SU922542A1 - Device for measuring electrical machine winding temperature - Google Patents

Description

I

The invention relates to a technique for measuring temperatures and can be used in the field of automation of production processes, namely, to measure the temperature of the stator windings of electric machines in an operating mode.

A device for measuring the temperature of the windings of electrical machines is known, comprising a thermal sensor in the form of a winding of an electric machine, a current transformer, a constant current source til,

The drawback of the device is the low accuracy of temperature measurement due to the presence of a variable component of the electric current in the measuring circuit.

Closest to the present invention is a device for measuring the temperature of the windings of electric machines, comprising a thermal sensor in the form of a winding of an electric machine, two analog-storage units, outputs

which are connected via rectifiers to the inputs of a dividing element connected to the measuring device 121.

The drawback of the device is the low accuracy of temperature measurement when the electric machine is operating under load.

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

ten

The goal is achieved by using a device, a block, controls, two thyristors and a simistor, connected to a thermal sensor, the zero point of which is connected to the common

Claims (2)

15 to the output of analog-storage blocks, the information inputs of which are connected via thyristors to the connection point of a thermal sensor and a triac, to the control electrode of which a first output of the control unit is connected, the second and third outputs of which are connected to the control electrodes of the thyristors, and the fourth output connects Control inputs for analog-storage blocks. The drawing shows a diagram of a device for measuring the temperature of windings of electric machines. The device contains a three-phase electric machine with windings 1 and 2 and winding 3, which is a thermal sensor. Thermal sensor is connected in series with triac f. Anode thyristors 5 and 6 are connected to the junction point of the thermal sensor and triac, the cathodes of which are connected to the first poles of the first inputs of analogue current blocks 7 and voltage 8, the second poles of the first inputs are combined and connected to the common zero point of the windings electric car. The outputs of analog-storage units through rectifiers 9 and 10 are connected to a separating element 11, and a measuring device 12 is connected to the output of a separating element, indicating the temperature of the winding of the thermal sensor. The four outputs of the control unit 13 are respectively connected to the control electrodes of the triac, the thyristors, and the common point of the control inputs of the analog-storage blocks. The device works as follows. In the working position, a mains voltage is applied to the leads of the phase windings 1-3, the control unit 13 is simultaneously turned on, and the unlocking voltage is applied to the control electrode of the triac C, while the thyristors 5 and 6 are disconnected. To measure the temperature of the winding of an electric machine, for example winding 3, the control unit turns off the triac, and thyristors 5 and 6 are supplied at a certain phase of the supply voltage due to the measurement program, the control pulses of the unlocking thyristors 5 and 6, the amplitude of the EMF of rotation is removed between the working phase 3 and the common zero point of the phase windings are stored in the analog storage unit 8 voltage, and the amplitude value joKa passing through the winding 3 is stored in the current unit 7. From the outputs of analog-storage blocks 7 and 8 via rectifiers 9 and 10, respectively, analog voltages, proportional to the emf of rotation and current. passing through the winding 3, is fed to a dividing element 11, in which the temperature-dependent resistance of the winding 3 is calculated. A measuring device 12 indicates the temperature of the winding 3 of the electric machine. The shutdown time of the working phase in which winding 3 is connected for measuring temperature at a mains frequency of 50 Hz does not exceed 10 ms. To take the next temperature reading from the working phase of the winding 3, the control unit 13 is given a command to reset the readings from the analog storage units 7 and 8, and the measurement is repeated. Thus, the present invention allows to accurately, quickly and reliably determine the temperature of the windings of an electric machine and can be used in appropriate automatic control systems. The invention The device for measuring the temperature of the windings of electric machines, containing a sensor in the form of a winding of an electric machine, two analog-storage units, the outputs of which are connected via rectifiers to the inputs of a dividing element connected to a measuring device, characterized in that, in order to improve the accuracy of measurement , a control unit, two thyristors and a triac connected to a thermal sensor are inserted into the device, null. the point of which is connected to the common output of analog-storage blocks whose information inputs are connected through thyristors to the point of connection of the thermal sensor and triac, to the control electrode of which the first output of the control unit is connected, the second and third outputs of which are connected to the control electrodes of the thyristors, and the fourth the output is connected to the control inputs of analog storage units. Sources of information taken into account in examination 1, USSR Copyright Certificate ff 781613, cl. U 01 K 13 / 08,1978. 2. For the USSR № 27 + 8726 / 18-10, cl. G 01 K G3 / 08, 09.0} .79 (prototype).