1. Step-by-step decreasing method
The so-called gradual reduction method is to gradually reduce the scale of the problem through the analysis of the problem phenomenon and the identification of measurement parameters, and finally implement it to the specific circuit or component that causes the problem. In essence, it is a process of discriminating of certainty, negation, re-negation, re-negation, and finally certainty (discrimination).
For example, after a VFD is powered on, it is found that the operation panel is not visible. First of all, it is necessary to determine that there is no DC power supply (the DC power supply voltage can be measured with a multimeter). After further inspection, it was found that the high-voltage indicator light was on (further admitted after measuring the PN voltage), which denied the fault of the high-voltage circuit of the main circuit, and there must be a problem with the switching power supply supplying power supply to the operation panel. If the AC voltage of the power supply is normal, there is no DC output, and there is no short circuit, it can be concluded that the rectifier tube of the power supply circuit is damaged. This example, uses a typical step-by-step approach to shrinking. The whole process is to go through analysis and parameter measurement, and several rounds of discrimination, certainty, and negation, and finally confirm the damage of the rectifier.
2. Follow the vine to touch the melon
According to the operating principle of "VFD", the so-called "follow the vine and touch the melon" method is a method that gradually deepens along the fault site and along the signal path to the fault occurrence point and finally finds the fault location.
For example, the VFD output voltage is unbalanced in three phases. This failure is clearly formed by two possibilities. One possibility is that at least one of the six units of the inverter bridge is damaged (open circuit), and the other possibility is that at least one of the six sets of drive signals is damaged. Assuming that an inverter unit does not have a driving signal, it is possible to further confirm the location of the drive circuit fault, and you can find it by following the vine. For this specific example, you can check from top to bottom, that is, from the source of the driving signal, that is, from the output of the CPU.
When the CPU outputs a signal, check whether there is a signal at the input of the optocoupler. If there is no signal, the input of the CPU and optocoupler is disconnected. If there is a signal, check the output of the optocoupler to see if there is a signal in the optocoupler output. If there is no signal, the optocoupler is damaged. If there is a signal, look again at the inputs and outputs of the amplifier circuit. If there is a signal in the input and no signal in the output, it is clear that the fault is caused by damage to the enlargement circuit or enlargement tube or related components. Then further implementation will be simpler.
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Senlan inverter selection points
1. Select the inverter according to the load characteristics, such as the load is constant torque load, you can choose Siemens MM440 inverter, ABB ACS800 series inverter, etc.; If the load is a fan or pump load, you can choose Siemens MM430 inverter, ABB ACS510 series inverter, etc.
2、 ...
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The manufacturing standard of Sunland inverter cabinet
Planning specifications: The planning of inverter cabinets should conform to relevant national norms and industry norms, such as GB/T15576-2018 "Low-voltage Distribution Cabinet", GB7251.1-2017 "Low-voltage Complete Switchgear and Control Equipment", etc.
Material specifications: The materials of the control cabinet should conform to the relevant codes and regulations.
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Inverter braking resistance connection method - Senlan inverter
If the drive has a built-in braking unit and additional braking resistors, it is important to pay attention to the correct wiring of the braking resistors. The braking resistor should be connected between the P terminal and the DB terminal, but not between the P terminal and the N terminal, otherwise the three-phase rectifier bridge will operate at full load when it is not running, resulting in the equipment can not be ...
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The difference between "braking" and "parking" of the inverter - Senlan
There are two ways to park a drive.
One way is called "free parking". It is to quickly "power off" the motor, so that the motor can slide and park by its own inertia force (OFF2 parking);
The other way is called "braking parking". So this "brake parking ...
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Effect of inrush current on inverter - Senlan
In the process of repairing the inverter, we can find that because of the back electromotive force in the stator winding, the electromotive force in the synchronous generator state and the self-induced electromotive force in the self-loop rotor, the current impact will inevitably have a negative impact on the motor, the inverter (Variable-frequency ...
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The servo motor is connected to the wrong wire and causes a problem - Senlan
If the three power cables of the servo motor (SM) are not connected correctly, there may be no alarm in the static state. But as soon as the motor is operated manually or actively, the motor jumps off or starts to flutter, such as jumping when the speed is added too high, the system will issue generalized faults, etc.
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The choice of inverter braking resistor - hope Senlan
In addition to the limitation of the maximum promised current of the special energy consumption braking unit of the inverter, the selection of the braking resistor has no clear correspondence with the braking unit, and its resistance value is mainly selected according to the size of the required braking torque.
Power...
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At the physical level, the stable operation of the inverter is guaranteed-Senlan inverter
For the most popular electrical control equipment inverter (Variable-frequency Drive, VFD), as a precision electronic industrial control equipment, in order to run smoothly for a long time, we, as professional and technical personnel, need to be on the VFD device or before the operation.
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The correct wiring of the rail power supply
The rail-rail power supply is a kind of switching power supply that is installed through the rail-type device, which is mainly used to monitor the voltage, current, temperature and other different aspects of the equipment, so that it can play a good maintenance effect. This switching power supply has a variety of different characteristics such as small size and light weight, ...
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The connection method of the shielded wire adheres to the principle - Senlan inverter
1. The shield wire should be as close as possible to the low potential end, which can be understood in this way, generally we think that the ground potential is "0", and in reality, if there are two grounding terminals, there will be a potential difference between the two grounding terminals at a certain time, and there will be a current between the two wires, which is also a kind of agitation.
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About the basic selection of Hope Sunland inverter
It is hoped that Sunland low-voltage inverter can be divided into four series:
1.HG1000 high-performance light-load intelligent inverter, the most cost-effective, the new series is widely used in medicine, food, packaging, cable, printing and dyeing, washing, centrifuge ...
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What are the peripheral equipment for inverter selection - Senlan inverter
After the inverter selection is completed, it is necessary to consider whether other peripheral equipment needs to be equipped according to the actual situation of the site. The peripheral equipment for frequency converter selection mainly includes circuit breakers, reactors, contactors, braking resistors, etc.
1. Circuit breaker
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Inverter load type - Sunland inverter
(1). Constant torque load
Different speeds, load resistance and torque base are stable. The output power is directly proportional to the rotational speed. Such as belt conveyors.
(2). Constant power load
Different speeds, stable load power base ...
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Introduction to the classification method of inverter maintenance faults
1. How to distinguish between heavy faults and light faults
According to the occurrence time of inverter faults, we can divide the types of faults into two categories: sudden faults and intermittent faults:
(1) The sudden fault of inverter repair refers to the failure of the equipment when it is running, without warning.
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Inverter remote control wiring method - Senlan
1. Connect X (switching input) drive terminal to control the inverter start-stop/forward and reverse rotation;
2. Connect to the AI (analog input) terminal to control the frequency of the inverter (perhaps made into PID closed-loop control active conditioning frequency)
3. Other DO (switching output) is used for transmission ...
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Selection and capacity matching of inverter - Senlan
1. Select the inverter according to the load characteristics
Second, when selecting the inverter, the actual motor current value should be used as the basis for the selection of the inverter, and the extra power of the motor can only be used as a reference. Secondly, it should be fully considered that the output of the inverter contains higher harmonics, which will form the power factor of the motor.
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The inverter's requirements for the surrounding environment - Senlan
1) Operating temperature: The inverter is a high-power electronic component, which is simply affected by the operating temperature, and the general temperature requirement is 0 - 55. However, in order to ensure the safety and reliability of the operation, it is necessary to consider freeing up space when using, and it is best to control it below 40. The inverter generally requires the device to operate ...
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Industrial control circuit board capacitor damage fault characteristics and maintenance - Senlan
Capacitor damage is the highest problem in electronic devices, especially electrolytic capacitors.
Capacitor damage is manifested in: 1. Capacity becomes smaller, 2. Capacity is completely lost, 3. Leakage, 4. Short circuit.
Electricity...
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Hope Sunland grid-connected PV inverter
Grid-connected photovoltaic inverter is one of the core components of solar photovoltaic power generation system, the main types are: central inverter, modular inverter, micro inverter, DC ...
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Sunland inverter braking resistor connection
Assuming that the inverter has a built-in braking unit and additional braking resistors, it is important to pay attention to the correct wiring of the braking resistors. The braking resistor should be connected between the P terminal and the DB terminal, but not between the P terminal and the N terminal, otherwise the three-phase rectifier bridge will operate at full load when it is not working, resulting in the equipment being unable to ...
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