Specifications

CT Corsair Final Report May 2, 2014
10
3.3. Induction Motor Rebuild: the How and Why
The Nord induction motors and gearbox accompanying the simulator are the original pieces of
hardware installed while the simulator was being developed at ETC. Both natural and unnatural
wear and tear have resulted in damages to the motor housings and several internal pieces. The
gearboxes were also in pieces, and one of three VFDs only worked in turning the induction
motor in the positive direction. As two induction motors are a part of the proposed design, some
work was required to get them operational.
Last year’s team purchased two non-braking induction motors for their proof of concept design.
Good fortune (or planning) had it that these two non-braking motors were of the same build; with
the exception of the brakes of course. The internal stators of the non-braking motors were
removed and installed in the braking motors. After several attempts to repair the dings and cracks
in the housings, the non-braking housings were then placed on the braking motors.
3.4 Electrical Design Modifications
Upper and Lower Limit switches were added to the design as a safety feature. The switches are
mounted above and below the maximum degree limits of cam rotation. Figure 7a and 7b show
two perspectives of an upper limit switch.
Figure 7a. (top view of upper limit switch) Figure 7b. (side view of upper limit switch.)
Two 1kΩ resistance potentiometers are being used instead of the joystick originally intended for
use. The joystick’s internal variable resistances of 1MΩ were too high and not enough current
was drawn through the control circuitry.
The original simulator’s induction motor encoders were replaced by 1MΩ pots. These pots were
fastened to the encoder gear as shown in Figure 8. Their signals are read and processed directly