Lenze EVF9383 - Manual (Page 177)

Switching frequency of the inverter 6.9
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6.9−1 EDSVF9383V EN 7.1−04/2012
6.9 Switching frequency of the inverter
The switching frequency of the inverter influences the smooth running
behaviour, the power loss in the controller and the noise generation in the
connected motor. The Lenze setting is the optimal value for standard
applications. The following general rule applies:
The lower the switching frequency, the
ƒ lower the power loss.
ƒ higher the noise generation.
ƒ better the concentricity factor.
You can select between two switching frequency modes:
Code sine−wave modulated (sin) flat−top modulated (f_top)
C0018 1, 2, 4, 6 3
)
Note!
ƒ The concentricity factor at low speeds is lower with flat top
modulation than with sine−wave modulation. For standard
application a sine−wave modulated switching frequency is
optimal.
ƒ The maximum output frequency of the controller depends on
the selected switching frequency (see C0018).
ƒ With C0018 = 6, the switching frequency will be automatically
changed depending on the output current of the controller.
ƒ Please observe that the output current must be reduced when
operating with high switching frequencies to prevent an
impermissible heating of the controller (derating).
ƒ Adapt the current limit values (C0022 and C0023) so that the
currents specified in the technical data are not exceeded.
Moreover, you can adjust whether it is switched to a lower switching
frequency when the heatsink temperature reaches an adjustable limit value.
This prevents the drive from being inhibited by the error "overtemperature"
and the motor coasts without torque.
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