LEESON Micro Series Compact Inverters - Manual (Page 62)

22 TORQUE (TORQUE CURVE SELECTION)
This parameter is used to select whether the output of the drive follows a constant or variable V/Hz curve.
The following selections are available:
CONSTANT Use for constant torque applications to optimize torque.
VARIABLE Use for variable torque applications to optimize energy savings.
CT/NOCMP Use for constant torque applications that require full overload capacity at low speeds
(see Parameter 17 - MOTOR OL).
23 CARRIER (CARRIER FREQUENCY)
This parameter sets the carrier frequency, or switching frequency of the output IGBT’s. Higher switching
rates result in less audible noise to be emitted from the motor, but the efficiency of the drive decreases as
the carrier frequency increases. Therefore, this parameter should be set to the lowest value which yields
acceptable sound levels. Available settings are: 2.5 kHz, 6.0 kHz, 8 kHz, 10 kHz, 12 kHz and 14 kHz.
NOTE 1: The 2.5 kHz carrier frequency setting is a variable carrier. The carrier frequency remains fixed at
1.5 kHz up to 25 Hz output frequency. Above 25 Hz, the carrier is a fixed multiple of 60 times the drive’s
output frequency. For example, if the output frequency of the drive was set to 45 Hz, the carrier frequency
would be 2.7 kHz (45 Hz x 60 = 2700 Hz).
NOTE 2: The ability to operate a drive in the quiet (high carrier frequency) mode is dependent on the
drive horsepower rating, driven load, drive enclosure, and the ambient temperature . At full ambient tem-
perature, operation above 8 kHz requires derating the drive by multiplying the output current rating by the
following factors: 0.94 at 10 kHz, 0.89 at 12 kHz, and 0.83 at 14 kHz.
NOTE 3: If the drive is equipped with the High Output Frequency option, and MAX FRQ is set above 120
Hz, CARRIER will automatically change to 14 kHz, and the CARRIER parameter will disappear from the
parameter menu . Operation at 14 kHz carrier frequency requires derating as shown in NOTE 2 above.
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