Omron RX Series User Manual page 361

Constant Torque Characteristics (VC)
This setting is suitable for cart, conveyor, overhead traveling crane, and other applications where a
constant torque is required, independent of the motor rotation speed.
The output voltage is generated in proportion to the output frequency to realize the output of a constant
torque.
However, the output voltage is proportional from 0 Hz to the base frequency, it is constant independent
of the frequency, from the base frequency to the maximum frequency.
For the base frequency, set the rated frequency of the motor. For the maximum frequency, set the
highest frequency required for your application, within the maximum frequency of the motor.
Reduced Torque Characteristics (VP 1.7th Power (VC at Low Speed))
This setting is suitable for fan, pump, and other applications that do not require large torque at low
speeds.
It provides high efficiency, reduced noise, and vibration, because the output voltage is reduced in the
low speed range.
In only the low speed range at 10% of the base frequency or less, the setting provides constant torque
characteristics (VC) to secure a sufficient starting torque.
Range (a):
Constant torque characteristics are provided from 0 Hz to 10% of the base frequency.
(Example) If the base frequency is 60 Hz, the setting provides constant torque characteristics from 0 to
6 Hz.
Range (b):
Reduced torque characteristics are provided from 10% to 100% of the base frequency.
The inverter outputs voltage based on a curve of the 1.7th power of the frequency.
Range (c):
Constant voltage characteristics are provided from the base frequency to the maximum frequency.
High-function General-purpose Inverter 3G3RX-V1 User's Manual (I578-E1)
Output
voltage [%]
0
Base frequency
Output
voltage [%]
1.7
VP(f )
VC
0
10% of base
Base
frequency
frequency
(a) (b) (c)
Output frequency [Hz]
Max. frequency
Output frequency [Hz]
Max.
frequency
7 Detailed Functions
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