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7 months back I was involved in a harmonics evaluation study at Budweiser. This was one of many I've participated in over the past 20 years, basically because in facilities like this not one or two, but hundreds of variable speed drives (VSD) are in use. They are but one of many plants using variable speed drives for nearly all of their production controls. Capacitive reactance is inescapable when capacitors are in use in a circuit, as is inductive reactance when motors are operating, or any other component incorporating electro-magnetic coils. This reactance is the issue when dealing with harmonics, as can be the power supply to the facility itself. All variable speed drives employ capacitors.
Most of variable speed drives are applying on high temperature fans, kiln head coal mill fans, kiln head surplus fans, raw mill circulating fans and so on. Two production lines with daily productivity 5000T in the Cement factory. By variable speed drive, the two production lines achieve ideal energy-saving effect. Nowadays variable speed drive technology is more mature and failure rate is lower. It is an ideal equipment for energy-saving reconstruction in cement industry.
The good of PLC is it work in a hazard environment and robust. We have
Omron CQM1 for DI water plant, after a big flooding in Thailand ( stay
under water for more than 2 months) after we clean dry and bake ( remove
every single board into basket) and re-assembly it back and upload a
backup ladder program, it work wonderfully.
Clean the variable frequency drive heatsink and check or replace the fans. I like new fans every five years. I also double check the drives installation. This is a good opportunity to make corrections to the install like conduits or cable routing. Check the connections but don't give the terminals a crank. They should be re-tightened after a couple of weeks after the commissioning. After that giving them a crank every preventive maintenance is asking for a broken terminal. At our facility we have drive that have run for 20 years with preventive maintenance performed every six months.
Over-sizing the machine as an alternative. It did not work in my motors as the design had brazed rotors. Rotor losses will increase due to over-sizing and heat accumulated faster than the reduction in the starting time. This is bad during commissioning when frequent successive starts are taken. The heat generated in the rotor is normally the limiting factor. Variable speed drive is a good solution, but not economical in many cases.
Variable speed drive application in purification system optimizes the system performance, improves purification effect, reduces power consumption greatly. According to related statistic, flue gas
consumption reduces 19m3/t. Total power consumption reduces 137000kW.h per month.
What about the frequency of the small amount of the power which back to the network its depend on the speed of the rotor and number of poles f=60/N.P? In another word assume I have AC generator give AC power source what is the voltage and frequency of this power? How to calculate it?
Variable speed drive is a new power inverter and it has applied in industry maturely. It not only starts motor easily with lots of protections but also saves energy. So it is very necessary to utilize variable speed drive to improve safety and automatization. Variable speed drive realizes soft start/stop and saves energy. It adjusts speed according to air flow demand in lane easily with ideal effect. China has many coal mines, medium voltage variable speed drive application must be widely in this field.
For variable speed drives, there are two power semiconductor technologies employed: bridge rectifier and the output stage.
The bridge rectifier is made up of power rectifiers which are connected directly to the supply and drive a capacitor bank, either directly or via inductors. By design, then, the rectifier of the variable speed drive is less likely to be damaged by a short circuit on the output or in the motor.
A more efficient variable speed drive for motors could help the ubiquitous, energy-sucking devices make another leap in energy efficiency. The problem is that most motors are oversized because of high torque requirements that are only needed for a small portion of the motor’s use.
In electronic design, they use "time simulation" (or "dynamic simulation"), which is an off-line calculation of how a system might respond to various inputs. The inputs are mathematical in this case, and the simulation need not run in real-time. Indeed, in the old days it might take days of calculation to get the result, even if the real process was very brief. In electronics, these are termed "SPICE models". My work long ago with CSMP and analog computers was similar. Calculating physics events like nuclear or chemical reactions, or weather models is similar.
The SCADA (Supervisory Control And Data Acquisition) would also be a HMI (Human Machine Interface) and if the HMI system had the additional data acquisition which most are capable of then it would also be SCADA. The advent of the Windows data exchange and client - server model has blurred the picture to the point this this question is bordering on being trivial as the differences are so small. The same questions could be asked or made about the differences in DCS and SCADA and HMI.
VSD blog: A deep observation of automation control industry, especially in AC motor variable speed drive for industrial motor controls. Hot Tags
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7 months back I was involved in a harmonics evaluation study at Budweiser. This was one of many I've participated in over the past 20 years, basically because in facilities like ...
Most of variable speed drives are applying on high temperature fans, kiln head coal mill fans, kiln head surplus fans, raw mill circulating fans and so on. Two production lines ...
Variable speed drive application in purification system optimizes the system performance, improves purification effect, reduces power consumption greatly. According to related ...
The motor power factor does not make a big difference other than giving an idea of loading. In regards to the variable speed drive fixing power factor everyone is mostly correct. ...
A soft starter is a basic device which will ramp up the speed of your motor to full speed over a preset time, easing mechanical stress and also easing the high inrush currents ...
What's New
Variable Speed Drive Harmonics
Variable speed drive energy saving in cement industry
PLC and DAQ
Is it good to do preventive maintenance for variable speed drives
Does motor starts number affect motor life?
Variable speed drive for ID Fans in mining industry
Regenerative power frequency back to line power
Variable speed drive for axial-flow fans
Variable speed drive energy saving in cement industry
PLC and DAQ
Is it good to do preventive maintenance for variable speed drives
Does motor starts number affect motor life?
Variable speed drive for ID Fans in mining industry
Regenerative power frequency back to line power
Variable speed drive for axial-flow fans
