A lot more than 50% of the compression and pumping systems above 3 MW require a variable-speed drive. Often medium-voltage motors fed by frequency converters and parallel shaft gears are chosen. Others are employing epicyclic gears with a hydrodynamic superimposition drive.
Variable Speed Gearbox Taking advantage of the condition 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 lasting Magnet Synchronous Superimposition (SI) electric motor and an Active Front-End Cycle Converter. Therefore – E means 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 require a variable-speed drive. Often medium-voltage motors fed by frequency converters and parallel shaft gears are selected. Others are using epicyclic gears with a hydrodynamic superimposition drive.
It started with hydraulic fluid couplings producing 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, and so did efficiency. The issue 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 founded on a Long lasting Magnet Synchronous Superimposition (SI) electric motor and a dynamic 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.
All of the above plots were taken by analyzing the current to the electric motor. In a normal scenario, the vibration will be monitored and stored on a periodic basis. If the 360 Hz signal exists in the vibration spectrum, it isn’t normally of any concern. If, however, other unexplained frequencies appear in the vibration spectra, then it might be advisable to have a look at both current waveform and the existing spectrum. In the web pages that follow, a few examples of problems uncovered in DC drives and motors are provided.”
It started with hydraulic fluid couplings creating slippage with results very little much better than the throttle.
The look 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, and so did efficiency. The problem of THD (Total Harmonic grid Distortion) rose and held VFD out of several applications.