Hitachi SJ Series, User Manual

Page: 200 / 786

12-7-1
Chapter 12 Inverter Functions
12.7 Temperature protection of motor
12.7.1 Electronic thermal setting
of motor
• Want to make thermal protection of motor
• Want to change the protection level in accordance
with the motor rated voltage.
Change of electronic thermal level of motor
• Setting in accordance with the motor rated current
protects continuous flow of current in the motor. To
make the protection earlier, the protection level
should be set lower than the motor rated current.
(Ex. 1) Motor rated current 64A ([bC110]=64.0A)
Setting range:12.8A(20%)~204.0A(300%)
When driven at a base frequency
Parameters
*1) The inverter rated current is switched by the load
type selection [Ub-03]. Even if [bC110] is set to be
high, [E001] excessive current error occurs when
the current exceeds the excess current level.
• Make the setting correctly as this is necessary to
protect the motor.
• When the thermal protection begins, [E005] motor
electronic thermal error occurs.
• Irrespective of the thermal setting of the motor, the
inverter electronic thermal protection works
independently to protect the inverter.
• When the current grows rapidly, [E001] excessive
current error could occur before [E005] motor
electronic thermal error.
• Even electronic thermal level is set high, electronic
thermal for inverter itself works separately, at
frequency decreased from 5Hz and 80% at 0Hz.
• The electronic thermal time-limited characteristics
is shown in (Ex. 1) when the first electronic thermal
level [bC110] is 64A
• Example 1 shows the case of reduction ratio x1.
(For example, the case of the motor driven at a
base frequency for [bC111]=01.)
• The magnification ratio and hence the time to a trip
could change depending on the choice of the
electronic thermal characteristic.
• A trip occurs in 60 s when an electric current of
150% of the electronic thermal level x1 flows
continuously.
Item Parameters Data Description
First electronic
thermal
level
[bC110]
In range of 20-300% of the
inverter rated current (unit: A) *1) Sets the protection current of
motor.
First electronic
thermal
characteristics
selection
[bC111]
00
Reduced torque characteristics:
Pattern for cooling function
deterioration at a low speed
01
Constant torque characteristics:
Pattern for constant output
02
Free setting:
Multiple patterns are available
according to the motor
characteristics.
Ｑ
Ａ
！
Ａ
Output current (A)
(Ratio to ND
rated current)
Trip time (s)
60
3.00
.5
69.8
(109%)
0
96
(150%)
128
(200%)