Innovative variable-speed turnkey test rig with a wide performance envelope and integrated data acquisition & control system.
The University of Nottingham had a requirement for the design and manufacture of a test-bed with 4-quadrant loading capability for research and development testing of high speed aerospace starter-generators. The test system was rated to a minimum of 150kW at 35,000rpm and had to deliver performance over several operating points to provide optimum flexibility.
Torquemeters designed, manufactured, installed and commissioned a 150kW full 4-quadrant test-rig for accurately testing a variety of different starter / generator test-articles for research in the aerospace industry. The key system elements comprised a Variable Frequency Drive (VFD), an AC induction motor to act as both a driver and absorber, a multiple-output parallel-shaft gearbox, lubrication system, an in-line phase-shift ET1303 Torquemeter, high-speed low-mass couplings and a rig health monitoring system which included control of the motor. All components, bar the VFD and lubrication system, were mounted on a base frame designed by Torquemeters.
One of the key components of the installed test-rig was the Torquemeters-designed multiple output gearbox. The gearbox has three output shafts; two speed-increasing outputs and a third straight-through output (to match the speed of the AC Dyno). The multiple outputs deliver three performance envelopes giving maximum flexibility for testing and characterising of the test-article. All outputs are rated at 150kW with maximum output speeds of 5,700, 17,700 and 35,000rpm.
As a high-level of accuracy was required our own ET1303 Torquemeter (max. speed 36,000rpm / max. torque 300Nm) was selected. This model has an absolute measurement accuracy of 0.1% full-scale, as do all ET Torquemeters.
On the two high-speed gearbox outputs Torquemeters own Tordisc diaphragm couplings were used. These are extremely lightweight, low-overhung mass couplings to maximise the bearing life of the machines that they are installed between.
The test-bed mounting frame had a high-precision mounting system to allow for both repeatable and accurate mounting of various test-articles and a traverse system to switch quickly and accurately between the three gearbox outputs.
Key features of the installations include;