Mounting The Motor; Connecting The Motor To The Load - Quin Q-drive Installation & User Manual

Q-Drive Installation Manual
6.2

Mounting the motor

The motor must be mounted rigidly to the structure of the machine or to a solid floor.
If it is not mounted securely, it may vibrate or oscillate when the motor is powered up
and the position or velocity control loops closed. The motor exerts as much torque on
its mountings as it does on the load. If the mountings are flexible, they may form a
resonant system, with the motor supplying plenty of power to sustain severe
oscillations.
6.3

Connecting the motor to the load

The motor shaft must be connected securely to the load. This may be by means of a
drive shaft, a toothed belt and pulleys, or by a gearbox. In all cases the coupling
between the motor and the load must be as stiff as possible, and must have minimum
backlash. At the same time, care must be taken to avoid adding any unnecessary friction
into the system, as this reduces the performance of the servo system.
A common problem when connecting the motor to its load is backlash. This is usually
found in gearboxes, where the input gear is allowed to move by a small amount between
the teeth of the output gear, while the output gear is stationary. A similar effect is seen
if the motor mountings are loose or sloppy, or if the coupling between motor and load
is too flexible. The effect of backlash is not just a loss of position accuracy, but may in
extreme cases result in a highly unstable system. All possible precautions must be taken
to minimise or eliminate backlash in the system.
Page 32 Copyright © 1996 Quin Systems Ltd.
Issue 1.5