A lot more than 50% of the compression and pumping systems above 3 MW need a variable-speed drive. Frequently medium-voltage motors fed by frequency converters and parallel shaft gears are chosen. Others are employing epicyclic gears with a hydrodynamic superimposition drive.
Taking benefit of the state of the artwork in electric powered motors and frequency converters, the driving system for the superimposition of the planet carrier is based 
on a Permanent Magnet Synchronous Superimposition (SI) Variable Speed Gearbox 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.
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 chosen. Others are employing epicyclic gears with a hydrodynamic superimposition drive.
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, at the same time, the expense of the shaft trains increased, and so did efficiency. The issue of THD (Total Harmonic grid Distortion) rose and held VFD out of several applications.
Taking advantage of the state of the artwork in electric motors and frequency converters, the driving system 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 stands for Electric.
That is a high-speed gear drive system incorporating parts 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 engine. In a normal situation, the vibration will be monitored and kept on a periodic basis. If the 360 Hz signal exists in the vibration spectrum, it isn’t normally of any concern. If, however, various other unexplained frequencies come in the vibration spectra, after that it would be advisable to have a look at both current waveform and the current spectrum. In the webpages that follow, some examples of problems discovered in DC drives and motors are offered.”
It started with hydraulic liquid couplings generating slippage with results very little 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 expense of the shaft trains improved, therefore did efficiency. The issue of THD (Total Harmonic grid Distortion) rose and kept VFD out of several applications.