Where basically apply frequency converters Technical aspects of the use of converters.
Most drives uses asynchronous motor. At this stage of development of the electronics of the frequency Converter is almost the main unit to manage this type of machines, it is more convenient to use the inverter with PWM control to change the operation modes of the motor than anything else. All probably because the implementation of the control circuit is much simpler, and solutions can be much more, though it is not the plus and minus which creates some problems in the development of control systems for induction motors. I think after reading further you will understand everything yourself. Frequency converters first of all choose in power.
what questions to ask when selecting a frequency inverter The main thing is to understand that not only the basic choice is the power of the induction motor, but the nominal current of the Converter and the motor. Mainly in technical support (documentation on altiware and frequency converters) it is considered that the frequency Converter should operate in schemes a standard inclusion in a pair of four-pole induction motor, from here and is the nameplate power. In fact, everything is much more problematic and drive there are plenty of reasons not to adhere to what is written in the instructions and as a result there are many reasons that affect the growth of the current load of the actuator at the time of launch. In the basic model incorporating actuators reduce the current load from 600% to 100% of nominal at the start, it in General, but there is also a particular solution in which quite different figures appear. Another interesting aspect of the work which you need to pay attention, this reduced speed.
the Drive is pretty good adjusts the speed of rotation of the asynchronous motor in proportie:1, but you should consider the fact that if the inverter works for a long time on low speed, own cooling system may be insufficient, and if the inverter is in a poorly ventilated closet, it may happen accident. Therefore, in control cabinets, where installed frequency Converter should do the forced cooling operation, to put an additional fan.
the Next aspect electromagnetic compatibility
Frequency Converter it is a fairly complex device generating a wide range of high frequency harmonics and to their influence on the management process to reduce to a minimum when connecting the engine and the shielding of the cable as possible in less long. Preferably such cable to separate from the main conduit or tray, to reduce crosstalk in the cable, crossing the channel at 90%. But still the best solution to locate the inverter as close as possible to the asynchronous motor, and the control circuit, display them in a convenient place.
there Are cases when the production of primary input lost and washing is performed from ABP. Therefore, you should know that if used in the production of active drive, the backup power line can be significantly reduced, because the starting current of motors (main customer) will be reduced at least 4 times. If you eat on the ABP is not from another substation, and from the diesel generator, the gas savings will be substantial, and the power of the generator can be selected 4 times smaller than the existing one. Schematically always between Avrom and inverter put a contact group, which is under the control of relay outputs. This scheme will enable overvoltage inverter operative to automatically disconnect from the mains.
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