Lenze MCH Series - Manual (Page 58)

54 13435744_EDBMH01_v13
OUTPUT FREQUENCY (Hz)
OUTPUT VOL
TA
GE
(%)
FIXED BOOST
CONSTANT V/Hz
10 20 30 40 50 60
10
20
30
40
50
60
70
80
90
100
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.
CONST / NO COMP Use for constant torque applications that require full overload
capacity at low speeds (Refer to Parameter 17 - MOTOR OL).
23 CARRIER FREQ
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 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). The other
settings are constant carriers that remain fixed for the entire speed range.
NOTE 2: The ability to operate a drive at higher carrier frequencies is dependent
on the drive horsepower rating, driven load, drive enclosure and the
ambient temperature. Operation above 8kHz 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.