Hitachi J300U Series - Manual (Page 120)

A-8
2. Energy conservation running
[Outline of the function]
This is a function for automatically setting the output voltage corresponding to the load during
the V/F control running and suppressing useless power.
The function is effective for a load of reduced torque characteristics such as a fan and pump.
When the load of an induction
motor is constant as shown in the
drawing on the right, there is a
voltage at which the current is
minimized. When the current is
minimized, the power is also
minimized. The function auto-
matically searches this voltage.
2. The function is performed
under comparatively slow
control. Therefore, when a
sudden load change (such as
an impact load) occurs, the
motor may stall.
[Precautions]
1. The output voltage is decreased so as to minimize the current. The search limits are the
voltage of torque constant characteristic ±50%.
➤
Large load
I
O
V
1
V
2
V
➤
Range where the energy
conservation is effective
V
O f
50%
100%