SU691986A1

SU691986A1 - Apparatus for protecting an electric motor against temperature rise

Info

Publication number: SU691986A1
Application number: SU772552254A
Authority: SU
Inventors: Анатолий Порфирьевич Казимир; Ирина Евсеевна Керпелева; Константин Александрович Шаповал
Priority date: 1977-12-08
Filing date: 1977-12-08
Publication date: 1979-10-15

Description

(54) УСТРОЙСТВО ДЛЯ ЗАЩИТЫ ЭЛЕКТРОДВИГАТЕЛЯ ОТ ПОВЫШЕНИЯ ТЕМПЕРАТУРЫ(54) DEVICE FOR PROTECTING THE ELECTRIC MOTOR AGAINST TEMPERATURE INCREASE

1one

Изобретение относитс к области электротехники и может быть использовано дл защиты электродвигател от повышени температуры при ненормальных режимах его работы.The invention relates to the field of electrical engineering and can be used to protect an electric motor against temperature increase during abnormal modes of its operation.

Известны устройства дл защиты электродвигател от повышени температуры, содержащие термодатчики, помещенные в обмотках двигател , пороговые элементы, дифференцирующее звено, элементы И и ИЛИ и исполнительный элемент 1. Такие устройства, хот и обеспечивают отключение электродвигател при недопустимом повышении температуры его обмоток и при чрезмерной скорости ее нарастани , недоста Точно точно определ ют скорость нарастани температуры и вследствие этого недостаточно чувствительны.Known devices for protecting an electric motor against temperature rise include thermal sensors placed in the motor windings, threshold elements, a differentiating element, AND and OR elements, and an actuating element 1. Such devices, although they ensure the disconnection of the electric motor when the temperature of its windings is unacceptable and at excessive speed its growth is not sufficiently accurately determine the rate of increase in temperature and consequently not sensitive enough.

Наиболее близким к изобретению по технической сущности вл етс устройство дл защиты электродвигател от повышени температуры , содержащее датчики температуры , помещенные в обмотках защищаемого электродвигател и соединенные через первый пороговый элемент и элемент ИЛИ с исполнительным элементом, второй и третийThe closest to the invention to the technical essence is a device for protection of an electric motor against temperature increase, containing temperature sensors placed in the windings of the protected electric motor and connected through the first threshold element and the OR element to the actuating element, the second and third

пороговые элементы также присоединены к датчикам температуры, выход второго порогового элемента подключен к элементу И, к другому входу которого через одновибратор присоединен выход третьего порогового элемента, а выход элемента И соединен с элементот ИЛИ 2. Однако и это устройство недостаточно чувствительно, поскольку оно контролирует нарастани температуры обмоток двигател в узком диапазоне температур, а начальна температура об.мотки не учитываетс .threshold elements are also connected to temperature sensors, the output of the second threshold element is connected to the AND element, to the other input of which the output of the third threshold element is connected through the one-shot and the output of the AND element is connected to the OR elements 2. However, this device is not sensitive enough, because it controls the buildup motor windings in a narrow temperature range, and the initial winding temperature is not taken into account.

Целью изобретени вл етс повышение чувствительности устройства путем контрол скорости йарастатйгйй тейтературы обмоток во всем диапа3оне рабочих температурThe aim of the invention is to increase the sensitivity of the device by controlling the speed of the most variable teterature of the windings in the whole range of operating temperatures.

двигател . Это достигаетс тем, что предлагаемое устройство дополнительно снабжено интегратором, релейным элементом с суммируюшими входами, генератором тактовых импульсов и элементом задер йки; при этом выход термодатчика соединен с первымвходом релейного элемента и первым входомengine This is achieved by the fact that the proposed device is additionally equipped with an integrator, a relay element with summing inputs, a clock pulse generator and a delay element; the output of the sensor is connected to the first input of the relay element and the first input

интегратора, выход которого соединен со вторым входом релейного элемента, выход гене:integrator, the output of which is connected to the second input of the relay element, the output of the gene:

Claims

A clock pulse clock is connected to the third input of the relay element by a non-conventional and via a delay element to the second input of the integrator, and the output of the relay element is connected to the input of the OR element. FIG. 1 is a block diagram of the device described; in fig. 2 - his, schematic diagram. Thermal sensor 1, placed in the windings of the protected electric motor, is connected to threshold element 2, which is connected via element 3 OR to actuator 4. The output of thermal sensor 1 is also connected to the first input of relay element 5 directly and to its second input through integrator 6. Generator; clock pulses connected to the third input of the relay element 5 and through the delay element 8 to the second input of the integrator 6. Thermal sensors 1 are formed by the series connection of thermistors with resistors and constitute a temperature to voltage converter. Thermistors have negative temperature coefficients and are placed one in the winding for each phase. To match the output of the thermal sensor 1 with the inputs of elements 2 and 5 and the integrator 6, an emitter follower assembled on opposite polarity transistors is used. Elements 2 and 5 are made on operational amplifiers and are included in an open circuit comparison of currents. The integrator 6 contains an operational amplifier 9, the output of which is connected to the capacitor 10 and the input of the source follower assembled on transistors 11 and 12, the output of which is connected to the inputs of the element 5. The output of the pulse generator 7 is connected to the input of the element 5 and through the delay element 8 made. in the form of a two-phase one-vibration connection, with the input of the integrator 6. The actuating element 4 is made on a transistor, the load of which is an optoelectronic resistor controlling the electronic key assembled on the thyristors. The latter controls the operation of the magnetic starter. The device works as follows. When the permissible rate of increase in the temperature of the windings (less than 3 degrees) from the moment of switching on under the voltage of the electric machine or the device, there is no signal at the output of the relay element 5. The shutdown of the protected electrical equipment in this case can occur only when the insulation windings reach the maximum permissible temperature value, which is controlled by the threshold element 2. In this case, the threshold element through the element 3 OR outputs the corresponding signal to the actuator 4. In the case of thermal insulation shock (temperature increase rate windings are higher than 3 degrees, c), which can take place even from the moment of switching on the electric machine or device under voltage at, at the output of the relay element 5 It is a signal which passes through the element 3 or on the actuating element 4. Last instructs the immediate shutdown of the protected apparatus. Introduction to the proposed device of additional elements and the connections between them makes it possible to respond to the rate of increase in the temperature of the insulation not in a narrow area, but from the moment of switching on the electrical maschine or apparatus under voltage at any ambient temperature. As a result, the service life of the electric motors is significantly increased. An apparatus for protecting a motor against temperature increase, comprising a power source and a thermal sensor placed in the windings of the motor to be protected, the output of which is connected through a threshold element and an OR element to an actuating element, in order to increase the sensitivity by controlling the rate of temperature rise of the windings in the whole range of engine operating temperatures, it is additionally equipped with an integrator, a relay element with summing inputs, a clock generator output pulses and a delay element, while the output of the sensor is connected to the first input of the relay element and the first input of the integrator, the output of which is connected to the second input of the relay element, the output of the clock generator is connected to the third input of the relay element directly and through the delay element to the second input of the integrator, but. the output of the relay element is connected to the input of the OR element. Sources of information taken into account in the examination 1. USSR author's certificate number 152497, cl. H 02 H 5/04, 1962.

2. USSR author's certificate number 542290 cl. H 02 H 7/08, 1976.