Hitachi SJ7002 Series Instruction Manual page 215

Constant Torque Characteristic – Selecting the constant torque characteristic for the example
motor gives the curves below. At 2.5 Hz, the output current is reduced by a factor of 0.9 for
given trip times.
Trip current
reduction
factor
x 1.0
x 0.9
x 0.8
0
2.5 5
Free Thermal Characteristic - It is possible to set the electronic thermal characteristic using a
free-form curve defined by three data points, according to the table below.
Function
Name
Code
B015 / Free-setting electronic
B017 / thermal frequency 1, 2, 3
B019
B016 / Free setting electronic
B018 / thermal current 1, 2, 3
B020
The left graph below shows the region for possible free-setting curves. The right graph below
shows an example curve defined by three data points specified by B015 – B020.
Trip current
reduction
factor
x 1.0
x 0.8
Setting range
0
5
Output freq.
Suppose the electronic thermal setting (B012) is set to 44 Amperes. The graph below shows the
effect of the free setting torque characteristic curve. For example, at (B017) Hz, the output
current level to cause overheating in a fixed time period is reduced to (B018) A. Points (x), (y),
and (z) show the adjusted trip current levels in those conditions for given trip times.
Trip
time (s)
60
0.5
0
(x)
Trip
time (s)
60
0.5
Hz 0
60
Reduced trip current at 2.5 Hz
Description
Data point coordinates for Hz axis
(horizontal) in the free-form curve
Data point coordinates for Ampere
axis (vertical) in the free-form curve
Output
current (A)
B020
B018
B016
0
Hz
400
B015 B017 B019 Ax04
(x) = B018 value x 116%
(y) = B018 value x 120%
(z) = B018 value x 150%
A Reduced trip current at (B017) Hz
(y) (z)
4–53
SJ700 Inverter
2
A
47.8 62.1 82.8
104% 135% 180%
Range
0 to 400Hz
0.0 = (disable)
0.1 to 1000.
Hz
max. freq.