SU1264282A1 - Method of synchronizing synchronous electric motor - Google Patents

Abstract

The invention relates to electrical engineering and can be used in high-grade ore grinding mills. The aim of the invention is to improve the reliability of synchronization and reduce mechanical loads. A method for synchronizing a synchronous motor (DM) is to carry out (5h asynchronous start of a synchronous motor of a given magnitude. In this case, the winding.

Description

At the position of the LED rotor and the phase of the supply voltage, the indicated voltages are compared and upon reaching the result of the comparison of the predetermined value, a signal is produced, which is stored in the memory block 14. The failure at the output of the signal block 14 leads to the connection of O 3 to block 6 and the disconnection of O 3 from resistor 4 for

1264282

the presence of the element NOT 13. In this method, the synchronous excitation feed system itself chooses the most favorable timing mode for any engine load. it

- makes it possible to exclude the early

- excitation feed in O 3, reduce the number of unsuccessful starts, weaken

. resonant torsional vibrations. 1 silt

one

The invention relates to electrical engineering, as well as to the field of automatic control of synchronous motor starting, especially drives with ground conditions and drives containing elastic links, for example, synchronous electric motors of powerful grinding machines.

The aim of the invention is to increase the reliability of synchronization by maximizing the synchronizing capacity of the synchronous motor and reducing the mechanical loads in the drive.

The drawing shows a functional diagram of a synchronous motor synchronization device.

The device contains a synchronous motor 1 with a rotor position sensor 2 and with an excitation winding 3, in parallel with which the starting resistor 4 is connected via a switch 5 and the excitation unit 6 through a switch 7. The signal from the starting resistor 4 is fed to the input of the indicator 8 zero, one output of which is connected to block 9 frequency slip. The output of the latter is connected via the time delay unit 10 and the memory unit 11 to the input of the And 12 element. The second output of the zero indicator 8 is connected to the second input of the I 12 element. One of the inputs of the angle setting unit 13 is connected to the network. The remaining inputs of this block are connected to the rotor position sensor 2 and the output of the And 12 element. The angle setting block 13 is connected via the memory block 14 to the HE 15 element, the output of which is connected to the switch 5.

The second output of memory unit 14 is connected to switch 7.

The synchronization method of a synchronous electric motor is carried out as follows (for example, the operation of this device).

The asynchronous start of the synchronous motor 1 starts after connecting it to the AC network. In this case, the excitation winding 3 is closed to the starting resistor 4 by the switch 5 and disconnected from the excitation unit 6 by the switch 7.

The achievement of a given slip frequency (the beginning of the linear portion of the starting characteristic at small slip values) is determined by block 9 of the slip frequency over the duration of the time intervals between the output pulses of the indicator 8 zero, which are formed at each crossover current of the winding 3 zero crossing. When the duration of the interval exceeds the predetermined value (the slip frequency reaches the desired value), a signal appears at the output of the slip frequency block 9, which triggers the time delay block 10. With the help of the latter the time delay is carried out; proportional to electromechanical time constant

t M

SX

N 3-5;

J - reduced moment of inertia

drive;

 input slip; input moment;

Claims (1)

'Claim A synchronization method of a synchronous electric motor, in which the synchronous motor is accelerated to a predetermined sliding frequency, voltages are generated, which are proportional to the angular position of the rotor and the phase of the mains voltage, the indicated voltages are compared and, when the set value is compared, a constant voltage is applied to the excitation winding of the synchronous electric motor ; characterized by the fact that, in order to increase the reliability of synchronization, by maximizing the use of the synchronizing ability of a synchronous motor and reducing mechanical loads in the drive, upon reaching a given sliding frequency, a time delay of t = Ν · ^M _{m is} carried out where N is the number of proportionality <? t 3 to 5; J is the reduced moment of inertia of the drive; - input slip; M is the input moment corresponding to cZd, is the synchronous speed of rotation, after which they begin to perform the indicated * formation and subsequent comparison of voltages proportional to the angular position of the rotor and the phase of the mains voltage. VNIIIPI Order 5570/54 __________ Circulation 631 Subscription Custom polygr. ave, city of Uzhhorod, st. Project, 4