Toshiba TOSVERT VF-A7 Instruction Manual page 2

3. Reference excitation current characteristic
f481 =0,2
Reference excitation
current [multiple]
1.5
1.0
0
3Hz(fixed)
*3 : α is a coefficient between 0 and 1. It is 1 at 3Hz, while it is 0 at the frequency at point *4 shown above.
*4 : The operation frequency at this point varies depending on the vl setting and the motor characteristics. For example, if vl is
set at 60Hz and the motor capacity is 200V-3.7kW, the frequency at this point is approximately 45Hz.
4. How to set the parameter
a) If the default settings allow the motor to produce enough torque, there will be no need to change
the settings of these parameters.
b) If you want to decrease the excitation current when no load is applied, set f481 to 1 and
decrease the setting of f480 to bring the current down to the desired level.
c) If a brake is applied at the start of operation, set f480 to 0 and f481 to 1 so that the
excitation current will not be boosted.
d) When the overcurrent occurs in a start and a low-speed driving, set f481 to 2 or 3.
1+0.5×α
*3
Operation
frequency
Base
*4
[Hz]
frequency
(vl)
f481 =1,3
Reference excitation
current [multiple]
f480
1+
128
1.0
0
3Hz(fixed)
- 2E -
E6581179
f480
1+
α *3
×
128
Operation
frequency
Base
*4
[Hz]
frequency
(vl)
②