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Chapter 4
4.3.3 Vector control with encoder feedback
- To use this control function, specify "05" (V2) for the V/F
characteristic curve selection (A044). (You can specify the vector
control with sensor only when the 1st motor control is selected.)
- Before using this function, be sure to make optimum constant
settings for the motor with reference to Section 4.2.95, "Motor
constant selection." Also, set the pulse count of the encoder to
be used.
- You can select the speed control or pulse train position control
mode by the pulse train mode setting (P013).
- When using this function, observe the following precautions:
1) If you use the inverter to drive a motor of which the capacity
is two classes lower than the maximum applicable capacity of
the inverter, you may not be able to obtain adequate motor
characteristics.
2) If the inverter does not accelerate the motor normally or the overload protection operates, check the phase
sequence of the encoder signal. (For forward rotation, phase B normally leads phase A by a phase angle of 90.)
You can check the direction of motor rotation with the actual-frequency monitoring function (d008). For checking
with this monitoring function, specify "00" (VC) for the V/F characteristic curve selection (A044) and make the
inverter operate the motor. (Normally, a positive frequency is monitored when a forward-operation command is
input, and vice versa.)
3) If you cannot obtain the desired characteristics from the motor driven under the vector control with sensor,
readjust the motor constants according to the symptom, as described in the table below.
Operation status
The motor generates an impact
Starting
when it starts.
Decelerating
The motor runs unsteadily.
Torque is insufficient during the
Torque-limited
torque-limited operation at low
operation
frequencies.
Low-frequency
Motor rotation is inconsistent.
operation
Note 1: Always set the carrier frequency (b083) to 2.1 kHz or more. If the carrier frequency is less than 2.1 kHz, the
inverter cannot operate the motor normally.
Note 2: When driving a motor of which the capacity is one class lower than the inverter, adjust the torque limit (b041
to b044) so that the value "", calculated by the expression below, does not exceed 200%. Otherwise, the
motor may be burnt out.
= "torque limit" x (inverter capacity)/(motor capacity)
(Example)
When the inverter capacity is 0.75 kW and the motor capacity is 0.4 kW, the torque limit value is
calculated as follows, based on the assumption that the value "" should be 200%:
Torque limit (b041 to b044) = x (motor capacity)/(inverter capacity) = 200% x (0.4 kW)/(0.75
kW) = 106%
Symptom
Reduce the motor constant J from the set value.
Reduce the speed response setting.
Reduce the motor constant J from the set value.
Reduce the overload restriction level to lower than the
torque limiter level.
Increase the motor constant J from the set value.
Explanation of Functions
Related code
A001: Frequency source setting
A044/A244: V/F characteristic curve selection, 1st/2nd
motors
F001: Output frequency setting
b040: Torque limit selection
b041 to b044: Torque limits (1) to (4)
H002/H202: Motor data selection, 1st/2nd motors
H003/H203: Motor capacity, 1st/2nd motors
H004/H204: Motor poles setting, 1st/2nd motors
H005/H205: Motor speed constant, 1st/2nd motors
H020/H220: Motor constant R1, 1st/2nd motors
H021/H221: Motor constant R2, 1st/2nd motors
H022/H222: Motor constant L, 1st/2nd motors
H023/H223: Motor constant Io, 1st/2nd motors
H024/H224: Motor constant J, 1st/2nd motors
H050/H250: PI proportional gain, 1st/2nd motors
H051/H251: PI integral gain, 1st/2nd motors
H052/H252: P proportional gain setting, 1st/2nd motors
P011: Encoder pulse-per-revolution (PPR) setting
P012: Control pulse setting
Adjustment method
4-97
Adjustment
item
H024/H034
H005
H024/H034
b021,
b041 to b044
H024/H034
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