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On the tradeoffs between power density, efficiency and cost for high-performance, electric motors in choosing the most applicable technology for a specific application.
The main function of rolling bearings is to support load and transmit rotational movement with minimum energy loss. In order to achieve this, bearings are manufactured with particularly good quality fatigue resistance materials, proper design and tight manufacturing tolerances. Particular emphasis is put in both the macro, and micro geometry of the working shapes and surfaces of the raceways. Rolling bearings come in many types and sizes as ball and roller bearings for radial and thrust loads.
If torque conversion with high gear ratio, compact installation space and 90-degree axis-crossing angle is needed, often worm gears are used. Due to their high power density and sliding speeds within the tooth contact, frictional heat and thermal stresses are higher compared to helical, bevel and hypoid gears, and thus the thermal load capacity of worm gears is lower.
Motion control systems often combine high power drive signals in close proximity (or even within the same cable) with lower level signals, like encoders. You will often see ferrite beads added around cables; their effectiveness in minimizing noise is greatly affected by how they are deployed. This involves which signals are grouped, what are the drive characteristics, and how shielding and grounding are handled in the system.
Three-dimensional finite element analysis (FEA) simulation and research from published information is used to compare the features of various coil configurations.
These versatile, low-cost and high-torque motors may be used open loop or as full servos - and several levels in between. The motor stator laminate designs divide these motors into those optimized for full stepping, and those optimized for micro stepping and servo operation. These differences can be easily measured with basic meters and oscilloscopes. Motor to motor variations can also be easily measured, and motor inductance at nominal speed and current can also be determined.
Rolls-Royce is pioneering the UltraFan engine family architecture containing a planetary gearbox in a power range of 15 to 80 megawatts. To increase the efficiency of the UltraFan, a planetary gearbox is introduced between fan and intermediate pressure compressor. This enables running the turbine to rotate faster and allows a reduced fan speed.