RU2450409C1 - Asynchronous double-speed motor - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: motor consists of body with stator with low and high speed windings mounted in slots, rotor fixed at motor shaft and box of inputs with through joints connected to outputs of specified windings. According to invention winding changeover device is located at motor body; input terminals of the motor should have facilities for connection of feeder current-carrying leads and output terminals of winding changeover device should be connected electrically with through joints connected to outputs of motor windings. Winding changeover device can be located in box of inputs; for this purpose two outputs of this device should be connected through its break-type contacts to outputs of low speed windings of the motor and two outputs through normally open contacts of device should be connected to through joints, which are connected to high speed windings of the motor. Third outputs of low and high speed windings should be interconnected and then connected to the third through joint in box of motor inputs.

EFFECT: simplification of power supply system structure, improvement of control and protection, enhancement of reliability and operation of asynchronous double-speed motors due to their power supply by one cable and due to motor control and protection by one device instead of two devices.

2 cl, 2 dwg

Description

The invention relates to electrical engineering, in particular to asynchronous two-speed electric motors.

A known asynchronous electric motor, which consists of a housing in which a stator with a winding is mounted, a rotor located on the shaft, and input boxes designed to introduce a cable through which power is supplied to the electric motor. In this box there are also 3 passage clamps connected to the terminals of the stator winding, to which current-carrying conductors of the supply cable are connected [1].

Such electric motors are characterized by such a disadvantage as the impossibility of changing the shaft rotation speed without changing the frequency of the supply voltage, which does not allow you to adjust the speed of the mechanism, which is driven, for example, by a conveyor, and leads to increased energy consumption when the mechanism is not loaded and all the electric motor power is not needed.

Two-speed electric motors are also known, which coincide with the proposed invention in most basic respects and consist of a housing in which a stator with low and high speed windings is mounted, a rotor located on the shaft, and input boxes with two cable entries and bushings, each of which connected to the corresponding output of the windings of both low and high speed [2].

Such electric motors have a number of disadvantages, such as complexity, insufficient reliability and safety of the control and protection system, as well as the electric motors themselves. This is because in order to power such an electric motor, two cables are needed, connected respectively to the low and high speed windings, as well as two control and protection devices. In this case, the scatter of the characteristics of the control apparatuses, in particular, in terms of their speed leads to the fact that the inclusion of high speed windings occurs either when the low speed windings are still not turned off, or to their inclusion with a significant time interval after switching off the indicated low speed windings. The electric motor and transmission elements of the mechanism, which is driven by it, are subjected to significant mechanical and electrical shock overload, which leads to a decrease in their reliability. In addition, the induction of significant voltage on a disconnected winding of low or high speed and the absence of protective equipment at this connection leads to an increased risk of electric shock to people and, in mines and mines with explosive atmospheres, to the possibility of its explosion.

The objective of the proposed invention is to simplify the design of the electric motor, as well as the power supply system, control and protection, increase the reliability and safety of operation of asynchronous two-speed electric motors.

To this end, in the well-known asynchronous two-speed electric motor, which consists of a housing, a stator with low and high speed windings mounted in its grooves, mounted in the housing, a rotor mounted on the motor shaft, and an input box with passage clamps connected to the terminals of the windings, it is proposed place on the motor housing a switching device for its windings, to the input terminals of which to connect the conductors of the supply cable, and its output terminals to connect with the specified passage clamps moms. The design of the proposed electric motor is also characterized in that the said switching device is mounted in its input box, two terminals of which are connected to its opening contacts are connected to the feed-through terminals connected to the terminals of the low speed winding, and two terminals connected to the closing contacts of the device are connected with passage clamps that are connected to two terminals of the high speed windings, and the third terminals of the low and high speed windings are connected to each other and to the passage clamp, to one of which is connected to a current-carrying core of the supply cable, and the switching device is designed so that it does not have normally sparking parts. For this, the power circuits of the device are made on vacuum interrupter chambers, the control cores of the power cable are directly connected to the coil of the electromagnetic drive of the switching device.

The above essential features of the invention, which differ from the prototype, are necessary and sufficient in all cases to which the scope of legal protection of the invention applies.

Fastening the switching device of its windings to the electric motor housing makes it possible to supply such an electric motor via one cable from one control and protection device instead of two and to exclude voltage supply to the cable disconnected from the power source and the terminals of the switched off control and protection device, since they are absent.

This greatly simplifies the system of power supply, control and protection of the proposed electric motor and increases the safety of its operation.

To a significant simplification of the design of the proposed electric motor leads the placement of the switching device of the windings in its input box with the possibility of connecting two cores of the supply cable directly to the input terminals of the specified device and connecting the terminals of one phase of the low and high speed windings to each other and with a common passage clamp for them. For electric motors that operate in explosive atmospheres, the installation of products that have normally sparkling parts in the input boxes is prohibited. The proposed embodiment of the switching device of the windings allows you to place it in the input box of the motor without limiting the conditions of its application.

The proposed invention is explained by the drawings, which show a two-speed electric motor with an integrated winding switching device:

- in Fig. 1 - side view;

- Fig. 2 is a rear view.

An asynchronous two-speed electric motor consists of a housing 1, a stator 2 with low and high speed windings mounted in its grooves, fixed in the housing 1, a rotor 3, mounted on the shaft 4, terminal box 5 with bushings 6, 7 and 8, switching devices for windings 9 with input terminals 10 and output terminals 11. The input box has a cable entry 12 through which the power cable 13 is introduced into the input box 5.

An asynchronous two-speed motor works this way.

When applying voltage to the current-carrying conductors of the supply cable 13, the voltage through the input terminals 10 and the included contacts of the switching device of the windings 9 is fed through the through terminals 6 to two phases of the terminals of the low-speed motor winding. The voltage of another phase is supplied via cable 13 directly to the passage clamp 8 connected to the terminals of the low and high speed windings. As a result, voltage is applied to the low speed winding and the motor is turned on at low speed.

To switch the motor to high speed from the control apparatus, voltage is supplied to the coil of the electromagnet of the drive of the winding switching device. This device operates, disconnects the low speed windings and turns on the high speed windings, since it removes voltage from the passage clamps 6 and supplies it to the passage clamps 7. In this case, the rotor 4 of the electric motor starts to rotate at high speed.

To switch the motor to low speed, it is necessary to remove the voltage from the winding of the electromagnet of the switching device of the windings 9 and turn it off.

The combination of the functions of turning on and off the motor windings in one switching device - the winding switching device allows switching the motor windings almost instantly, while guaranteeing that the motor cannot operate when the windings are both low and high speed. This dramatically increases the reliability of both the electric motor itself and the mechanism that it drives.

Information sources

1. USSR author's certificate No. 633115, H02K 9/22. Electric car. Bull. No. 42, 1978.

2. Product catalog of OJSC Donetsk Electrotechnical Plant. Explosion-proof engines ADVK 315 M12 / 4, ADVK 355 LA 8/4 series.

Claims (2)

1. An asynchronous two-speed electric motor, which consists of a housing, a stator with low and high speed windings mounted in its grooves, mounted in the specified housing, a rotor mounted on the motor shaft and the input box with bushings connected to the terminals of these windings, characterized in that a switch device for its windings is installed on the indicated motor housing, the input terminals of which are equipped with devices for connecting current-carrying conductors of the supply cable, and the output terminals s of said winding switching device are electrically connected to bushings which are connected to terminals of motor windings. 2. An asynchronous two-speed motor according to claim 1, characterized in that the winding switching device is placed in the input box, two outputs of this device through its opening contacts are connected to the terminals of the low speed winding of the electric motor, and two outputs through its closing contacts are connected to the passage clamps, connected to the terminals of the high speed winding of the electric motor, and the third terminals of the high and low speed windings are interconnected and connected to the bushing in the input box of the electric motors Igater.

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