The Bently Nevada RK4 rotor kit is a miniature, bench top rotating machine that simulates a number of machinery malfunctions including unbalance, rubs, fluid-induced instabilities, loose rotating parts, preloads, and others. Its unique geometry and its ability for users to isolate and control individual machine characteristics make it useful as both a teaching tool and as a laboratory tool for theoretical research.

In addition to machinery behavior, the rotor kit can be used to teach the fundamentals of proximity probe placement, gapping, and troubleshooting. It can also help technicians learn how to read and interpret proximity probe signals using an oscilloscope.

The Bently Nevada RK4 rotor kit has a V-frame design that has been developed to provide better control of the housing dynamic stiffness properties. The mechanical tolerances have also been tightened, resulting in more accurate machine behavior modeling. The RK4 rotor kit motor can closely hold the desired speed with changes in loading conditions. This has been accomplished by incorporating a direct current motor and high performance control circuitry. The motor can run in either a clockwise or counter-clockwise direction and has adjustable slow roll speed capability. It can be controlled remotely by using a ±5 volt control input, such as a signal generator or dc power supply, to drive the motor speed control device. Rotor speed is displayed on a digital tachometer with a large LCD readout.