Parameter Reference C-123
AC30 series Variable Speed Drive
This parameter selects between random pattern (quiet motor noise) or the more conventional fixed carrier PWM strategies, for
induction motor only. When TRUE, random pattern is enabled. For Induction Motor Control, random pattern is only suitable for Stack
Frequency <=12kHz.Default value for induction motors is TRUE.
If the Peer To Peer feature is enabled, random pattern is only suitable for Stack Frequency <= 6 kHz
Random Pattern PMAC
1268
Parameters::Motor Control::Pattern
Generator
FALSE
ALWAYS
This parameter selects between random pattern (quiet motor noise) or the more conventional fixed carrier PWM strategies, for PMAC
motor only. When TRUE, random pattern is enabled. For PMAC SVC control random pattern is only suitable for Stack Frequency
<=8kHz. Default value for PMAC motors is FALSE.
If the Peer To Peer feature is enabled, random pattern is only suitable for Stack Frequency <= 6 kHz
Deflux Delay
0414
Parameters::Motor Control::Pattern
Generator
1.000
0.000 to 60.000
s
STOPPED
Sets the minimum allowed delay between disabling and then re-enabling PWM production (i.e. stopping and starting the drive).
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 quiet 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.