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Adjustment of the output torque (current) of the motor
(4) Setting of stall prevention operation in high frequency range (Pr. 22, Pr. 23, Pr. 66)
Pr. 22
When Pr. 23 = 9999
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
Stall prevention operation level
in high frequency range (%)
However,
A =
By setting "9999" (initial value) in Pr. 23
prevention operation level is constant at the Pr. 22 setting up to 400Hz.
(5) Set two types of stall prevention operation levels (Pr. 48)
Turning RT signal ON makes Pr. 48
For the terminal used for RT signal input, set "3" in any of Pr. 178 to Pr. 182 (input terminal function selection) to assign the
function.
NOTE
Changing the terminal assignment using Pr. 178 to Pr. 182 (input terminal function selection) may affect the other
functions. Set parameters after confirming the function of each terminal.
The RT signal acts as the second function selection signal and makes the other second functions valid.
(Refer to page 119.)
(6) To further prevent a trip (Pr. 154)
Set Pr.154 Voltage reduction selection during stall prevention operation = "11" when the overvoltage protective function (E.OV
activates during stall prevention operation in an application with large load inertia. Note that turning OFF the start signal
(STF/STR) or varying the frequency signal during stall prevention operation may delay the acceleration/deceleration start.
84
When Pr. 23 = "9999", the stall prevention
operation level is as set in Pr. 22 to 400Hz.
Stall prevention operation level
as set in Pr. 23
400Hz
Output frequency (Hz)
= A + B
Pr. 22
(Hz)
(%)
Pr. 66
, B =
Output frequency (Hz)
Stall prevention operation level compensation factor at double speed
Second stall prevention operation current
Setting example
150
90
60
45
30
22.5
0
Pr. 22 -
A
Pr. 23
[
] [
- B
100
Pr. 22
Pr. 22
(
)
Pr. 66
Hz
400Hz
valid.
(Pr. 22 = 150%, Pr. 23 = 100%, Pr. 66 = 60Hz)
60
100
150
200
300
Output frequency (Hz)
- 100
]
(
)
%
400
, the stall
)
[]
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