UA24089U - Method for measuring internal temperature of a winding of an electric machine, transformer, or inductor - Google Patents

Abstract

The proposed method for measuring internal temperature of a winding of an electric machine, transformer, or inductor by a thermistor temperature transducer is distinctive by using, as the material of the thermistor, a section of carbon fiber that is arranged at the point of the temperature measurement. The thermistor is inserted in the measuring circuit of the transducer.

Description

Description of the invention

The useful model belongs to the field of electrical engineering, in particular, to systems for measuring the temperature of stator windings 2 of electric machines, transformers and chokes.

Known methods use thermoresistive and thermoelectric elements (|Metrology and measuring technique. Edited by Prof. Polishchuk. Lviv, "Beskid Bit" publishing house, 2003, 513 p., p. 4721.

But it is quite difficult to measure the temperature with the help of these elements in the inner part of the coils or in the groove of the stator of an electric machine: firstly, these elements are metal and can damage the insulation of the wires, 70 secondly - for their location, additional space is needed, which is usually lacking. These disadvantages are also valid for posistors (Kuznetsov R.S., Stroganov N.I. Posistor protection of electric motors. "Zlektrotehnika", 1980, Mo12, p.26-28.1. At a high rate of increase in the temperature of the windings, the posistor protection is activated with a delay, which leads to overheating of the insulation, and therefore to its accelerated wear |Stroynikov V.G.

Dynamic error of the built-in temperature protection of alternating current electric motors.

Electrical engineering and electromechanics. 2005, Mo1, p. 634. That is, the known elements have disadvantages both in dynamic properties and in the possibility of their location inside the coils and sections of the stators.

The useful model is based on the problem of temperature measurement using a carbon thread, which is not a metal, has a high resistance, a small diameter of 0.2:0.5 mm, a relatively large temperature coefficient, a significant temperature resistance (up to 10002С), as well as a low specific mass , which is important for the speed of its heating.

The task is solved by the fact that for the possibility of placing the measuring element directly on the turns of the wire inside the coils and ensuring higher accuracy, reliability and speed of operation, carbon filaments are used as the material of the thermoresistive element, which are located directly inside the windings in places where it is necessary to measure the temperature, and to which, with the help of an electronic switch, are alternately connected to a microprocessor device, which calculates the resistance values based on the results of the measurements. -

The essence of the useful model is explained by the list of Fig. 1, 2, Z 4.

Fig. 1 shows the experimentally determined dependence of resistance on temperature for HV with a diameter of 0.2 mm and a length of 5 Ω; in Fig. 2 and C - diagrams of the location of the carbon thread on the coil of the transformer and the section of the stator winding of the electric machine; in Fig. 4 - connection of HV terminals to the ring insulating plate. F

It can be seen from Fig. 1 that when the carbon filament sample was heated from a temperature of 5092С to 2502С, its resistance decreased from 800 to 640Ω, that is, the temperature coefficient of 250-550 200

When using a sample to measure temperature, the latter can be measured as teb-50-0.8.dK-50-0.8(800-Kvn), where Kvn is the resistance of the carbon thread sample. "

To measure the temperature of the transformer coil between the primary and secondary windings, a thread must be wound on the wire of the primary winding as shown in Fig. 2: 1 - cheek of the coil, 2 - secondary winding, C - - c primary winding, 4 - carbon thread, 5 - bandage, which is used to fasten the ends of the carbon thread on the cheeks of the coil. is" To measure the temperature in the sections of the windings, which are in the slots of the stator of the electric machine, carbon filaments are placed in the sections during their manufacture, as shown in Fig. Z, where 6 is the section of the winding, 7 is the terminals of the winding wires, and 8 is the terminals of the carbon thread. With the help of a bandage, the terminals are fixed to the ring co-textolite plate and then connected to the electronic switch, the circuit for measuring resistance and calculating their temperature, as well as to the indication and signaling device, as shown in Fig. 4, where 9 is a ring insulator, 10 - carbon fiber terminals, 11 - electronic switch, 12 - microcontroller, 13 - indicator with (а) image of section temperature in digital form or using a histogram. Data from the indicator 13 or 50 can be transmitted to the operator's console or the energy department of the workshop via radio communication.

Due to the low specific mass, the heating of the carbon thread takes place simultaneously with the heating of the insulation of the wire, therefore iChe) measuring devices will display the temperature of the insulation without lag.

The proposed method allows you to measure the temperature inside the windings, that is, in the most heated part. In this way, it is possible to prevent overheating of the windings, which means to prevent accelerated wear of the insulation. with

Claims (1)

The formula of the invention The method of measuring the temperature inside the stator windings of an electric machine and transformer coils and 60 choke using thermoresistive elements, which is distinguished by the fact that in order to place the measuring element directly on the turns of the wire inside the coils and ensure higher accuracy, reliability and speed, as the material of the thermoresistive element, carbon thread is used, which is located directly inside the windings in places where it is necessary to measure the temperature, and to which, with the help of an electronic switch, are alternately connected to a microprocessor device, which 65 calculates resistance values based on measurement results.