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PARAMETERS
5
Adjustment of the output torque (current) of the motor
(5) Setting of stall prevention operation in high frequency range (Pr. 22, Pr. 23, Pr. 66)
During high-speed operation above the rated motor frequency, acceleration may not be made because the motor current
does not increase. If operation is performed in a high frequency range, the current at motor lockup becomes smaller than
the rated output current of the inverter, and the protective function (OL) is not executed even if the motor is at a stop.
To improve the operating characteristics of the motor in this case, the stall prevention level can be reduced in the high
frequency range. This function is effective for performing operation up to the high-speed range on a centrifugal separator
etc. Normally, set 60Hz in Pr. 66 and 100% in Pr. 23.
Formula for stall prevention operation level
By setting "9999" (initial value) in Pr. 23
Stall prevention operation level compensation factor at double speed, the stall
prevention operation level is constant at the Pr. 22
setting up to 400Hz.
(6) Set two types stall prevention operation levels (Pr. 48)
Turning RT signal ON makes Pr. 48 Second stall prevention operation current valid.
Stall prevention operation level
in high frequency range (%)
=A + B × [
Pr. 22 - A
] × [
Pr. 23 - 100
]
Pr. 22 - B
100
However, A =
Pr. 66 (Hz) × Pr. 22 (%)
,B=
Pr. 66 (Hz) × Pr. 22 (%)
Output frequency (Hz)
400Hz
NOTE
The RT signal acts as the second function selection signal and makes the other second functions valid.
(Refer to page 143)
Output frequency (Hz)
Pr. 22
When Pr. 23 = 9999
Pr. 66
400Hz
Stall prevention operation
level (%)
Stall prevention operation level
as set in Pr. 23
When Pr. 23 = "9999", the stall prevention
operation level is as set in Pr. 22 to 400Hz.
Output frequency (Hz)
Setting example
30
22.5
0 10060 200150 300 400
45
60
90
150
Stall prevention
operation level
(%)
(Pr. 22 = 150%, Pr. 23 = 100%, Pr. 66 = 60Hz)