SU1457033A1 - Device for measuring the pressure of brush against electric machine commutator - Google Patents

Abstract

The invention relates to electrical engineering. The aim of the invention is the expansion of operational capabilities. The installation consists of an electric centrifuge, on the platform 6 of which an electric machine 3 is installed, and a control unit including an electrical element controlling the moment the brush is detached from the collector 4, a unit for varying the rotational speed of the centrifuge, a power supply unit for the electric motor 7 and a recording device | 0. A collector 4 is installed on the shaft of the electric machine 3, with which the brushes 1 are in contact. The electric j amHHa 3 is installed on the platform 6 of the centrifuge with radial displacement R relative to the center and oriented so that the pressure force of the test brush F. .. is directed to the rotation axis of the zeitrifuge. The centrifuge platform 6 is mounted on the drive motor shaft 11. When the centrifuge platform 1 rotates, the centrifugal force Hz acts on the brush, is proportional to the value (R + R) and tends to tear it away from the collector. The electrical signal from the breakaway control element 5 enters the control winding of the electromagnetic clutch 12, the mechanical coupling of the variable capacitor motor 11 is disconnected, the output signal frequency is interrupted, and the rotation frequency of the platform 6 with electric mask 3 is set constant. The recording device 10 fixes this frequency. The pressure force of the brush on the collector is determined by the well-known expression for centrifugal force. , 1 Il. 9i (L 4 SP hO from 00

Description

The invention relates to electrical engineering, in terms of creating devices for measuring the pressure force of a brush on the collector of an electric machine, and can be used for assembled electric machines, preferably of low power, under the conditions of their manufacture, research, operation and repair.

The aim of the invention is to expand the operational capabilities of the device.

The drawing shows a block diagram of the device for; measuring the force of the brush pressure on the collector of an electric machine.

The device contains the test brush 1 interacting with a collector 4 mounted on the shaft 2 of the electric machine 3 and connected to the brush 1 electrical element 5 controlling the moment of brush separation from the collector D "The device additionally contains an electric centrifuge with platform 6, unit 7 supplying the electric motor 8 busy by its input with a controllable unit 9 for changing the rotational frequency of the centrifuge 6. An electric control element 5 is included in the control circuit of the unit 9 for changing the rotational frequency. In parallel, the recorder 10, for example, a frequency meter, is turned on at the input of the power supply unit 7 of the electric motor.

An electric machine 3 is mounted on the rotating platform 6, while its radial displacement relative to the centrifuge platform rotation axis is fixed (the drawing shows a fixed radial displacement R of the axis of the shaft 2 of the machine relative to the axis of rotation of the platform 6) Machine 3 is installed on platform 6 so that the pressure force Fa the test brush 1 is directed to the axis of rotation of the platform 6 of the centrifuge.

Element 5 controls the moment of separation of the brush from the collector can be performed in different ways. In the simplest case, it is a current source (battery) and a light bulb connected in series with the I) brush-collector circuit of an electric machine. If you need a more detailed analysis of the process from 1) the brush from the collector, it can be executed as. a comparator (as in the prototype), one input of which is connected through a little

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a powerful source of direct current with the brushes under study, the second input is connected to the threshold level setter by a signal, and the output is connected via a switch to the indicator.

The centrifugal frequency changing unit 9 consists of an electric motor 11, an electromagnetic clutch 12 and a variable frequency generator 13. The shaft of the electric motor 11 is connected via an electromagnetic clutch 12 to the axis of the variable capacitor capacitor of the generator 13. Depending on the signal from the element 5 to the electromagnetic control winding clutch 12, it can be closed or open.

The electrical connection of the control element 5 with the brushes 1 is carried out, for example, through sliding contacts and contact rings (not shown, the connection is conventionally indicated by dashed lines) mounted on the axis of the centrifuge drive motor 8. It is possible that the control element 5 is located on the platform 6, and its connection with the block 9 of the change in the rotation frequency of the center is. The triphugs are carried out via a photocell.

The device works as follows.

When connecting the unit 9 for changing the rotational speed of the centrifuge to the power source, the electric motor 11 starts rotating the axis of the variable capacitor variable capacitor 13 of the variable frequency through a closed electromagnetic clutch 12. The output signal of the generator 13 is fed to the input of the power supply unit 7 of the centrifuge motor 8. The shaft of the electric motor 8, with the platform 6 fixed at its end, begins to rotate with increasing frequency.

When the centrifuge platform 6 rotates, the brush 1 is acted upon by the centrifugal force Rc, proportional to the value (R + K), (where R, is the distance from axis 0 (shaft 2) of electric machine 3 to the center of gravity of brush 1) and tear it away from the collector 4. When a certain value is reached, the speed (frequency) of rotation Q. of the platform is balanced.

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power of the GL and FM and the moment comes

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c

brush off the collector.

Depending on the performance and principle of the element 5 controlling the moment of separation, a corresponding electrical signal is generated at its output, which enters the control winding of the electromagnetic clutch 12. The last operation is triggered, the mechanical connection of the motor 11 with the variable capacitor 13 is disconnected, the process of increasing the frequency of the output signal interrupted, and the frequency of rotation of the platform 6 with the electric machine 3 is set constant. The recording device 10 fixes this frequency.

The pressure force of the brush 1 on the collector 4 is determined by the expression for the centrifugal force

Hz

m

(R +

R,) Q

where m is the mass of the brush.

If necessary, the device provides the ability to determine the force of the brush pressure over time, i.e. when a multi-pole electric machine is operating in engine mode. or on an electric machine whose shaft with the collector is forced to rotate from an auxiliary electric motor (as in the prototype). To do this, on platform 6, an electric machine and an auxiliary electric motor must be installed coaxially fixed, the shafts of which are directed oppositely and connected by a coupling. The power to the auxiliary electric motor is supplied from a special source through contact rings on the axis of the electric motor 8.

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The proposed device has a wide applicability, as it allows to perform pressure changes of the brush on the collector in any electric machines with different design of brush-collector nodes, regardless of whether there are windows in the zone of these nodes necessary for the mechanical connection of the brush with the load-bearing device, the need of which requires a known device.

Claims (1)

Invention Formula A device for measuring the pressure force of a brush on the collector of an electric machine, comprising an electric element controlling the moment of brush separation from the collector, associated with a recorder, characterized in that, in order to expand operational capabilities, it further comprises an electric centrifuge with a platform designed to be mounted on it electric machine, with a fixed radial displacement relative to the axis of the platform so that the pressure force of the brush examined is directed to the axis of rotation of the platform, while stroke motor power unit is coupled to the further inputted frequency control unit changes emym rotating centrifuge, the electric control element instant of detachment from the collector brushes included in the frequency changing unit centrifuge rotation control circuit and recorder is also included at the input of the power unit of the motor of the centrifuge.