1. The output of the inverter is controlled by PWM (pulse width modulation, similar to high-speed switching), so high-frequency leakage current will occur.
The PE points of the three transmission equipment of the inverter, the pre-power supply transformer and the motor must be connected together and then grounded consistently.
The inverter is a high-frequency square wave voltage output, because there is an equivalent capacitance between the internal coil of the motor and the motor housing, resulting in leakage current. If it is not grounded or is poorly grounded, there will be leakage.
The factors that affect the size of the leakage current are:
(1) The leakage current of the cable of the cable and the leakage current of the cable of the switch and filter. The leakage current of the cable length of the inverter and motor.
(2) Leakage current of the filter (including the inverter).
(3) The leakage current of the motor.
Some on-site inverters are used to control the motor, and there will be leakage problems, and the leakage voltage ranges from tens of volts to 200 volts. In view of this problem, the reasons for the occurrence of this phenomenon are analyzed as follows:
2. According to the functional block diagram of the inverter to control the operation of the motor, the three-phase power supply is rectified through the inverter rectifier bridge, and then sent to the inverter bridge (IGBT) through capacitor filtering, and then the operation of the motor is controlled by the three-phase alternating current with adjustable output frequency and voltage of the inverter bridge.
The alternating current with a difference of 120 degrees flows through the three-phase stator coil winding of the motor, and a rotating magnetic field is generated, so that the rotor of the motor automatically rotates under the effect of the rotating magnetic field of the stator winding.
A rotating magnetic field occurs when an electric current flows through the three-phase stator windings of the motor, and an electromotive force is induced in the motor housing according to the principle of electromagnetic induction. The size of this induced electromotive force depends on the switching frequency of the IGBT and C×DV/DT (which is related to the speed of the IGBT switching). If the induced electromotive force is large, then the person will feel the same as being shocked when he touches it. Theoretically, the higher the switching frequency of the IGBT, the higher the effective value of the induced electromotive force (i.e., the induced voltage) of the motor shell, and the higher the control accuracy and dynamic response of the inverter to the motor, and the greater the feeling of being electrocuted by the human body after touching; Conversely, the lower the switching frequency of the IGBT, the lower the effective value of the induced momentum (induced voltage) of the motor housing, and the less it feels like it will be charged after touching the body.
Because the asynchronous motor is running, the motor shell will have induced voltage (that is, the so-called leakage), so the motor manufacturer will install a grounding terminal in the junction box when the motor leaves the factory, so that the user can connect to the earth to eliminate its induced electromotive force (i.e., eliminate the induced leakage voltage) during the application, so as to solve the feeling of being electrocuted when the human body touches the motor.
When the power frequency runs the motor, the switching frequency of the power frequency is about 50HZ, which is very low, so there is almost no feeling of leakage under normal circumstances (unless the motor insulation is very poor). When the inverter is controlled, because its switching frequency is much higher than the power frequency, the motor shell will have a feeling of leakage when the inverter controls the motor to roll.
|
More on that
|
Schneider TRSS telemetry system solution
Schneider Electric provides safe, reliable, end-to-end telemetry solutions to help you meet the challenges of long-distance operations. With an outstanding reputation in the fields of appearance, manipulation and data collection, wireless communications, IT, and other industries and common sense, Schneider Electric telemetry system solutions can help ...
|
|
Pressure Reducing Valve in Instrumentation – Schneider
A kind of pressure reducing valve in instrumentation refers to a kind of equipment used to control the pressure value. Pressure reducing valves are usually used in water-related categories, because from the perspective of the transmission medium, the transmission medium of the equipment is mainly water, but we all know that water is a thing that will ...
|
|
The difference between an inverter and a servo drive – Schneider
In terms of frequency converters:
The abbreviated inverter can only regulate the speed of the communication motor, and the open-loop or closed-loop can be determined depending on the control method and the inverter, which is the traditional V/F control method. Now many of the frequency conversion has been set up by mathematical models, which will communicate electricity ...
|
|
Steps for wiring and installation of rotary encoders – Schneider
Rotary encoder to roll the output pulse, through the counting equipment to know its position (PLC) we usually use incremental encoders, the incremental encoder output pulse signal can be directly input to the PLC, the high-speed counter of the PLC to count its pulse signal, in order to obtain the ...
|
|
Precautions for Schneider motors when operating above 60Hz
When operating beyond 60Hz, the following precautions should be taken
(1) 1 Machinery and devices should be able to operate at this speed (mechanical strength, noise, oscillation, etc.).
(2) The motor enters the constant power output range, and its output ...
|
|
Schneider's method of improving the power factor of UPS power supplies
One. The significance of the progressive power factor.
1. Make full use of the ability of power equipment.
Each power supply unit has additional capacity, i.e. depending on the power. The total power output of the power supply equipment S, - part of the active power, the other part is the reactive power, the smaller the ...
|
|
Common analysis method for electrical control line faults - Schneider
1) Survey and research method. The investigation and research method is to understand the obvious problem phenomena through "seeing", "listening", "smelling", "touching" and "asking"; After visiting the operator, understand the cause of the failure; A common way to help find the fault point after asking others or consulting information ...
|
|
Schneider lamellar relays
Schneider RSL Thin Sheet Relay, as a member of the large family of ZelioRelay series relays, RSL Thin Plate Relays will be committed to saving users space and time in the device, and improving the stability of the system.
Schneider Electric Vice President of China, Head of Industrial Division, Xiu De...
|
|
Schneider automatic control instrument construction content and procedures
1. Construction preparation. Including the preparation of operating conditions (construction skills documents and detailed design documents), construction organization design, equipment list, data budget, and list of machined parts;
2. Cooperate with civil engineering majors to do a good job of pre-embedding and reserving work;
3. Cooperate with process equipment, ...
|
|
How to choose the right inverter for the motor?
The inverter is an electric transmission element that is used in frequency conversion skills and microelectronics skills to control and communicate with the motor by changing the frequency and fluctuation of the power supply of the motor.
The birth of the inverter cabinet originated from the communication motor ...
|
|
Instrumentation mechanical equipment system - Schneider
1. Power system:
The wire and cable products selected in the power system mainly include overhead bare wires, busbars (busbars), power cables (plastic cables, oil-paper power cables (fundamentally replaced by plastic power cables), rubber cables, overhead insulated cables), branch cables (replacing part of the busbars), ...
|
|
Schneider improves plant performance with automated control
1. Engineering planning one by oneWith data at their fingertips and intelligent and sensitive functions, engineers can easily plan and test equipment, improve process availability, and easily complete system integration together – ultimately reducing the planning time by up to 25%.
...
|
|
Schneider relay model introduction
RM4 Series Control Relay (Three-phase Power Control)
RM4 series voltage steerable relays
RM4 current operated relay
RM4 level control relay
RM17 three-phase power controller
RM35 3-phase power control relay
RM17 Voltage Steerable Relay ...
|
|
The difference between vector and general use of inverter - Schneider
1. The control accuracy of the vector type is higher than that of the general-purpose type.
2. The vector type has a large output torque at low speed, which can make the motor get a larger starting torque, which is suitable for application in the occasion of heavy load starting, such as: high-power long belt, hoist, etc. If used in some of the more common fields ...
|
|
Schneider electrical circuit control fault range
In general, depending on the phenomenon of equipment problems, the scope of the problem can be roughly confirmed as follows:
1) All button functions fail, and there is a high possibility of power supply or fuse problems.
2) Some buttons are invalid, and some of the buttons are functioning normally ...
|
|
Inverter power settings, waveform test issues
1. After the inverter is repaired, the power number demand is corrected, don't forget
Generally, an inverter corresponds to a power number (also known as the number of horsepower), for example, a 75 kilowatt inverter is set under heavy load, and 100 kilowatts is set under light load. In this way, the customer will not use it to present ...
|
|
Is there a restriction on the installation direction when Schneider installs the inverter?
It should be basically stored in the plate, the problem is that the plate with a fully enclosed structure is large in size, takes up a lot of space, and the cost is higher. This can be done by:
(1) The planning of the disc should be based on the heat dissipation required by the actual device;
(2) Profit ...
|
|
Schneider inverter simple question
1. How to complete the control of ATV38 and ATV58 through the operation panel?
First, in the control menu, set "LCC" to "YES" (panel operation); Enter the "LFR" parameter in the adjustment menu, press the up and down keys to adjust the given value, and complete the control of the inverter.
...
|
|
Precautions for the installation of low-voltage electrical appliances - Schneider
1. Low-voltage electrical appliances should be equipped in a place without violent vibration, and should have an appropriate height from the ground. It is necessary to connect the power cord such as the knife switch and the load switch to the fixed contact, and it is forbidden to hang the power cord on the knife switch.
2. Low-voltage ...
|
|
The difference between high voltage and low voltage of Schneider inverter
1. What is the difference between high-voltage inverter and low-voltage inverter?
Frequency converters can be broadly divided into two categories: high-voltage frequency converters and low-voltage frequency converters.
In terms of use, the applicable objects are different, and the high-voltage motor is the same from the principle of speed regulation. From the topology ...
|
|
Contact
working hours
