Germany-based specialist in drive technology Renk is presenting a new mechanical variable-speed drive with a superimposition low-voltage induction electric motor to control the speed of compressors or pumps.
Recovar-E is a mechanical variable-speed drive with a superimposition low-voltage induction electric motor to control the speed of compressors or pumps. The name stands for Renk ECOnomic VARiator, the E indicating the electric superimposition drive.
For most compressors and pumps above 3 MW using variable-frequency drives (VFD) with medium-voltage electric motors, Recovar-E becomes an alternative solution bringing benefits in efficiency, maintenance and total harmonic grid distortion (THD).
Energy efficiency is the main advantage of this system; for lower speeds, the superimposition recycles the power subtracted from the main driver. For higher speeds, with the power of superimposition added to the main motor, the main motor can be downsized with lower purchase costs and lower losses.
System losses with the Recovar-E are lower than those in systems with hydrodynamic superimposition. According to Renk, Recovar-E has an efficiency performance of 95% across the whole speed range (Recovar-E covers speeds between 70% and 105%, but a larger speed range can be achieved).
Another advantage of the Recovar-E is its easy maintenance, a feature that also helps during first assembly.
The configuration of the power-splitting gear set is composed of three planets and features a full horizontal split line that allows the user to remove each planet with its bearings and the central pinions directly on site, without the need for removing the gear from the foundation. The superimposition motor can be removed on site too without disrupting the casing alignment.
Renk will demonstrate the Recovar-E variable-speed drive with electric superimposition during an event at its Augsburg, Germany headquarters on Feb. 12, 2020. More information can be found at: www.renk.biz.