Lenze MC1000 Series User Manual

Page 57

13435742_EDBM101_v24

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).

CARRIER

(CARRIER FREQUENCY)

This parameter sets the carrier, or switching, frequency of the output IGBT’s. Higher

switching rates result in less audible noise 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 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 temperature, 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.