SU1582328A1 - Two-motor ac electric drive - Google Patents

Abstract

The invention relates to electrical engineering and can be used in an electric drive apparatus with a mixing device. The purpose of the invention is to reduce energy consumption by selectively operating the drive at a variable load. The electric drive uses two current relays 8 and 16 with coils and disconnecting contacts 17 and 18, respectively, configured one to release at a load current less than the sum of the rated current of the engine 1 and the no-load current of the electric motor 2, the other to operate at a load current greater than the nominal motor current 1. At start-up, two electric motors operate, after the load current decreases to the value of the current triggered by the first current relay, the electric motor 2 is turned off, the current relay 8 is turned off, and the current relay 16 is connected from the coil minutes and therefore controls the load current of the motor 1. When the load current increases with the relay coil 16, which leads to the inclusion of the engine 2 and connecting current relay 8 to the coil in the drive control circuit. This makes it possible to eliminate the "false" actuation of the electric motor 2 and, depending on the drive load, turn on the required number of engines. 1 il.

Description

The invention relates to electrical engineering and can be used in an electric drive apparatus with a mixing device, in particular in a twin-engine electric drive common industrial devices with a stirrer.

The purpose of the invention is to reduce energy consumption due to selective operation of the electric drive at variable load.

The drawing shows the scheme predla 1Chem electric.

 The electric drive contains three-phase asynchronous electric motors 1 and 2 with a common load on the shafts, a first contactor with a coil 3 with three power closing A and one locking 5 contact, a second contactor with a coil 6 with three power closing contacts 7, the first current relay with coil 8 and current sensor 9 for switching on one of the phases of the power supply. The current sensor 9 is connected to the first output of the first output of the coil 8 of the first rela current. The stator windings of each of the electric motors 1 and 2 through the respective power closing contacts 4 and 7 of the contactors are integrated and provided with clamps for connection to the phases of the power source. The first pin of the button 10 Stop is provided with a clip for connecting the power supply to one phase, and the second pin is connected to the first pin of the button 11 shunted by the make contact 5 of the first contactor. The electric drive also includes a time relay with a coil 12 and a closing contact 13 and an intermediate relay with a coil 14 and an opening contact 15. The first terminals of coils 3, 6, 12 and 14, respectively, of the first and second contactors, the time relay and the intermediate relay are combined and equipped clamp to connect to another phase of the power supply. The second output of button 11 Start is connected to the second output of coil 3 of the first contactor, through the disconnecting contact 15 of the intermediate relay to the second output of coil 6 of the second contactor and through the closing contact 13 of the time relay to the second output of coil 14 of the intermediate relay. The drive also includes a second current relay with coil 16 and disconnecting

„5 0 5

0

five

0

five

contact 17. The first current relay is provided with a disconnecting contact 18, the second contactor with a closing contact 19, the time relay with a disconnecting contact 20, and an intermediate relay with a closing contact 21, the first terminal of which is connected to the first output terminal of the coil 16 of the second current relay. The second output of the coil 16 of the second relay is connected to the first output of the coil 8 of the first current relay, the second output of which is connected to the second output of the closing contact 21 of the intermediate relay and the second output of the current sensor 9 via the opening contact 20 of the time relay that is shunted by the second contact 19 of the second contactor. The second output of the coil 12 of the time relay is connected in series with the opening contacts 17 and 18 of the first and second current relays connected to the second output of the Start button.

The drive works as follows.

When you press the Start button 11, the coil 3 and 6 contactors and the coil 12 are turned on. Pin 5 of the first contactor shunts the Start button 11. From the starting current, the first current relay is activated and breaks the power supply circuit of the coil 12 of the time relay. At the end of the start-up period, the first current relay, configured to release when the load current is less than the sum of the rated current of the first electric motor 1 and the no-load current of the second electric motor 2, closes contact 18 in the power supply circuit of the coil 12 time relay, which delayed its contact

13 closes the coil power circuit

14 intermediate relay, and contact 20 prepares to disconnect the first current relay. The intermediate relay, having operated, with its contact 21 turns on the second current relay, and by contact 15 breaks the power supply circuit of coil-6 of the second contactor. Electric motor

2 is disconnected from the network. At the same time, the contact 19 disconnects the first current reverse from operation, and the second current relay, configured to operate at a load current greater than the rated current of the first electric motor, is put into operation. With an increase in the load current above the set, the second current relay is activated, and by its contact 17 it breaks the power supply circuit of the relay

the time that the contact 20 connects the first current relay and opens the power supply circuit of the coil 14 of the intermediate relay. Contact 21 opens and shuts down the second current relay, through contact 15 the coil 6 of the second contactor is connected. In this case, the first current relay again controls the decrease in the load current of the first motor.

Thus, in the proposed electric drive, alternating switching of the first and second currents is provided according to its own signals, which allows to achieve energy savings, since the number of working electric motors depends on the load on their shaft.

Claims (1)

Formula invented and AC twin-motor electric drive containing two three-phase asynchronous electric motors with a total load on the shafts, a first contactor with a coil with closing and three power closing contacts, a second contactor with a coil with three power closing contacts, the first current relay with a coil, a current sensor for switching on one of the phases of the power source, the first output is connected to the first output coil of the first relay current, the stator windings of each three-phase asynchronous electric motor through the corresponding power closing contacts of the first and second contactors are integrated and provided with terminals for connection to the source phases and power, the Stop button, which first terminal is provided with a clamp for connection to a single phase power source, a second terminal keys 0 r 0 The stop is connected to the first output of the Start button, bypassing the closing contact of the first contactor, the time relay with the coil and the closing contact, the intermediate relay with the coil and the opening contact, the first leads of the coils of the first and second contactors respectively, the time relay and the intermediate relay are combined and provided with a clip for connecting to a different phase of the power supply, the second output of the Start button is connected to the second output of the coil of the first contactor, through the disconnecting contact of the intermediate relay to the second output of the coil the second contactor and through the closing contact of the time relay - with the second output of the coil of the intermediate relay, characterized in that, in order to reduce energy consumption due to selective operation of the electric drive at variable load, a second current relay with a coil and a break contact is inserted into it, the first current relay is equipped the opening contact, the second contactor is provided with a closing contact, the time relay is equipped with the opening 0 contact, the intermediate relay is equipped with the closing contact, the first terminal of which is connected to the first One coil of the second current relay, the second output of which is connected to the first output of the coil of the first current relay, the second output of which is disconnected from the time relay contact, bridged by the closing contact of the second contactor, connected to the second output of the closing contact of the intermediate relay and the second output of the current sensor the time relay is connected in series through the break contacts of the first and second current relay to five five 0 five the second output of the Start button.