ZYB external lubrication slag pump high-voltage motor frequency conversion speed regulation transformation should pay attention to the problem First, the motor characteristics test and technical specification revision When a common motor is powered by frequency conversion, the voltage and current components of the inverter output will make the motor Increased losses, reduced efficiency, and increased temperatures. ZYB external lubrication slag pump high-voltage motor frequency conversion speed regulation transformation should pay attention to the problem First, the motor characteristics test and technical specification revision When a common motor is powered by frequency conversion, the voltage and current components of the inverter output will make the motor Increased losses, reduced efficiency, and increased temperatures. The increase in loss caused by the external lubrication residual oil pump is mainly manifested in the increase of copper loss, iron loss and additional loss of the stator and the rotor. Among them, the copper loss of the rotor is the most significant, because the asynchronous motor always rotates in a state where the slip is close to 1, so the copper loss of the rotor is very large. In the ordinary asynchronous motor, in order to improve the starting performance of the motor, the skin effect of the rotor increases the actual impedance, thereby increasing the copper consumption.
On the other hand, due to the distributed capacitance between the motor coils, when the higher harmonic voltage is input, the voltage between the coils is not uniform, and this long-term repeated action causes damage to a certain portion of the stator coil, thereby generating damage. The coil is aged, which is unacceptable in terms of the insulation structure of a conventional asynchronous motor.
In addition, the electromagnetic circuit of the motor cannot be absolutely symmetrical, so the harmonic components contained in the output power of the inverter will interact with the spatial harmonic components inherent in the electromagnetic circuit to form various electromagnetic pulsations. At the same time, the motor is easily mechanically resonated with the mechanical part of the motor due to the constant adjustment of the frequency, resulting in damage to the mechanical part of the motor.
Therefore, in the variable frequency speed regulation renovation project of the external lubrication residual oil pump, in order to avoid the above problems during the operation of the variable frequency speed control system, the technical design must consider technical cooperation with the motor manufacturer to carry out the speed regulation experiment on the relevant characteristics of the motor. Revise the technical specifications of the original motor.
Second, the power cable selection points and laying requirements Because the connection between the output end of the inverter and the motor is cable-attached, and there is capacitance to ground in each phase of the line, the capacitance current on the line is not equal during operation. If the cable is attached for a long distance and there is a high-order harmonic current in the line, once the single-phase grounding occurs, the arc extinguishing time ignited by the fault capacitor current is too long, and the external lubrication residual oil pump will cause the cable at this end to heat up, resulting in Non-faulty insulation.
Therefore, in the variable frequency speed regulation retrofit project, for the output power cable, considering the three-phase symmetry and shielding on the cable structure, the cable cross section is appropriately increased, and the laying length does not exceed the limit value (100m), if the original output power supply If the cable is unshielded or the cross-section has a flow allowance of less than 2, the power cable that meets the requirements should be replaced.
When laying the facility on site, separate the power cable from the control cable and signal cable to avoid interference with other signals caused by the magnetic field generated by the higher harmonics in the power cable.
Third, the basic requirements of the working environment of the inverter Because the inverter part of the high-voltage inverter uses high-voltage IGBT and other power devices, its on-off frequency is greater than 100HZ, and it is easy to form high-order harmonic current, so that the frequency conversion device will produce certain Heat. Generally, the exhaust fan is equipped with an exhaust fan at the top of the inverter cabinet, which discharges the heat inside the cabinet into the room, which causes the indoor temperature of the room to continuously rise, and finally affects the reliable operation of each device in the cabinet. Therefore, the external lubrication residual oil pump is generally installed in the frequency conversion speed control room in the engineering design of the oil plant. The indoor air conditioning facility must be installed in the room to control the indoor ambient temperature within the range required by the inverter, and the ventilation door and window are also provided. If necessary, use a special air duct for forced ventilation and cooling.
Fourth, the high-voltage power supply system export circuit breaker control technology to improve the high-voltage side of the transformer used in the frequency conversion device should be directly connected with the switchgear in the high-voltage system, but the protection range of the switchgear is only the short-circuit of the power supply line and the low-voltage side of the transformer, and the frequency conversion The failure of the device should be completed by the inverter's own detection and protection system.
When the inverter has a fault and a trip signal is issued, the circuit breaker should trip reliably. However, when the trip circuit is disconnected or the DC control power supply disappears inside the high-voltage switchgear of the ordinary circuit breaker, when the inverter happens to be faulty (requires the circuit breaker to trip), the trip coil has lost power, and the circuit breaker refuses to operate, thus causing the inverter The internal power device is damaged. Therefore, the circuit breaker with undervoltage trip coil is selected in the design. Once the trip circuit is disconnected or the control power supply disappears, the circuit breaker first automatically trips to protect the safety of the inverter equipment.
Http://news.chinawj.com.CN
Gabion mattresses are used for river bank and scour protection, channel linings for erosion control, and embankment stability. They are filled with rock at the project site to form flexible, permeable, monolithic structures to promote rapid growth of natural vegetation. The base section of the Gabion Mattress is divided into compartments and filled with stones at the project site. With lids secured, Gabion mattresses form flexible, permeable, monolithic structures.
Features:
Low maintenance.
Simple assembly and filling, no need for qualified labour.
Filling is available in direct proximity.
Foundation work not necessary, only a place surface on a sustainable ground is needed.
Reno Mattress support the natural bank vegetataion and integrates naturally in the surrounding landscape
Packaging Details
1. Nude package,compacted before packaging.
2. Plastic packaging outside and on the pallet.
3 .Customized.according to the customers' requirment.
Reno Mattress
Galvanized Reno Mattress Mesh,Gabion Mattress,Gabion Reno Mattress
Anping shengsen metal wire mesh products co,. ltd , https://www.apshengsen.com