SU957343A2

SU957343A2 - Device for protecting asynchronous electric motor in tipping over

Info

Publication number: SU957343A2
Application number: SU813255273A
Authority: SU
Inventors: Владимир Васильевич Овчаров; Виктор Николаевич Евтушенко; Виктор Яковлевич Жарков
Original assignee: Мелитопольский Институт Механизации Сельского Хозяйства
Priority date: 1981-03-04
Filing date: 1981-03-04
Publication date: 1982-09-07

Description

1one

Изобретение относитс к электро-т технике, а именно к устройствам релейной защиты.The invention relates to electrical engineering, namely, relay protection devices.

По основному авт. св. № известно устройство дл защиты асинхронного электродвигател при опрокидывании , содержащее подключенную к датчику тока через выпр митель врем - . задающую цепочку, выполненную в виде соединенных параллельно конденсатора и резистора, и исполнительное реле, между конденсатором и. резистором дополнительно включен термистор, а исполнительное реле через динистор подключено к указанному резистору l.jAccording to the main author. St. A device for protecting an asynchronous motor during tipping is known, containing a time connected to the current sensor through a rectifier. driver circuit, made in the form of a parallel-connected capacitor and a resistor, and an executive relay, between the capacitor and. the thermistor is additionally connected by the resistor, and the executive relay is connected to the specified resistor l.j through a dynistor

Недостатком известного устройства вл етс то, что оно не защищает элек тродвигатель при неполнофазном режиме , когда ток потребл емый электродвигателем оказываетс меньшим дву- 20 кратной величины. Устройство не за щищает также электродвигатель при замыкани х обмоток электродвигател на корпус и между собой.:A disadvantage of the known device is that it does not protect the electric motor in the incomplete phase mode, when the current consumed by the electric motor is less than twice the value. The device also does not protect the electric motor when the motor windings close to the case and to each other .:

Л 2L 2

Цель изобретени - ра.сширение функциональных возможностей путем защиты электродвигател при обрыве фазы и коротких замыкани х обмоток на ко.эпус электродвигател и между собой независимо от величины потребл емого токз. электродвигателем.The purpose of the invention is to increase the functionality by protecting the motor during a phase failure and short-circuiting of windings on the electric motor and between each other, regardless of the amount of current consumed. electric motor.

Поставленна цель достигаетс тем, что в устройство между нулевой точкой электродвигател и динистором дополнительно включен диод, анод котрррго соединен с катодом динистора , а вывод термист;ора, соединенный .с отрицательной обкладкой конденсатора , заз-емлен.The goal is achieved by the fact that the device between the zero point of the electric motor and the dynistor additionally includes a diode, the anode is connected to the cathode of the dynistor, and the output is thermistor, the connector connected to the negative side of the capacitor is ground.

Claims

When one of the phases of the network is broken or when one of the motor windings closes on the case or when the motor winds close, the displacement of the motor zero point occurs and the zero point of the motor and charge terminate. As a result of the potential difference between the zero TOMKY and the ground, the voltage across the resistor increases to such a degree that the dynistor is unlocked and the intermediate relay is turned on, opening the power supply circuit of the coil of the magnetic motor starter. Such a constructive solution ensures the protection of the electric motor when one of the phases breaks. network, as well as the closure of the motor windings on the body and among themselves. The drawing shows the diagram of the Proposed Device. The device contains a current sensor 1 connected to it a rectifier 2, a capacitor 3 connected in parallel to the current sensor, a resistor t, a thermistor 5 and a series-connected distor 6 and an executive relay 7. Between the zero point of motor B and distor 6 A diode 9 is connected, the anode of which is connected to the cathode of the dynistor 6, and the output of the thermistor 5 connected to the negative capacitor plate is grounded. When one of the phases or closures of one of the motor windings of the body on the case or several windings breaks, the zero point of the electric motor is displaced relative to the ground. As a result of the voltage through the diode 9, the capacitor 3 is charged and the voltage across the resistor A increases until such a value, when dynistor 6 is unlocked, intermediate relay 7 is turned on, opening a circuit of the num. nor the coil of the magnetic actuator of the electric motor. In this case, the time delay of the protection operation is ensured automatically depending on the location of the closing of the windings (near the zero point of the electric motor or away from it), i.e. the greater the closing current, the faster the thermistor 5 heats up. its resistance decreases sharply, as a result of which the increase, the voltage across the resistor k, and the operation of the protection occur faster. Thus, the application of the proposed device allows to protect the electric motor not only when overturning, but also in the case of an incomplete phase mode, as well as during the closing of the windings on the motor body and between them. The invention The device for protection of asynchronous electric motor when tipping over. auth. St. No. that differs in that, in order to expand the functionality by protecting the motor when the Phase breaks and short-circuits of the windings on the motor housing and between themselves, between the zero point of the motor and the dynistor, the diode is additionally connected, and the output is the thermistor connected to the negative capacitor plate is grounded. Sources of information taken into account in the examination. 1. USSR author's certificate №, cl. H 02, 1975 /

yo

Z

7

a

U w

/ A