SU1525851A1 - Electric drive - Google Patents

Abstract

The invention relates to electrical engineering and can be used to control the electromechanisms of household, medical equipment. The purpose of the invention is to increase the reliability and quality of regulation. The electric drive comprises an electric motor 1 connected to a controllable valve 2, the control electrode of which through the threshold element 3, the phase-shifting circuit 4 and the capacitor 5 is connected to the coil 7 of the tachometer with core 8. The coil 7 of the tachometer is used as a contactless setting unit providing regulation and maintenance set frequency of rotation. The rotational speed control is achieved by changing the position of the coil or by moving the magnetic screen. 1 il.

Description

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The invention relates to electrical engineering, in particular to an automated electric drive.

The purpose of the invention is to increase the reliability and quality of regulation.

The drawing shows a diagram of the drive.

The electric drive contains an electric motor 1 connected to a controllable valve 2, a control electrode of which through threshold element 3, a phase-shifting circuit 4 with a capacitor 5 at the output, an emitter follower on the transistor 6 and an amplifier connected to the coil 7 of the torque sensor with core 8. Coil 7 and the core 8 tachometer installed with the possibility of changing the air gap between them. The amplifier is push-pull on transistors 9 and 10. The coil 7 of the tachometer is installed in the area of action of the dissipation windings of the electric motor 1. The electric drive is turned on by the switch 11.

When the switch 11 is turned on, the transistors 9, 10 and 6 are closed and the capacitor 5 starts to charge during each half-period of the mains voltage. This causes the voltage on the capacitor of the phase-shifting circuit 4 to increase to the trigger voltage of the threshold element 3. At the same time, the unlocking angle of the controlled valve 2 gradually increases. Simultaneously with the increase in the current of the electric motor 1 in the coil 7, the dissipation flows of the windings of the electric motor 1 increase, which induce a voltage in it proportional to the current value. This voltage opens the transistor 9 or 10 depending on the polarity of the signal. The transistor 6 also opens and shunts the capacitor 5. This limits the voltage on the capacitor of the phase-shifting circuit, which accordingly limits the unlocking angle of the controlled valve 2.

With the beginning of the movement of the electric motor 1, a voltage proportional to the frequency of rotation appears on the coil 7 of the tachometer. Further start-up and operation at a given frequency in | elapsed occurs under the action of a sum signal proportional to the frequency of rotation and the magnitude of the current of the electric motor 1. This signal provides a certain conductivity

transistors 9, 10, and 6, which determines the unlocking angle of the controlled valve 2, corresponding to a fixed rotation frequency.

Thus, the start-up of the electric motor 1 is carried out smoothly, taking into account the influence of the magnitude of the load and the moment of inertia of the first half of the parts,

which determine the change in current, i.e. The motor feedback current of the motor 1 operates in the system.

In the event of a load increase, the rotation frequency decreases, hence

the voltage value of the tachometer is reduced. As a result, the conductivity of the transistors 9, 10 and 6 decreases, the voltage on the capacitor 5 increases, which reduces the charging time

the capacitor of the phase-shifting circuit 4 and increases the unlocking angle of the controlled valve. The voltage applied to the motor 1 increases as the rotational speed increases. The stability of this process is provided by the negative current feedback of the electric motor 1.

When reducing the load occurs

reverse process.

Thus, the electric drive maintains a predetermined rotational speed by feedback on the rotational frequency.

To regulate the rotational speed, it is sufficient to change the conductivity of the air gap between the coil 7 and the ferrite core B, which turns on the voltage value

coil 7, which in turn affects the conductivity of transistors 9, 10 and 6 and, therefore, the unlocking angle of the controlled valve 2 will change. The frequency of rotation of the electric motor will change until the voltage on coil 7 former value. The system will come in steady state

but at a different rotational speed.

Thus, the control of the rotational speed, maintaining it at a given level and the smooth start of the electric motor is carried out by a contactless device acting as a unit for the frequency of rotation, as well as a feedback sensor for the motor of rotation and current. It increases reliability and sobl

51525851

service (absence of parts) the amplifier is connected to the coil of the tacho electric drive, provides a sensor with a core, which is affected by the destabilizing effect, and so that, with the aim of increasing factors, different. reliability and quality of operating conditions (availability of wrapping, coil and core of tachore bonds). sensors are installed with

Claims (2)

1. Electric drive containing electric motor connected to control unit 2. The actuator of claim 1, which is a valve that controls the electrode, so that the coil which, through the threshold element, the F-tachometer is installed in the zone of the deizo-shift circuit - with the capacitor of the flow of dissipation windings at the exit, an emitter follower and an electric motor.