(A041/A241), base frequency setting (A003/A203), and maximum frequency setting (A004/A204) automatically. (The inverter regard the value of free-setting V/F frequency 7 (b112) as the maximum frequency.)
Item Code Set range Remarks
Free-setting V/F freq. (7) B112 0 to 400 (Hz)
Setting of the output 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 output voltage at each breakpoint of the V/F characteristic curve *1) 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) 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.
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)
3−24
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 boosting the voltage above the normal V/f ratio (shown at right). The function attempts to compensate for voltage 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.
Voltage gain – Using parameter A045 you can
modify the voltage gain of the inverter (see graph at right). This is specified as a percentage of the full scale output voltage. The gain can be set from 20% to 100%. It should be adjusted in accordance with the motor specifications. Gain can be changed even during operation in V/f mode, and while stopped in SLV mode. When the setting is changed , reset (RS terminal on/off) is to be executed so that the motor constants are re-calculated.
After the setting is done, please be sure to reset (terminal RS on/off) to recalculate the motor constant.
Refrain from change the setting value suddenly (within 10%). Inverter may overvoltage trip due to the rapid change of output voltage.
Voltage compensation gain and slip compensation gain – Using parameters A046 and A047, you can obtain better performance under automatic torque boost mode (A041=01). See following table for the concept of adjustment, including other parameters.
Symptom Adjustment Adjust item Motor torque is not enough at low speed
(The motor does not rotate at low speed)
Increase the voltage setting for manual torque
boost, step by step A042 / A242 Increase the voltage compensation gain for
automatic torque boost, step by step A046 / A246 Increase the slip compensation gain for
automatic torque boost, step by step A047 / A247 Reduce carrier frequency b083 Motor speed decreases (stalls) when a Increase the slip compensation gain for A047 / A247
100% fbase fmax A045=100 80% A045=80 V 0 0 5% voltage boost (100%=A082) A042 = 5 (%) fbase = 60Hz 30Hz V 100% 1.8Hz A043 = 3 (%) Hz A
3−25
load is given to the motor automatic torque boost, step by step Motor speed increases when a load is
given to the motor
Decrease the slip compensation gain for
automatic torque boost, step by step A047 / A247 The inverter trips due to overcurrent when
a load is given to the motor
Decrease the voltage setting for manual
torque boost, step by step A042 / A242 Decrease the voltage compensation gain for
automatic torque boost, step by step A046 / A246 Decrease the slip compensation gain for
automatic torque boost, step by step A047 / A247
“A” Function Run
Mode Edit
Defaults Func.
Code Name Description Lnitial data Units
A041 Torque boost select Two options:
00…Manual torque boost
01…Automatic torque boost
U
00 −A241 Torque boost select, 2nd motor
U
00 −A042 Manual torque boost value Can boost starting torque between 0 and 20% above normal V/f curve,
range is 0.0 to 20.0%
1.0 %
A242 Manual torque boost value,
2nd motor 1.0 %
A043 Manual torque boost
frequency
Sets the frequency of the V/f breakpoint A in graph (top of previous page) for torque boost,
range is 0.0 to 50.0%
5.0 %
A243 Manual torque boost
frequency, 2nd motor
5.0 %
A044 V/f characteristic curve Six available V/f curves;
00…Constant torque
01…Reduced torque (1.7)
02…Free V/F
03…Sensorless vector (SLV)
U
00 −A244 V/f characteristic curve,
2nd motor
U
00 −A045 V/f gain Sets voltage gain of the
inverter, range is 20. to 100.% 100. %
A245 V/f gain, 2nd motor 100. %
a046 Voltage compensation gain
for automatic torque boost Sets voltage compensation gain under automatic torque boost, range is 0. to 255.
100. −
a246 Voltage compensation gain
for automatic torque boost, 2nd
motor
100. −
a047 Slip compensation gain for
automatic torque boost Sets slip compensation gain under automatic torque boost, range is 0. to 255.
100. −
a247 Slip compensation gain for
automatic torque boost, 2nd
motor