Parker 890CD - Page 422

Programming
Page D-78 890CS Common Bus Supply - Frames B & D; 890CD Common Bus Drive and 890SD Standalone Drive - Frames B, C & D
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Functional Description
The Drive provides a unique quiet pattern PWM strategy in order to reduce audible motor noise. The user is able to select
between the quite pattern or the more conventional fixed carrier frequency method. With the quiet pattern strategy selected
(random pattern enabled), audible motor noise is reduced to a dull hiss.
In addition, the user is able to select the PWM carrier frequency. This is the main switching frequency of the power output
stage of the Drive. A high setting of carrier frequency (e.g. 6kHz) reduces audible motor noise but only at the expense of
higher Drive losses and smooth motor rotation at low output frequencies. A low setting of carrier frequency (e.g. 3kHz),
reduces Drive losses but increases audible motor noise.