SU1264283A1 - Method and apparatus for automatic turn-in-turn self-starting of synchronous electric motors - Google Patents

Description

by the formation input of the cell (I) 3 memories. Input Erasing I 3 through a fault detector 8 faults connected to the output of the element AND 9. The output I 3 is connected to the first input of the element AND 5, the second input of which is connected to the output of the element NOT. The output of element 5 is connected to one of the inputs of unit 1. In the event of a breakdown in the external power supply, the electric motor is disconnected and the power supply is lost. At the output of sensor 2, a logical unit appears briefly. If by this time the units of the device, which control the excitation circuits of the LEDs, give a signal of health, then the logical unit will also appear at the output of the element I 4 for a short time. I 3 and block 6 go into excited

state, the countdown of the preset time delay begins by block 6. When the SD field quenching force chains are working properly before the end of the counting time, block 6 appears zero at the output of the HE 12 threshold element, the output of the HE 10 element is one, AND 5 is activated and conditions for self-start diabetes. Self-start is carried out only for that LED, whose reference time does not exceed 0.5-2 seconds, depending on the power of the LED and its mode of operation. These operations make it possible to increase the efficiency of restoring the original mode in the event of short-term interruptions of external power supply. 2 sec. f-ly 1 ill.

The invention relates to electrical engineering, and to automation that performs self-starting and restarting. electric motors, which are preserved in operation after short-term disappearances or voltage drops, are necessary according to technological conditions, and simultaneous amo start of all electric motors cannot be carried out due to the limited power network of the electrical network node.

The purpose of the invention is to increase reliability and reduce the time for self-starting.

The drawing shows a block diagram of a device for automatically alternately self-starting synchronous motors.

The device for automatic sequential self-starting of synchronous electric motors contains a common or all electric motors unit 1 alternate self-starting and individual control channels for synchronous electric motors, each control channel consisting of a sensor 2 activating motor protection from power loss, memory cells 3 with two inputs information and erasing also two two-input elements And 4 and 5, the first in

The first element And 4 is connected to the output of the sensor 2 triggering protection, the output of the first element And 4 is connected to the information input of memory cell 3, the code of the latter is connected to the first input of the second element 5, and its output is connected to the corresponding input of the common control unit 1 by alternating self-starting . The motor control channels also contain a time delay unit 6, an input connected to the output of the first element 4, a driver 7 for fault signals 8, a third two-input element 9 and 9 an element NE 10 and a series connected motor excitation level sensor 11 and a threshold element 12, and the output the threshold element 12 is connected to the second input of the first 4 and third 9 elements And the input element NOT 10, the output of the latter is connected to the second input of the second element And 5, the output of the time block buckle is connected via a pulse shaper 7 to a first input of the third AND gate 9, and the output of the latter is connected via a switch 8 to the input fault erasing memory cells 3.

The operation of the device is as follows.

In normal operation, when the synchronous motor is turned on, the threshold element 12 is j c in the actuated state and there is a logical unit at its output. At the output of sensor 2, there is no signal (logical zero). The block 6 and the memory cell 3 are in the initial, unexcited state, while the output of the block 6 is one and the output of the cell 3 is zero. At the outputs of elements 7 and 5, the signal is also missing.15

In the event of violation of the external electrical supply (the disappearance or deep-seated voltage), the electric motors are disconnected, which have lost power from the special protection against the loss of the pit-20. At the output of sensor 2, a logical unit appears briefly. If by this time all the units of the device that control the excitation of the electric motor, give a signal 25 health, then the output of the element 4 also briefly appears logical unit. From this signal, a transition to the excited state of the memory cell 3 and the block 6 of the delayed time is made. The countdown of the specified time delay by block 6 begins.

If: Forcing fields of a synchronous motor are working properly, then until the end of the time,. In the case of counting, a block 6 appears at the output of the threshold element 12, the output of the element 10 is a logical unit, the matching circuit 5, i.e. conditions are created for the motor to self-start. Upon successful self-starting of the electric motor, the control channel circuit of the electric motor passes to the initial state and the memory cell 3 is zeroed. This operation is performed by the common self-start control unit 1.

Unit 6, after a predetermined time delay, returns to the initial state, and a logical unit appears at its output. The output of the imaging unit 7 also shows a short-term single signal. However, scheme 9 does not match. since by this time at the output of the threshold element 12, the signal is missing.

If, for any reason, for example, if a contact is lost in the control circuit of the motor field forcing, after the time delay of the block 6 has elapsed, the field of the synchronous motor is off, i.e. Since the threshold element 12 remains in the actuated state, the coincidence circuit 9 is triggered and a single pulse appears at its output. As a result, a malfunction indicator 8 is triggered, the memory cell 3 is zeroed out, and there will be no subsequent resolution to the self-starting of this motor.

Claims (2)

1. A method of automatically alternately self-starting synchronous motors, in which, after a brief power failure, the motors are turned off, their magnetic field is quenched, the magnitude and speed of the restoring voltage from the power supply side are measured, the measured voltage is compared with the specified settings and when the settings are exceeded alternately starting the motors in a predetermined sequence, characterized in that, in order to increase reliability and reduce after the motor is disconnected, the time of current or voltage decrease in the excitation winding of each synchronous motor to the magnitude of the set point calculated in advance from the condition of damping the magnetic field of the motor to a value that allows self-start is measured, and only those motors that do not exceed this time are allowed to self-start 0.5-2 seconds depending on the power of the electric motor and the mode of its operation. 2. Device for automatic alternate self-start synchronous. electric motors containing a sequential self-starting control unit common to all electric motors and individual control channels each of a synchronous electric motor, each control channel consisting of an electric motor protection response sensor, a memory cell with two information inputs and an Erase, as well as two two-input AND elements, the first input of the first element I is connected to the output of the protection operation sensor, the output of the first element I is connected to the information input of the power cell The latter is connected to the first input of the second element I, and its output to the corresponding input of the common control unit alternately self-apus, so that, in order to increase the reliability and decrease the self-start time, a time delay block is inserted into the motor control channels. The input is connected to the output of the first element AND, the pulse shaper, the fault indicator, the third two-input element AND, the element NOT connected in series a motor excitation level sensor and a threshold element, wherein the output of the threshold element is connected to the second inputs of the first and third elements and the input of the element NOT, the output of the latter is connected to the second input of the second AND gates, time delay unit output is connected through a pulse shaper to the first input of the third AND gate and the output of the latter is connected via a switch to the fault entry Erasing the memory cell.