YASKAWA CIMR-F7A Instruction Manual page 200

Difference Between CT and VT
The characteristics of CT (low carrier, constant torque) and VT (high carrier, variable torque) are shown
below.
CT: Low Carrier, Constant Torque
Constant Torque
Torque
Motor speed
0
Constant torque means a constant load torque for all
motor speed, and it requires overload resistance capabil-
ity. Applications include pushers, conveyors, cranes, and
other friction or heavy loads.
Low carrier: Electromagnetic noise is present.
Setting Precautions
C6-01 (CT/VT Selection)
When setting C6-01, observe the following precautions.
Depending on the set value in C6-01, the setting range of the related constants is limited as follows:
•
C6-01 Set Value
Inverter Overload Protection Level
C6-02 (Carrier Frequency Selection)
E1-04 and E3-02 (Max. Output Fre-
quency)
L3-02 (Stall Prevention Level During
Acceleration)
L3-06 (Stall Prevention Level During
Operation)
* Factory settings depend on Inverter capacity.
200 V and 400 V Class Inverters for 0.4 to 22 kW: 6 (15 kHz)
200 V Class Inverters for 30 kW, or 400 V Class Inverters for 30 to 55 kW: 4 (10 kHz)
200 V Class Inverters for 37 to 55 kW, or 400 V Class Inverters for 75 to 110 kW: 3 (8 kHz)
200 V Class Inverters for 75 to 90 kW, or 400 V Class Inverters for 132 to 185 kW: 2 (5 kHz)
200 V Class Inverter for 110 kW, or 400 V Class Inverters for 220 to 300 kW: 1 (2 kHz)
When the setting in E1-04 or E3-02 is greater than 150 Hz (SPEC: C or earlier),
•
or later) , if C6-01 is set to 0, an OPE02 (Invalid constant setting range) error will occur.
VT: High Carrier, Variable Torque
Torque
Variable torque means that the load torque will decrease
as the speed decreases. Normally, overload resistance
capability is not required. Applications include fans and
pumps.
High carrier: Electromagnetic noise is not present.
0 (Low Carrier, Constant
Torque)
150% Inverter rated current/1
min.
0: Low carrier, low noise
1: Carrier 2.0 kHz
300 Hz
150Hz,
150%
150%
Application and Overload Selections
Variable Torque
Motor speed
1 (High Carrier, Variable
Torque)
120% Inverter rated current/1
min.
0: Low carrier low noise
1: Carrier 2.0 kHz
2: Carrier 5.0 kHz
3: Carrier 8.0 kHz
4: Carrier 10.0 kHz
5: Carrier 12.5 kHz
6: Carrier 15.0 kHz
F: User-set*
400 Hz
120%
120%
300 Hz (SPEC: E
3
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