Delta C2000 Series User Manual page 374

Reserved
Derating Protection
Settings 0: constant rated current and limit carrier wave by load current and
temperature
1: constant carrier frequency and limit load current by setting carrier wave
2: constant rated current(same as setting 0), but close current limit
Setting 0:
When the rated current is constant, carrier frequency (Fc) output by motor drive will auto
decrease according to surrounding temperature, overload output current and time. If overload
situation is not frequent and only cares the carrier frequency operated with the rated current for
a long time and carrier wave changes during short overload, it is recommended to set to 0.
Refer to the following diagram for the level of carrier frequency. Take VFD220C63A in
normal duty as example, surrounding temperature 50
open-type. When the carrier frequency is set to 15kHz, it corresponds to 72% rated output
current. When it outputs higher than the value, it will auto decrease the carrier frequency. If the
output is 83% rated current and the carrier frequency will decrease to 12kHz. In addition, it will
also decrease the carrier frequency when overload. When the carrier frequency is 15kHz and
the current is 120%*72%=86% for a minute, the carrier frequency will decrease to the factory
setting.
Setting 1:
It is used for the fixed carrier frequency and prevents the carrier wave changes and motor
noise caused by the surrounding temperature and frequent overload.
Refer to the following for the derating level of rated current. Take VFD220C63A in normal
duty as example, when the carrier frequency keeps in 15kHz and the rated current is decreased
to 72%, it will have OL protection when the current is 120%*72%=86% for a minute. Therefore, it
needs to operate by the curve to keep the carrier frequency.
Setting 2:
It sets the protection method and action to 0 and disables the current limit for the
Ratio*160% of output current in the normal duty and Ratio*180% of output current in the heavy
duty. The advantage is that it can provide higher output current when the setting is higher than
the factory setting of carrier frequency. The disadvantage is that it decreases carrier wave easily
when overload.
It should be used with Pr. 00-16 and Pr.00-17 for setting.
Ambient temperature will also affect the derating, please refer to ambient temperature derating
curve.
Chapter 12 Description of Parameter Settings
with independent installation and UL
12.1-06-20
Factory Setting: 0