SU1363368A1 - Arrangement for breakage protection of phases of three-phase motor - Google Patents

Abstract

The invention relates to electrical engineering and is intended for use in agricultural production facilities. The purpose of the invention is to increase reliability by providing the torque of an electric motor when operating in capacitor mode at 9A hV fC interruption of two phases of the power supply network and reducing dynamic overloads on the motor shaft when normal power is restored. When two phases are broken, for example, A and C, relays 1 and 3 are de-energized, which leads to switching of contacts 5 and 7. The terminal A1 is supplied with a voltage from the terminal B through a capacitor, and the terminal C is connected to the common conductor by the contact 17 of the relay 14 When the relay 14 is turned on, the contact 21 closes and the relay 24 operates, switching the contacts 28,29,30, which connect the stator windings of the motor in a delta circuit. With such a capacitor connection circuit, the full phase voltage is applied to the stator windings of the electric motor, which increases the torque of the electric motor. 1 il. from about 00 W about 00

Description

The invention relates to electrical engineering and is intended for use in agricultural production facilities.

The purpose of the invention is to increase reliability by providing the torque of an electric motor when operating in capacitor mode when the two phases of the mains supply are disconnected and to reduce dynamic overloads on the electric motor shaft when the normal power supply is restored.

The drawing shows a diagram of the device.

The device contains 1–3 control of phase voltages and capacitors 4, connected by their own to the phases of the mains supply by some voltages. The switching contacts 5–7 of the relay 1–3 are included in the supply lines of the motor windings from the network, and the disconnecting contacts 8–13 of these relays form the logic circuit for controlling the intermediate relays 14–16, which are equipped with the switching contacts 17–19. The inputs of the power supply 20. connected to the switching contacts 5 - 7 relays 1 - 3. control phase

stress The closing contacts 21, /, spite of that, after for example, 23 intermediate relays 14-16 form phase A are de-energized, relay 1 de-energizes relay 1, the control logic circuit of switching relay 24 is disconnected. The output terminals of static windings 25-27 of the electric motor are switched to leads to the switching of the contact 5 and the transfer of the engine to the two-phase condenser mode by connecting to the de-energized phase of condensation

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The pins 28 - 30 of the switching terminal - - torus 4, which ensures the preservation of the relay. Interview windings. Nick relay 14 16 and switching relay 24 are connected to the output of power supply 20, which ensures the normal operation of these relays in the presence of at least one of the supply mains voltage. A common power supply 20 is connected to the common conductor of the power supply. 17-19 intermediate relays 14-16, the switching contacts of which are connected to the initial outputs of the stator windings 25-27 of the motor to be protected and disconnecting to the inputs of the power supply source 20 and the switching contacts 5-7 of the relay 1-3 to phase control stress Closing contacts 28 - 30 switching relay 24

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the direction of rotation of the motor preceding the phase. When de-energizing the winding of one relay 1–3 of the control of phase voltages, intermediate relays 14–16 do not activate. If it is any other phase of the mains supply, the device works in the same way.

When the voltage of two phases, for example, A and C, fails, the mains supply de-energizes relays 1 and 3, which leads to closure of contacts 8 and 9 of relay 1 and closure of contacts 12 and 13 of relay 3. As a result, relay 14 is triggered, while terminal C1 with contact 17, the relay 14 is connected to the common power line of the mains. In addition, contact 21 of the relay 14 of the 14th closes and triggers the relay 24, which with its contacts 28-30 switches the stator windings of the electric motor from the star connection circuit to the triangle connection circuit. With such

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each are connected to the initial out-stator winding of the subsequent phase of the electric motor, and the disconnecting contacts 28 to 30 of the switching re

five

0

five

The 24 are connected to each other in a star. Phase-shifting capacitors are connected to the mains supply phases by 4 channels, and to the breaker contacts 5–7 of the relay 1–3 of the phase voltage monitoring, the closing contacts of which are connected to the mains supply phases; ,

The device works as follows.

In the normal power supply mode, when all three phases of the power supply are present, relays 1-3 are activated by connecting the electric motor, contacts 5-7, to the power supply. At the same time, contacts 8-13 of these relays open. Intermediate relays 14 - 16 do not work. Contacts 2 - 23 are open, relay 24 is also in an unresolved state. The motor is operated in full phase mode, in which the stator windings 25 to 27 of the motor are connected by contacts 28 to 30 in a star.

When voltage drops to any-. The buoy from the power supply terminals, for example, A, the device operates as follows. After the phase A voltage is lost, relay 1 is de-energized,

which leads to the switching of the contact 5 and the transfer of the engine to the two-phase condenser mode by connecting to the de-energized condensation phase

torus 4, which ensures the preservation

the direction of rotation of the motor preceding the phase. When de-energizing the winding of one relay 1–3 of the control of phase voltages, intermediate relays 14–16 do not activate. If it is any other phase of the mains supply, the device works in the same way.

When the voltage of two phases, for example, A and C, fails, the mains supply de-energizes relays 1 and 3, which leads to closure of contacts 8 and 9 of relay 1 and closure of contacts 12 and 13 of relay 3. As a result, relay 14 is triggered, while terminal C1 with contact 17, the relay 14 is connected to the common power supply line. In addition, the contact 21 of the relay 14 closes and triggers the relay 24, which with its contacts 28-30 switches the stator windings of the electric motor from the star connection circuit to the delta connection circuit. With such

the capacitor switch-on circuit on the stator windings 25-27 of the electric motor is supplied with full phase voltage, which makes it possible to increase the torque of the electric motor in this mode of operation by three times compared with the connection circuit in a star. After the voltage has been restored in all three phases of the mains supply and the motor is switched to full phase operation, the dynamic overloads on the motor shaft resulting from torque boost are significantly reduced, which increases the operational reliability of the drive.

Claims (1)

When the voltage in the other two phases of the mains supply fails, the device operates in the same way, while the voltage in phases B and C disappears, the intermediate relay 15 triggers, and when the voltages disappear in phases A and B, the intermediate relay 16. The formula of the invention A device for protection against the phase failure of a three-phase electric motor in a normal power supply mode, including a star, containing three phase voltage monitoring relays with windings for connecting to phase voltages of the supply mains, phase-shifting capacitors with one output for connection to the power supply phases1 network, and others connected to the opening contacts of the relay of control of the phase voltages, the closing contacts of which have leads for connection to the phases of the power supply network, the power source and three intermediate relays, one end bmotki each of which is connected to the output of the power source and the other end of the first auxiliary relay is connected via series connected razmykayuSostavitel O.Orloi Editor N.Slobod nick Tehred M.Hodanich KorrektorM.Pozho Order 6372/48 Circulation 6i8 Subscription VNISHI State Committee- USSR for inventions and discoveries 113035, MvicKBa, Ж-35, Raushsk nab., 4/5 Production) - printing company, Uzhgorod, st. Design, 4. the first and third, second intermediate relays — through the opening contacts of the second and third g, third intermediate relays — through the disconnecting contacts of the second and first phase voltage monitoring relays to the common power source intended to be connected to 0 to the common power line conductor, for connection to which the closing contacts of three intermediate relays, whose switching contacts have terminals 5 for the connection with the initial outputs of the stator windings of the protected motor, and the disconnecting ones with the inputs of the power source and the switching contacts of the phase control relay 0 voltages, characterized in that, in order to increase reliability by providing the torque of the electric motor when operating in capacitor mode at break 5 two phases of the power supply network and reduction of dynamic overloads on the motor shaft while restoring the normal mode of power, a device was introduced; a switch; its relay; 0 one of the windings of which is connected to the output of the power source, and the other through a chain of parallel connected contacts of each of the three intermediate relays connected to with a common power supply source, the switching relay contact switch output is used to connect the appropriate stator winding of the electric motor to the end switch, and the corresponding closing contact of the relay is connected to the initial output of the stator winding of the subsequent phase of the electric motor, and the breakers of the switching cycles of the switching relay are interconnected into a star.