Hitachi SJ Series, User Manual

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12-7-3
Chapter 12 Inverter Functions
Constant torque electronic thermal
• Use this setting to use the constant-torque motor
(Ex. 3) For induction motor rated current: 64A,
[bC110]=64(A)
Base frequency [Hb104]=50Hz, output frequency
=5Hz
Free electronic thermal characteristics
• To protect the motor, the electronic thermal
characteristics can be freely set in accordance
with the load.
Parameters
*1) The inverter rated current is switched by the load
type selection [Ub-03].
• When the first electronic thermal level [bC110] is
64 A, the reduction ratio is ×0.9 for operations at a
base frequency of 60 Hz and output frequency of
2.5 Hz and the electronic thermal time-limited
characteristics are given in the lower part of
Example 3.
• Since Example 1 shows the case of the reduction
ratio ×1, a trip occurs in 60 s when an electric
current of 150% ×1 of the ND rated current flows
continuously. However in Example 3, a trip occurs
in 60 s when an electric current of
150%×0.9=135% of the ND rated current flows
continuously.
Item Parameters Data Description
Free electronic
thermal frequency 1
[bC120] 0.00~[bC122](Hz)
Frequency corresponding to free
electronic thermal current 1
Free electronic
thermal current 1
[bC121] Inverter rated current x 0-300% (A) *1)
Current corresponding to free
electronic thermal frequency 1
Free electronic
thermal frequency 2
[bC122] [bC120]~[bC124](Hz)
Frequency corresponding to free
electronic thermal current 2
Free electronic
thermal current 2
[bC123] Inverter rated current x 0-300% (A) *1)
Current corresponding to free
electronic thermal frequency 2
Free electronic
thermal frequency 3
[bC124] [bC122]~590.00(Hz)
Frequency corresponding to free
electronic thermal current 3
Free electronic
thermal current 3
[bC125] Inverter rated current x 0-300% (A) *1)
Current corresponding to free
electronic thermal frequency 3
Ａ
Reduction
ratio
Inverter
Output frequency
(Hz)
X1.0
0 50
70.4
(110%)
96
(150%)
128
(200%)
Motor current (A)
(Ratio to motor rated
current)
60
3
0
Trip time (s)
×1
0 60
Base frequency