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 selected. 
Others are employing epicyclic gears with a hydrodynamic superimposition drive.
Variator Gearbox Taking advantage of the state of the art in electric powered motors and frequency converters, the driving system for the superimposition of the earth carrier is based on a Long lasting Magnet Synchronous Superimposition (SI) electric motor and an Active Front-End Cycle Converter. So – E stands for Electric.
That 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.
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 selected. Others are employing epicyclic gears with a hydrodynamic superimposition drive.
It started with hydraulic fluid couplings generating slippage with results very little much better than the throttle.
The design of hydraulic clutches then improved and included a torque converter and a superimposed epicyclic drive.
Adjustable Frequency Drives (VFD) were developed and, simultaneously, the cost of the shaft trains improved, therefore did efficiency. The problem of THD (Total Harmonic grid Distortion) rose and held VFD out of many applications.
Taking advantage of the condition of the artwork in electric powered motors and frequency converters, the driving program for the superimposition of the planet carrier is based on a Long lasting Magnet Synchronous Superimposition (SI) electric motor and a dynamic Front-End Cycle Converter. Therefore – E stands for 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 existing to the electric motor. In a normal scenario, the vibration will become monitored and kept on a periodic basis. If the 360 Hz signal is present in the vibration spectrum, it isn’t normally of any concern. If, however, additional unexplained frequencies come in the vibration spectra, after that it might be advisable to have a look at both the current waveform and the existing spectrum. In the pages that follow, a few examples of problems uncovered in DC drives and motors are shown.”
It started with hydraulic fluid couplings making slippage with results very little much better than the throttle.
The design of hydraulic clutches then improved and included a torque converter and a superimposed epicyclic drive.
Adjustable Frequency Drives (VFD) were developed and, simultaneously, the price of the shaft trains increased, therefore did efficiency. The problem of THD (Total Harmonic grid Distortion) rose and held VFD out of several applications.