SU1163426A1 - Electric motor with unit for measuring mechanical characteristic - Google Patents

Abstract

ELECTRIC MOTOR WITH BLOCK FOR MEASURING A MECHANICAL CHARACTERISTIC, containing a torque measurement sensor in the form of a strain gauge bridge connected to an AC source and installed on the motor shaft, a rotational speed sensor and a recorder to which torque and frequency sensors are connected, characterized in that simplifying the device, it is equipped with a toroidal coil connected to a constant-current source and a full-wave switch, while the coils are mounted concentrically with the motor shaft He was in the area where the strain gauges are located, and the rectifier is connected between the outlet of the strain gauge bridge and the recorder. SL C5 oo 4 th 05

Description

The invention relates to electric machines, namely, electric machines with devices for technical diagnostics of their condition.

The purpose of the invention is to simplify the device.

FIG. 1 shows the electrical circuit diagram of the mechanical characteristic measurement unit; in fig. 2 is a diagram of the mutual deposition of sensors and coil relative to engine waves; in fig. 3 is a graph of vrash, the current moment and frequency of the vrash.i electric motor in time.

A measuring unit is installed on the magnetic conductor W. shaft 1 of the engine, containing strain gauges 2 included in the strain gauge. Concentric to the shaft 1 is the stirring, the toroidal coil 3, connected to the direct current source. The strain gauges 2 are located in the field of the coil 3. The strain gauge is connected to an AC source, and its output through the switch 4 and the current collectors 5 is connected to the recorder 6. In FIG. 3 - marked around the 7 measured signal, built by connecting the maximum values of the amplitudes of sinusoids modulated by the envelope of the zero line of the alternating current signal 8. The instantaneous values of the ordinate 9 correspond to the value of the moment, and the ordinates 10 relative to the initial zero line 11 correspond to the instantaneous values of the rotation frequency.

Strain gauges 2, pasted on the shaft, are included in the bridge circuit (Fig. 1) and form a closed loop penetrated by the magnetic flux of the toroidal coil 3, mounted centrically with the shaft. Due to the mutual arrangement of the flow and the contour in the circuit, a constant emf is induced akin to the origin of emf induced in unipolar machines.

In the experiments, wire strain gauges are used.

The test motor is started, after which the strain gages 2 are fed with alternating current, and the toroidal coil 3 is connected to a direct current source. In order to clarify the principle of forming the measuring signal (Fig. 2) of the tense bridge, the measuring wires are replaced by the conductor ab.

Around the magnetic conductive tensal 1 there is a magnetic field F of unchanged polarity created by a toroidal coil 3 mounted centrically with a strainer shaft 1. The output signal from the strain gauge is supplied by means of current collectors 5 (for example, rings and lead wires) to the recorder 6. When rotating, tenses 1 in two parallel circuits, emfs of equal magnitude and equal in direction are directed, the magnitude of which is proportional to the magnetic flux induction and the rotation frequency of the tensed to 1. When the flow is constant, the toroidal cat 3, the value ki induced EMF proportional to the frequency

5 rotations The value of this EMF corresponds to curve 8 (Fig. 3). At the same time, an alternating signal appears in the output of the strain bridge, proportional to the torque, which rectification by rectifier 2 ensures fixation of the envelope 7, built by connecting the maximum values of the amplitudes of the sinusoids modulated by the curvature of the alternating current zero line 8. Instantaneous values of the ordinates 9 correspond to meaning

5 torque, and ordinates 10 relative to the initial zero line 11 correspond to the instantaneous values of the rotation frequency.

The rigid attachment of the cable cores to the shaft I and the strain gauge and its clamping joint 0 with the AC source and the recorder 6 during run-up provide reliable recording of both curves. When re-registering the cable is easy to unwind and restore the scheme.

5 The technical advantage of the proposed device in comparison with the known is the continuity of the recorded signal using a wide class of recorders, which allows to determine with high accuracy the instantaneous values of the minimum, maximum and starting moments at strictly fixed corresponding rotational frequencies.

In this case, one recorder and a strain gauge are used to record two signals proportional to the rotational speed and moment, which simplifies the measurement device.

Phage. 2

Claims (1)

ELECTRIC MOTOR WITH A UNIT FOR MEASURING MECHANICAL CHARACTERISTICS, comprising a torque measuring sensor in the form of a strain gauge bridge connected to an AC source and mounted on the motor shaft, a speed sensor and a recorder to which torque and speed sensors are connected, characterized in that, for the purpose of To simplify the device, it is equipped with a toroidal coil connected to a constant current source and a half-wave switch, while the coils are mounted concentrically to the motor shaft in not placing strain gauges, and a rectifier connected between the output of strain gauge bridge and registrars FIG. ί