80
"A" Group: Standard Functions Section 3-5
quency setting (A004/A204) automatically. (The inverter regard the value of
free-setting V/F frequency 7 (
b112) as the maximum frequency.)
Manual Torque Boost -
The Constant and Variable
Torque algorithms feature
an adjustable torque boost
curve. When the motor
load has a lot of inertia or
starting friction, you may
need to increase the low
frequency starting torque
characteristics by boost-
ing the voltage above the
normal V/f ratio (shown at right). The function attempts to compensate for volt-
age drop in the motor primary winding in the low speed range.
The boost is applied from zero to the base frequency. You set the breakpoint
of the boost (point A on the graph) by using parameters
A042 and A043. The
manual boost is calculated as an addition to the standard V/f curve.
Be aware that running the motor at a low speed for a long time can cause
motor overheating. This is particularly true when manual torque boost is ON,
or if the motor relies on a built-in fan for cooling.
Output voltage (V)
V7 ( b113)
V6 ( b111)
V5 ( b109)
V4 ( b107)
V1 ( b101)
V2,3 ( b103,b105)
0
F1
(b100)
F2
(b102)
F3
(b104)
F4
(b106)
F5
(b108)
F6
(b110)
F7
(b112)
Output freq.(Hz)
Item Code Set range Remarks
Free-setting V/F freq. (7) B112 0 to 400 (Hz)
*1
Setting of the out-
put freq. at each
breakpoint of the
V/F characteristic
curve
Free-setting V/F freq. (6) B110 Free-setting V/F freq.5 to freq.7 (Hz)
Free-setting V/F freq. (5) B108 Free-setting V/F freq.4 to freq.6 (Hz)
Free-setting V/F freq. (4) B106 Free-setting V/F freq.3 to freq.5 (Hz)
Free-setting V/F freq. (3) B104 Free-setting V/F freq.2 to freq.4 (Hz)
Free-setting V/F freq. (2) B102 Free-setting V/F freq.1 to freq.3 (Hz)
Free-setting V/F freq. (1) B100 0 to Free-setting V/F freq.2 (Hz)
Free-setting V/F volt. (7) B113 0.0 to 800.0 (V) Setting of the out-
put voltage at each
breakpoint of the
V/F characteristic
curve
*2
Free-setting V/F volt. (6) B111
Free-setting V/F volt. (5) B109
Free-setting V/F volt. (4) B107
Free-setting V/F volt. (3) B105
Free-setting V/F volt. (2) B103
Free-setting V/F volt. (1) B101
*1
Up to 1000Hz for High frequency mode (d060 set to "2")
*2
Even if the voltage higher than input is set as a free-setting V/F voltage 1 to 7, the inverter output voltage cannot exceed
the inverter input voltage or that specified by the AVR voltage selection. Carefully note that selecting an inappropriate
control system (V/F characteristics) may result in overcurrent during motor acceleration or deceleration or vibration of the
motor or other machine driven by the inverter.
0
A042
= 5 (%)
30 Hz
V
100%
1.8 Hz
A043
= 3 (%)
Hz
A
5% voltage
boost
(100%=A082)
fbase =
60 Hz
To Next Page
Loading...
