• Spin-testing of rotating components to bursting point
• Burst-proof enclosure, high safety standard
• DC drive with regenerative braking
• Testing above or below ambient temperature
• Compact design, easy assembly

Design

The test system comprises a vacuum chamber designed to absorb the maximum expected energy of the specimen fragments on bursting of the rotor. The vacuum chamber is installed on a foundation to be prepared by the customer. For ease of handling, the chamber is always installed at least partly above floor level.
The chamber is equipped with a lid, which carries the mechanical and electrical drive components. The mechanical drive components consist of either a planetary gearbox or a precision spindle mounted on antifriction bearings. For testing a large spectrum of different rotors, several different mechanical drive systems can be used, catering for a wide range of rotor weights and speeds. Quick-disconnect couplings are used to enable fast and easy replacement  of the different drive components. The electrical drive system is a thyristor controlled, DC-shunt motor or a three-phase servo motor with frequency converter.
The lid is locked to the vacuum chamber with an automatically engaged locking device, rated for extremely high internal pressures. Opening of the lid due to axially acting energy of specimen fragments or dust explosion is thus prevented.
The CAST NT computer system is designed for test rig control, data acquisition and evaluation. The system comprises a computer with monitor and printer and the software modules CASTControl and CASTView. CASTControl supports 16 analog measured variables such as speed, shaft vibration, vacuum, temperature etc. CASTView provides a convenient interface for visualization of measured values in online and offline mode.

Range of appliation

Vertical spin test systems enable rotating components to be analyzed under the influence of centrifugal forces. These systems are indispensable in research and development, production and quality assurance for components such as jet engines, gas turbines, turbo compressors, turbo chargers, fans, commutators, clutches, wood-working tools and HSG components.
Their main areas of application are:
Pre-stressing of materials by accelerating rotating components beyond the yield point.
Testing of material strength at speeds above operational speed within the framework of quality assurance. Acceleration of rotating components to bursting point for research and development.
Low-cycle fatigue tests to establish Woehler diagrams, automatic execution of all testing cycles.

Principle of operation

To prepare the test, the component is mounted on a spin testing arbor. This arbor is a critical component and has to be designed in such a way that the fit between the bore and the arbor is optimally adapted to requirements. Balancing of the unit rotor/arbor assembly is not absolutely necesary but recommended to improve smooth running. The drive system developed by Schenck, featuring flexible rotor attachment and a highly efficient hydro-mechanical damping system, allows even rotors with minor unbalance to be tested.  Rotor and arbort ogether are vertically connected to the drive shaft. The drive shaft itself is connected with its upper end to the output shaft of the mechanical drive system and penetrates this completely freely. This principle provides for flexible suspension, a feature which is particularly important, as it  guarantees that testing always takes place above the first natural frequency of the drive shaft/arbor/rotor vibratory system. Vibration problems within the range of test speeds are thus avoided.