Hitachi WJ Series User Manual page 119

Chapter 8
■ Motor Capacity and Number of Poles
!
 For induction motors, if "Async. Motor capacity [H003]
*1
[H004] " is changed, the motor constant parameter setting values will be written to the motor
constants of the Hitachi standard motor stored in advance. Accurate setting of capacity and
number of poles may prevent the motor from being disturbed, or stabilize the motor drive.
(The motor constant parameters here indicate the motor constant parameters when the "Async.
Motor constant selection [H002]
Motor Constant" for more information.)
 When the control method is V/f control (constant torque characteristics (VC), reduced torque
characteristics, and free V/f characteristics) and multiple motors are driven by a single inverter,
set a value close to the total motor capacity to the motor capacity.
 Refer to "8.3.1 Procedure for Auto-tuning of an Induction Motor" for motor constant settings.
■ Relationship between frequency and voltage in general V/f control
 When the base frequency and rated voltage are
set, the voltage output in general V/f control is
as shown in the figure on the right.
 The output voltage from the base frequency to
the maximum frequency reaches the motor
rated voltage at the maximum. The maximum
frequency setting value is set by the maximum
value of the analog external input (e.g. 10 VDC
from 0 to 10 VDC).
 When an induction motor is used with more
than 60 Hz of base frequency, it is a special
motor. For this reason, the maximum applicable
motor of the inverter may differ and it may be necessary to use bigger capacity inverter.
 If there is no selection in the "Async. Motor rated voltage [A082]
voltage, set the closest and higher value. For induction motors, set the "Output voltage gain
*1
[A045] " by referring the equation below.
Output voltage gain [A045]
■ Automatic voltage regulation function (AVR function)
 The inverter automatically operates the automatic
voltage regulation function (AVR function). This
function outputs voltage to the motor correctly
even with variation in the input voltage to the
inverter.
 Even if this function is used, a voltage exceeding
the input voltage cannot be output.
 For the output voltage to the motor, see "9.9.4
Suppressing Overvoltage by Controlling Output Voltage".
■ Output current
 If the motor rated current is set above the inverter rated current, the desired characteristics may
not be satisfied. In addition, the inverter protection may be applied first.
*1. "2nd-motor control [SET]" target parameter. The second control parameter is also subject to setting.
Mandatory Setting for Motor Drive and Test Run
*1
" setting is "Hitachi Standard (00)". Refer to "8.1.5 Setting
*1 = 100% × Motor Rated Voltage / Async. Motor rated voltage [A082]
8-1-6
*1 " or "Async. Motor number of poles
Output
voltage (V)
Motor
Rated
voltage
(100%)
Base frequency
*1
" that matches the motor rated
Output voltage
Motor rated
voltage
Output voltage by AVR
function
Output
frequency
(Hz)
Maximum frequency
*1
Input voltage
Time (s)