1. The transformer is grounded twice
It refers to the grounding of the S2 terminal of the current transformer or the ground of the n terminal of the voltage transformer. As long as the single point is grounded, because the transformer is blocked between the second and the first, before grounding, the secondary winding has no potential contact with the earth, and after grounding, the transformer will not form a loop with the earth, and the current will not flow to the ground during normal operation. When the insulation between the primary winding and the secondary winding is damaged, the primary high voltage is connected to the secondary circuit, and the primary high voltage has a fixed potential connection with the earth, and the current will flow to the earth, and the secondary voltage of the transformer will be clamped to the ground voltage to ensure the secondary appearance and personal safety.
Second, the grounding reason of the secondary side of the voltage transformer and the current transformer
1. There should be a grounding point on the secondary side of the voltage transformer, which is mainly for safety considerations. When the insulation between the windings of the primary and secondary side is broken down by the high voltage, the high voltage on the primary side will be channeled to the secondary side, and the grounding of the secondary side can ensure the safety of personnel and equipment. In addition, it is possible to supply phase voltage to the insulation monitoring equipment after grounding.
2. There should be a little grounding on the secondary side of the current transformer. Because the primary side of the high-voltage current transformer is high-voltage, when the high-voltage breakdown occurs between the first and second coils due to insulation damage, it will cause the high-voltage to flow into the low-voltage. If the secondary coil is grounded, the high voltage will be introduced into the ground, so that the secondary coil adheres to the ground potential, so as to ensure the safety of personnel and equipment.
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Interference phenomenon of LS power inverter
1. As soon as the inverter of the heat exchange station is opened, the pressure transmitter jumps randomly;
2. In the water supply controlled by the inverter, the pressure transformer is used as a signal to collect the pressure, and the pressure transformer is disturbed by the inverter;
3. When the inverter starts the motor, the voltage converter signal is unstable and beats violently;
4. Pressure transformer (4-20 ...
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Fatal failure of LS power terminal block
From the point of view of application, the function that should be reached is: it is necessary to conduct the local area where the touch part should be conducted, and the touch is reliable. If the insulating part should not be conducted, it is necessary to insulate it firmly. There are three common fatal problems in terminal blocks:
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LS takes you to understand the inverter in the inverter
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.
Control circuit ...
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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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The main part of LS power inverter is composed
The inverter circuit is the first part of the inverter
The function of the DC central circuit is to smooth the output of the rectifier circuit to ensure that the inverter circuit and the control power supply can obtain a DC power supply with higher quality. When the rectifier circuit is the voltage flow of the central circuit, the primary component is the electrolysis of Darongtong ...
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Why can't the inverter be equipped with a leakage protector - power generation
When using an inverter, a leakage maintainer must not be used. This is a major principle of the use of frequency converters.
Some users choose the corresponding leakage maintainer for the inverter when using the inverter. *The result is: the inverter moves together ...
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Whether the C-type circuit breaker is suitable for the motor circuit - power generation
Type C micro-break is used for general circuits, such as lighting circuits; D-type circuit breakers are used in power circuits such as electric motors, so can C-type micro-breakers be used in motor circuits?
Differences between C-type and D-type discontinuity:
C-type micro-disconnect: with ...
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Introduction to the output frequency of the inverter - LS power generation
1. Maximum frequency fmax, reference frequency fN and reference voltage UN
2. The upper frequency fH and the lower frequency fL
The output frequency of the inverter is limited to the upper and lower limit frequencies to prevent errors in the event of misoperation.
3. Frequency of activation
When the signal ON is activated, the ON ...
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The basic component of the inverter is LS power generation
The inverter is usually divided into 4 parts: the rectifier unit, the high-capacity capacitor, the inverter and the controller.
Rectifier unit: converts alternating current with a fixed operating frequency into direct current.
High Capacitance: Stores converted electrical energy.
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Precautions for powering on the inverter after the LS power production holiday
1. During the holiday, low temperature can easily cause the equipment to be damp, check whether the electrical equipment is dry, whether there is moisture and condensation;
2. Check whether the grounding wire is loose and whether the cable is damaged by rodents and insects;
3. Sort out the dust and oil stains, and inverter ...
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Basic introduction to transistors - LS produces electricity
A transistor is a solid-state semiconductor device with a variety of functions such as detection, rectification, amplification, switching, voltage regulation, and signal modulation. A transistor is a variable current switch that can manipulate the output current based on the input voltage. Unlike general mechanical switches (e.g. Relay, swit...)
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Summer maintenance and maintenance of inverter method - LS power generation
1. Check the running status of the inverter, whether the voltage and current value during operation are within the normal range.
2. Carefully monitor and record the ambient temperature of the frequency conversion chamber, which is generally between -5 °C and 40 °C. The temperature rise of the phase-shifting transformer should not exceed 130°C.
3. Prevent ...
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The power of LS power inverter is selected
The relationship curve between the load rate β and the power η of the inverter can be seen: when β = 50%, η = 94%; When β = 100%, η = 96%. Although the β has doubled, the η change is only 2%, but it is also considerable for medium to high power (a few hundred kilowatts to several thousand kilowatts) electric motors. The system power is equal to the inverter power ...
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A common fatal form of failure of the terminal block - LS power generation
1. Poor touch
The metal conductor inside the terminal block is the core part of the terminal, which transmits the voltage, current or signal from the external wire or cable to the touch piece corresponding to the connector it matches. Therefore, it is necessary for the touch parts to have excellent structure, stable and reliable touch firmness.
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LS power converter interference phenomenon
1. As soon as the inverter of the heat exchange station is opened, the pressure transmitter jumps randomly;
2. Use the inverter to control the water supply, the pressure transformer is used as the signal to collect the pressure, and the pressure transformer is disturbed by the inverter;
3. When the inverter starts the motor, the voltage converter signal is unstable and beats violently;
4. Pressure transformer (4-20 ...
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LS has reached agreements with Doosan and Hanwha in Korea on a business model for vacuum power generation
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Application of servo motor - LS power generation
Quick to use:
There are three cables necessary for the operation of the motor: power cable; Motor power line, motor encoder line.
Control line interface X5:
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Precautions for the peripheral configuration of the inverter - LS generates electricity
(1) When the inverter is connected to the power grid of large-capacity power transformer (more than 500kVA), perhaps the same power transformer is connected with a thyristor converter without using a commutation reactor, or when there is a switching capacitor bank for power improvement in the same power grid, an AC reactor or DC reactor should be equipped.
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Precautions for the selection of peripheral equipment for LS power inverter
The peripheral equipment of the inverter mainly includes cables, contactors, air switches, reactors, filters, braking resistors, etc. Whether the selection of the peripheral equipment of the inverter is correct and suitable also directly affects the normal operation of the inverter and the service life of the inverter.
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