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 using epicyclic gears with a hydroVariator Gearbox dynamic 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 founded on a Long lasting Magnet Synchronous Superimposition (SI) engine and an Active Front-End Cycle Converter. So – 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.
A lot more than 50% of the compression and pumping systems above 3 MW require 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 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, simultaneously, the expense of the shaft trains improved, and so did efficiency. The problem of THD (Total Harmonic grid Distortion) rose and kept VFD out of many applications.
Taking benefit of the state of the artwork in electric powered motors and frequency converters, the driving system for the superimposition of the earth carrier is founded on a Permanent 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 components that allow the usage of a low-cost constant-speed (electric) driver for a variable-speed application.
All of the above plots were taken by analyzing the existing to the engine. In a normal circumstance, 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, other unexplained 
frequencies come in the vibration spectra, then it might be advisable to take a look at both the current waveform and the current spectrum. In the webpages that follow, a few examples of problems discovered in DC drives and motors are presented.”
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.
Variable Frequency Drives (VFD) were developed and, at the same time, the cost of the shaft trains improved, therefore did efficiency. The problem of THD (Total Harmonic grid Distortion) rose and kept VFD out of several applications.