losses in the stabilization circuit. The initial position of the transistor 8 of the flip-flop 7 is determined by the selection of the connection parameters of the flip-flop.

Subject invention

Claims (4)

1- Electric drive with a centrifugal speed controller, containing a spring-loaded element, moving under the action of centrifugal force, interacting with its position sensor, two-position output which is connected to the input of the electric drive control device, characterized in that, in order to increase the reliability of the drive and control accuracy, the spring-loaded element is movable in the angular direction and an additional element mounted on a fixed base with position-mounted sensors with a two-position output connected to the input of the electric drive control device, wherein the electric drive control device is made according to the phase control system neither 2. The electric actuator according to claim 1, characterized in that, in order to improve accuracy stabilization speed, the additional element is made spring-loaded, moving under the action of centrifugal force in the angular direction opposite to the direction in which the first spring-loaded element moves. 3. The electric actuator according to claim 1, characterized in that, in order to increase the speed of the actuator, the outputs of the position sensors connected to the input of the control device through the logical element "I. 4. The electric drive according to Claims 1, 2, and 3, characterized in that the main and additional spring-loaded elements and their position sensors are installed with the possibility of an adjusting change in their angular position. + 0- 6