SU922537A1 - Device for checking thermal condition of immersible electric motor - Google Patents

Description

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The invention relates to thermal measurements, namely, devices for temperature control, submersible electric motors operating in drive pumps for extracting fluid from wells, as well as in any other installations requiring remote monitoring of their thermal state.

A device for temperature control is known, which contains a temperature-sensitive capacitor included in an oscillating circuit included in an auto-oscillator. When the temperature in this device changes, the frequency of the oscillator changes, which is recorded by the recorder.

The disadvantage of the device is that it does not provide high accuracy of temperature measurement with remote temperature control.

Closest to the proposed technical entity is a device for measuring temperature, containing an oscillating circuit with a thermosensitive capacitor, installed on an object whose temperature is measured, a high-frequency generator, a receiving unit. In this device, a high frequency oscillator excites oscillations in the circuit, the resonant frequency of which varies with temperature. The change in the resonant frequency is recorded by the receiving unit 2.

The disadvantage of the device is that it is impossible for them to provide with high accuracy the remote measurement of the temperature of the submersible electric motor.

. The purpose of the invention is to improve the accuracy of temperature measurement;

The goal is achieved by the fact that the device containing

Claims (2)

The first oscillating circuit with a thermosensitive capacitor installed in the electric motor, the high-frequency oscillator and the receiving unit located on the nosefix and connected to the power white of the electric motor, a second oscillating circuit and a low-frequency generator connected to the high-frequency generator, and the second oscillating circuit located in an electric motor, inductively coupled to the power cable and connected via a diode to the first oscillating circuit connected to. power cable capacitive coupling. The drawing shows the layout of the device. The device contains an oscillating circuit 1 consisting of a heat-sensitive capacitor 2, such as a ferroelectric, and inductance 3, a second oscillating circuit consisting of capacitor 5 and inductance 6, diode 7, capacitor 8, low-frequency generator 9, high-frequency generator 10, the receiving unit 11. The receiving unit 11 and the high-frequency generator 10 are connected to a power cable 12 connecting the motor winding to the power line and acting as a transmitting and receiving antenna of the high-frequency and low-frequency signals. Oscillating circuits 1 and 4 are located in the electric motor and are connected to the power cable through capacitive and inductive coupling. In the particular case, the oscillating circuits can be connected to the winding of the electric motor connected to the power cable. The device works as follows. The oscillatory circuit 1 is tuned to resonance at the frequency of the low-frequency oscillator, and the oscillatory circuit C is tuned to the frequency of the high-frequency oscillator signal. The signal from the high-frequency generator, modulated by the low-frequency signal, oscillates in the oscillatory circuit 4. The signal arising on the oscillatory circuit ij, through diode 7, which detects this signal 7 and extracts the low-frequency signal, is fed to oscillatory circuit 1, in which low frequency oscillations. A change in motor temperature causes a change in the capacitance of a thermosensitive capacitor, and, consequently, a change in the resonant frequency of the oscillating circuit C. A change in the resonant frequency causes a change in the amplitude of the signal excited in this circuit, which is recorded by the receiving unit. The presence in the proposed device of a second oscillatory circuit and a diode favorably distinguishes it from the known device, since it allows an increase in the languor of the temperature measurement, as well as expanding the scope of application of the device. Apparatus of the invention, for monitoring the heat and pressure state of a submersible electric motor, comprising a first oscillating circuit with a heat-sensitive capacitor installed in an electric motor, a high-frequency generator and a receiving unit located on the surface and connected to an electric motor power cable, characterized in that to improve the accuracy of temperature measurement, a second oscillating circuit and a low frequency generator connected to a high frequency generator, the second to The oscillator circuit is located in the motor, inductively coupled to the power cable, and connected via a diode to the first oscillating circuit connected to the capacitively coupled power cable. Sources of information taken into account during the examination 1. USSR author's certificate No. i 06l33, cl. G 01 K 7/3, 1971. 2. US patent number 2818732, cl. 73-362, published. 1958 (prototype). LZZLTZHJ L.