Contrary to the rectifier, the inverter converts the DC power into the communication power of the required frequency, and the 3-phase communication output can be obtained by turning on and off the 6 switching devices at the confirmed time. Take a voltage-type PWM inverter as an example to show the switching time and voltage waveform.
The control circuit is a circuit that supplies the control signal to the main circuit of the asynchronous motor (voltage and frequency can be adjusted), which consists of a "operation circuit" of frequency and voltage, a "voltage and current detection circuit" of the main circuit, a "speed detection circuit" of the motor, a "drive circuit" that expands the control signal of the operation circuit, and a "maintenance circuit" of the inverter and the motor.
(1) Calculation circuit: Compare the external speed, torque and other instructions with the current and voltage signals of the detection circuit to determine the output voltage and frequency of the inverter.
(2) Voltage and current detection circuit: detect voltage and current with the main loop potential barrier.
(3) Drive circuit: the circuit that drives the main circuit equipment. It is blocked from the control circuit to make the main circuit equipment on and off.
(4) Speed detection circuit: the signal of the speed detector (TG, PLG, etc.) installed on the shaft machine of the asynchronous motor is the speed signal, which is sent to the operation loop, and the motor can be made to work according to the command speed according to the instruction and operation.
(5) Maintenance circuit: detect the voltage, current, etc. of the main circuit, and prevent damage to the inverter and asynchronous motor when overload or overvoltage and other abnormalities occur
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Wiring method of the main circuit of the inverter - LS power generation
1. The power supply should be connected to the R, S, and T terminals of the VFD, and should not be connected to the VFD (U, V, W), otherwise the VFD will be damaged. It is necessary to clean up the trivial parts of the wire head after wiring, which may lead to abnormalities, failures, and failures, and it is necessary for the VFD to always be clean. When punching holes in the console, note that ...
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The selection principle of AC contactors - LS produces electricity
1. The voltage level of the AC contactor should be the same as the load, and the type of contactor should be suitable for the load.
2. The accounting current of the load should be less than or equal to the additional working current of the contactor.
The turn-on current of the contactor is greater than the starting current of the load, and the breaking current is greater than the load ...
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Inverter load test run step - LS power generation
1. Manually operate the work stop button of the inverter panel, investigate the work stop process of the motor and the display window of the inverter to see if there is any abnormal phenomenon.
2. If the inverter presents an overcurrent maintenance action during the process of starting P to abort the motor, ...
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LS power production contactors are used in this area
LS contactors are divided into AC contactors (voltage AC) and DC contactors (voltage DC), which are used in electricity, power distribution and consumption. Contactor in a broad sense refers to the electrical appliances that use the current flowing through the coil to generate a magnetic field and close the contact to control the load in industrial electricity.
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How to use the installation wiring of the LS inverter
1. Circuit wiring
(1) The input (R, S, T) and output (U, V, W) of the inverter cannot be connected incorrectly;
(2) Wire diameter selection
(1) The wiring of the power supply and the inverter and the wire diameter selection method of the motor of the same capacity are the same;
(2) The wiring between the inverter and the motor should consider the line electricity.
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Introduction to wiring problems - LS power generation
1. Wiring of fire emergency lighting
Generally, the flame retardant wire is used to wear the metal pipe and the thickness of the protective layer is ≥ 30mm.
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Debugging of basic parameters of inverter - LS power generation
There are many functional parameters of the inverter, and there are generally dozens or even hundreds of parameters for users to choose. In practice, it is not necessary to set and debug every parameter, and most of them only need to use the factory setting value. However, some parameters are very closely related to the application of practice, and some of them are still ...
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Common practical knowledge in the inverter industry - power inverter
The inverter is the power frequency power supply (50Hz or 60Hz) converted into various frequencies of AC power supply to achieve the variable speed operation of the motor equipment, by changing the motor power frequency to achieve speed adjustment, is an ideal high-efficiency, high-speed regulation means. Frequency converters are used in industrial production and residential ...
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The protection measures of the power generator inverter for the motor
The protection of the motor by the power converter mainly includes the following aspects: overvoltage protection, undervoltage protection, overcurrent protection, phase loss protection, inverter protection, overload protection, grounding protection, short circuit protection, overfrequency protection and stall protection.
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LS power inverter function
1. Soft up
The direct launch of the inverter motor has a serious impact on the power grid, and it will also have too high requirements for the capacity of the power grid, which is extremely unfavorable to the service life of equipment and power grid circuits. After the use of inverter to save energy, the use of inverter's speed regulation (V/F) function will make the starting current from a small ...
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Failure analysis of electromagnetic system of LS power production contactor
(1) The core noise is large: it is normal for the electromagnetic system to produce a slight humming sound during operation, if the sound is too loud or abnormal, it can be judged that the electromagnetic system has a problem, and there are three reasons:
(1) Poor contact between the armature and the core or tilting of the armature. After repeated collisions between the touch of the armature and the core, ...
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Parameter setting of LS power inverter
Control method: i.e. speed control, rotation control, PID control or other methods. After adopting the control method, it is generally necessary to carry out static or dynamic identification according to the control accuracy and requirements. Low operating frequency: that is, the small speed of the motor running, when the motor is running at low speed, its heat dissipation function ...
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The application of LS inverter in the grinding machine industry
First, the process requirements of the grinding machine:
The grinding machine is a kind of textile machinery, and its function is to polish the dyed cloth to improve its added value, which is an important process in the printing and dyeing process. The traditional drive mode is driven by a DC motor, which is linked with the lifting rod ...
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The five stages of mastery of PLC technology
One. Logical stage
The so-called logical stage is to be able to complete the general logical planning in the relay system, since it is a relay system, so the knowledge of power drag is the foundation of this stage. I personally summarize that the root of learning the relay system lies in the word "grab", the relay system ...
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DC reactor for inverter and design calculation - LS power generation
The DC reactor for the inverter is also called the flat wave reactor, which is connected in series in the DC bus (terminals P1 and P+). The main thing is to reduce the higher harmonic component of the input current and improve the power factor of the input power supply (to 0.95). This reactor can be used at the same time as the AC reactor, and the inverter has high power ...
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After the contactor is energized, the start button continuously engages and disconnects ?—— LS generates power
What is the reason why the contactor keeps engaging and disconnecting by pressing the start button after the AC contactor is energized?
In my personal opinion, most of the situation is caused by the wrong coil voltage of the replacement AC contactor, or the purchase of ...
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Introduction of LS AC motors
1. AC synchronous motor: that is, the rotor is composed of permanent magnet data, so after rolling, with the change of the stator rotation magnetic field of the motor, the rotor also changes the speed of the response frequency, and the rotor speed = stator speed, so it is called "synchronization".
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The working principle of LS PLC module
When LS PLC is put into operation, its operation process is generally divided into three stages, namely input sampling, user program fulfillment and output rewriting. The completion of these three phases is called a scan cycle. Throughout the operation, the PLC's CPU repeatedly performs the performance at a certain scanning speed on ...
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The cause of motor burnout caused by inverter - LS generates electricity
In fact, the problems of the motor are not the cause of the motor itself, most of them are caused by the non-standard debugging of the inverter or the wrong inverter motor when the inverter motor is used, etc., mainly due to the following situations:
1. Put the general motor ...
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LS power production PLC installation and wiring skills
The PLC should be kept away from strong disturbance sources such as electric welding machines, high-power silicon rectifiers and large-scale power equipment, and should not be installed in the same switch cabinet as high-voltage electrical appliances.
Power line, control line and PLC power line and I/O line should be separated from the wiring, barrier transformer and PLC and I/O should be selected ...
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