A lot more than 50% of the compression and pumping systems above 3 MW need a variable-speed drive. Often medium-voltage motors fed by frequency converters and parallel shaft gears are chosen. Others are using epicyclic gears with a hydrodynamic superimposition drive.
Taking benefit of the state of the art in electric motors and frequency converters, the driving system for the superimposition of the earth carrier is founded on a Long lasting Magnet Synchronous Superimposition (SI) engine and a dynamic Front-End Cycle Converter. Therefore – E stands for Electric.
This is a high-speed gear drive system incorporating components that allow the use of a low-cost constant-speed (electric) driver for a variable-speed application.
A lot more than 50% of the compression and pumping systems over 3 MW need a variable-speed drive. Frequently medium-voltage motors fed by frequency converters and parallel shaft gears are selected. Others are employing epicyclic gears with a hydrodynamic superimposition drive.
It started with hydraulic fluid couplings making slippage with results not much much better than the throttle.
The design of hydraulic clutches then improved and included a torque converter and a superimposed epicyclic drive.
Variable Frequency Drives (VFD) were developed and, at the same time, the expense of the shaft trains increased, therefore did efficiency. The problem of THD (Total Harmonic grid Distortion) rose and held VFD out of several applications.
Taking advantage of the state of the artwork in electric powered motors and frequency converters, the driving program for the superimposition of the earth carrier is founded on a Long term Magnet Synchronous Superimposition (SI) engine and a dynamic Front-End Cycle Converter. So – E means Electric.
This is a high-speed gear drive system incorporating elements that allow the use of a low-cost constant-speed (electric) driver for a variable-speed application.
All of the over plots were taken by analyzing the current to the electric motor. In a normal scenario, the vibration will be monitored and kept on a periodic basis. If the 360 Hz Variator Gearbox signal is present in the vibration spectrum, it is not normally of any concern. If, however, various other unexplained frequencies appear in the vibration spectra, then it might be advisable to have a look at both the current waveform and the existing spectrum. In the webpages that follow, some examples of problems found out in DC drives and motors are shown.”
It started with hydraulic fluid couplings making slippage with results not much much better than the throttle.
The look of hydraulic clutches then improved and included a torque converter and a superimposed epicyclic 
drive.
Variable Frequency Drives (VFD) were developed and, simultaneously, the cost of the shaft trains increased, and so did efficiency. The problem of THD (Total Harmonic grid Distortion) rose and held VFD out of many applications.