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 using epicyclic gears with a hydrodynamic superimposition drive.

Taking advantage of the condition of the art in Variator Gearbox electric motors and frequency converters, the driving system for the superimposition of the planet carrier is founded on a Permanent Magnet Synchronous Superimposition (SI) motor and an Active Front-End Cycle Converter. So – E means Electric.
That is a high-speed gear drive system incorporating elements that allow the utilization of a low-cost constant-speed (electric) driver for a variable-speed application.

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 employing epicyclic gears with a hydrodynamic superimposition drive.
It started with hydraulic liquid 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, at the same time, the expense of the shaft trains increased, and so did efficiency. The problem of THD (Total Harmonic grid Distortion) rose and kept VFD out of many applications.

Taking advantage of the condition of the art in electrical motors and frequency converters, the driving program for the superimposition of the planet carrier is based on a Long lasting Magnet Synchronous Superimposition (SI) engine and a dynamic Front-End Cycle Converter. Therefore – E means 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 above plots were taken by analyzing the existing to the engine. In a normal circumstance, the vibration will be monitored and stored on a periodic basis. If the 360 Hz signal exists 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 have a look at both the current waveform and the existing spectrum. In the web pages that follow, some examples of problems discovered in DC drives and motors are provided.”
It started with hydraulic fluid couplings creating slippage with results very little 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, at the same time, the price of the shaft trains increased, therefore did efficiency. The issue of THD (Total Harmonic grid Distortion) rose and kept VFD out of several applications.