Chapter 5 Detailed Function Introductions
148
Notes:
The motor
’
s slip changes with the load torque, which results in the variance of motor speed. The inverter
output frequency can be adjusted automatically through slip compensation according to the load torque.
Therefore, the electrical characteristics of the mechanical hardness are improved. As shown in Figure. 5-9-4.
Synchronous
speed
n
T
Freq. after
compensation
Compensation Freq.
f
Load torque
Figure. 5-9-4 Auto slip compensation diagram
In the case of rating torque, the slip compensation value is equal to compensation gain (P9.09)
×
rating slip
(synchronous rotating speed – rating rotating speed);
Motor-driving state: when the actual rotating speed is lower than the given speed, the compensation gain
(P9.09) should be increased gradually;
Power-generation state: when the actual rotating speed is higher than the given speed, the compensation
gain (P9.09) should be increased gradually.
Tips:
The automatic slip compensation is related to the rating slip of motor. When the slip compensation function is used,
the rating rotating speed of motor should be set correctly (PA.03 and PA.17).
When the compensation gain is 0, the slip compensation will be ineffective.
P9.11 Energy saving control selection
Setting range: 0.1 [0]
0: Effective Energy Conservation
1: Ineffective Energy Conservation
Notes:
The energy saving control parameters have been preset at the factory to the optimum values. It is not necessary
to adjust them under normal operation. If your motor characteristic has great difference from those of
standard induction motors, refer to the following description to adjust the parameters.
P9.12 Energy saving gain coefficient
Setting range: 0.00~655.3 [This value depends on the inverter
model
]
Notes:
In the energy conservation control mode, the energy conservation gain factor is used to calculate the voltage of
motor at its highest efficiency, which is used as the output voltage. The energy conservation factor P9.12 is
preset according to the value of standard motor before it leaves the factory. When the energy conservation
gain factor increases, the output voltage will increase as well.
P9.13 Energy saving voltage lower
limit(50Hz)
Setting range: 0
~
120% [50%
]
P9.14 Energy saving voltage lower
limit(5Hz)
Setting range: 0
~
25% [12%
]
Notes:
These parameters are used to set the lower limit of output voltage. If the voltage reference value calculated in
the energy saving mode is smaller than the energy saving voltage lower limit, the energy saving voltage
limit will be treated as the output voltage reference. To prevent the motor stalling at light loads, the energy
saving voltage lower limit must be set. Set voltage limits at 5Hz and 50Hz; the setting value is obtained by
