Mitsubishi FR-A740-00023-EC, Инструкция по эксплуатации

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145
Adjust the output torque of the motor (current)
4
P
ARAME
T
E
R
S
(2) Stall prevention operation signal output and output timing adjustment (OL signal, Pr. 157 )
⋅
When the output power exceeds the stall prevention operation level and stall prevention is activated, the stall
prevention operation signal (OL signal) turns on for longer than 100ms. When the output power falls to or below the
stall prevention operation level, the output signal turns off.
⋅
Use
Pr. 157 OL signal output timer
to set whether the OL signal is output immediately or after a preset period of time.
⋅
This operation is also performed when the regeneration avoidance function (overvoltage stall) is executed.
(3) 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 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 50Hz in
Pr. 66 and 100% in Pr. 23 .
⋅
Formula for stall prevention operation level
⋅
When
Pr. 23 Stall prevention operation level compensation factor at double speed
= "9999" (initial value), the stall
prevention operation level is kept constant at the Pr. 22 setting up to 400Hz.
Pr. 157 Setting Description
0
(initial value)
Output immediately
0.1 to 25 Output after the set time (s) has elapsed
9999 Not output
REMARKS
⋅
The OL signal is assigned to the terminal OL in the initial setting. The OL signal can also be assigned to the other terminal by
setting "3 (positive logic) or 103 (negative logic)" to any of
Pr. 190 to Pr. 196 (output terminal function selection) .
CAUTION
· If the frequency has fallen to 0.5Hz by stall prevention operation and remains for 3s, an alarm (E.OLT) appears to shutoff the
inverter output.
· When terminal assignment is changed using Pr. 190 to Pr. 196 (output terminal function selection) , the other functions may be
affected. Please make setting after confirming the function of each terminal.
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 (H) 400Hz
Overload state
(OL operation)
OL output signal
Pr.157
Set time(s)
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
Stall prevention operation level (%)
Pr. 22
=
150%
Pr. 23 = 100%
Pr. 66 = 50Hz
150
75
37.5
25
18.75
50 0 100 200 300 400