More than 50% of the compression and pumping systems over 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.
Taking benefit of the state of the art in electric powered motors and frequency converters, the driving program for the superimposition of the planet carrier is founded on a Long term Magnet Synchronous Superimposition (SI) engine and an Active Front-End Cycle Converter. So – E stands for Electric.
That is a high-speed gear drive system incorporating parts that allow the usage 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 selected. Others are employing epicyclic gears with a hydrodynamic superimposition drive.
It started with hydraulic fluid 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 cost of the shaft trains improved, therefore did efficiency. The issue of THD (Total Harmonic grid Distortion) rose and kept VFD out of many applications.
Taking benefit of the state of the art in electric powered motors and frequency converters, the driving program for the superimposition of the earth carrier is based on a Permanent Magnet Synchronous Superimposition (SI) motor and an Active Front-End Cycle Converter. So – E means Electric.
This is a high-speed gear drive system incorporating components that allow the utilization 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 engine. In a normal scenario, the vibration will become monitored and kept on a Variator Gearbox periodic basis. If the 360 Hz signal is present in the vibration spectrum, it is not normally of any concern. If, however, various other unexplained frequencies come in the vibration spectra, then it might be advisable to check out both the current waveform and the existing spectrum. In the web pages that follow, a few examples of problems found out in DC drives and motors are offered.”
It started with hydraulic fluid couplings creating 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.
Variable Frequency Drives (VFD) were developed and, at the same time, the cost of the shaft trains increased, therefore did efficiency. The issue of THD (Total Harmonic grid Distortion) rose and held VFD out of many applications.