Hitachi NES1-002LB, Quick Reference Manual

Page: 84 / 295

Chapter 7 Explanation of Functions
7 - 9
7.2.7 Base frequency setting
(1) Base frequency and motor voltage
- With the base frequency setting and AVR voltage select
functions, adjust the inverter outputs (frequency and
voltage) to the motor ratings.
- The base frequency is the nominal frequency of the motor.
Set a base frequency that meets the motor specification.
Carefully note that setting the base frequency to less than
50 Hz may result in motor burnout.
- A special motor requires a base frequency of 60 Hz or
more. Your inverter model may not be suitable for such a
special motor, and one with a larger capacity may be
required.
- Select the motor voltage that meets the motor specification. Selecting a motor voltage exceeding the
motor specification may result in motor burnout.
- To switch the base frequency among the 1st and 2nd settings, assign function "08" (SET) to intelligent
input terminals . Use the SET signal for switching.
Item Function code Range of data Description
Base frequency
setting
A003/A203
30. to maximum frequency,
1st/2nd motors (Hz)
AVR voltage select A082/A282
200/215/220/230/240 Selectable on 200 V class inverter models
380/400/415/440/460/480 Selectable on 400 V class inverter models
7.2.8 Using the AVR Functions
(1) What's the AVR function?
The AVR function maintains the correct voltage output to the motor, even when the voltage input to the
inverter fluctuates. The output voltage maintained by this function is based on the voltage specified by
the motor voltage select(A082/A282). But it can not exceed the receiving voltage.
Use the AVR function select (A081/A281) to enable or disable the AVR function.
(2) AVR filter time constant and AVR deceleration gain
Motor acts as a generator during deceleration. Therefore, energy is regenerated to the inverter. As a result,
the DC voltage of the inverter is increased. If DC voltage exceeds overvoltage level, the inverter is
generated the overvoltage trip.
The higher the output voltage of the inverter, energy is consumed by the increasing loss of the motor.
Therefore, it is possible to shorten the deceleration time. (However, the burden of the motor is increased.)
In order to shorten the deceleration time without tripping the overvoltage,
1. Set A081 = 02.
2. Please tune voltage characteristics using the A084 and A083.
Base frequency
Output frequency
(Hz)
Output
voltage
AVR voltage
select
(100%)