Baldor 23H Series Installation & Operating Manual page 66

Section 1
General Information
Block Title Parameter
OUTPUT LIMITS Operating Zone
MIN Output Speed
MAX Output Speed Sets the maximum motor speed in RPM.
PK Current Limit
PWM Frequency
Current Rate Limit
500
400
300
200
100
HZ
50
1.00KHz
MN723
Table 4-3 Level 2 Parameter Block Definitions
Description
Sets the PWM operating zone to Standard 2.5KHz or Quiet 8.0KHz output carrier
frequency. Two output power modes are also selectable: Constant Torque and
Variable Torque.
Constant Torque allows 170 - 200% for 3 seconds overload or 150% for 60 seconds
overload.
Variable Torque allows 115% peak overload for 60 seconds.
Sets the minimum motor speed in RPM. During operation, the motor speed will not be
allowed to go below this value except for motor starts from 0 RPM or during dynamic
braking to a stop or in Process mode.
The maximum output peak current to the motor. Values above 100% of the rated current
are available depending upon the operating zone selected.
The frequency that the output transistors are switched. PWM frequency is also referred
to as "Carrier" frequency. PWM should be as low as possible to minimize stress on
the output transistors and motor windings. It is recommended that the PWM
frequency be set to approximately 16 times the maximum output frequency of the
control. Ratios less than 16 will result in non-Sinusoidal current waveforms. See
Figure 4-3.
Limits the rate of torque change in response to a torque command.
Figure 4-3 Maximum Output Frequency vs PWM Frequency
It is recommended that the PWM frequency parameter be set
to approximately16 times the maximum output frequency of
the control. The greater the ratio, the more sinusoidal the
output current waveform will be.
Note: The output current rating of the control must be
derated for operation between 8KHz and 16KHz PWM
frequency. Derating is 10% from 2.5kHz to 5kHz and
is linear from 10% at 8KHz to a 30% reduction of
rated output current at 16KHz PWM operation.
8.00KHz 16.00KHz
PWM FREQUENCY
Programming & Operation 4-15