Hitachi L100 Series Instruction Manual page 95

3–24
"B" Group: Fine Tuning Functions
Electronic Thermal Overload Alarm Setting
The thermal overload detection protects the
inverter and motor from overheating due to
an excessive load. It uses a current/inverse
time curve to determine the trip point.
First, use B_13 to select the torque charac-
teristic that matches your load. This allows
the inverter to utilize the best thermal
overload characteristic for your application.
The torque developed in a motor is directly
proportional to the current in the windings,
which is also proportional to the heat generated (and temperature, over time). Therefore,
you must set the thermal overload threshold in terms of current (amperes) for parameter
B_12. The range is 50% to 120% of the rated current for each inverter model. If the
current exceeds the level you specify, the inverter will trip and log an event (error E05) in
the history table. The inverter turns the motor output OFF when tripped.
Func. Name /
Code SRW Display
B_12 Level of electronic
thermal setting
E-THM LVL 03.00A
B_13 Electronic thermal
characteristic
E-THM CHAR
WARNING: When parameter B_12, level of electronic thermal setting, is set to device
FLA rating (Full Load Ampere nameplate rating), the device provides solid state motor
overload protection at 115% of device FLA or equivalent. Parameter B_12, level of
electronic thermal setting, is a variable parameter.
NOTE: For inverter models 005NFE, 011NFE, and 030HFE, the thermal value is less
than the rated amperes (is the same as models 004NFE, 007NFE, and 040HFE respec-
tively). Therefore, be sure to set the electronic thermal overload according to the actual
motor driven by the particular inverter.
"B" Function
Description
Set a level between 50% and
120% for the rated inverter
current.
Select from two curves, option
codes:
00 ...Reduced torque
CRT
01 ...Constant torque
Torque
Constant torque
100%
80%
Reduced
torque
60%
B_13 = 00
0
5 20 60
Output frequency
Run
Mode
–FE –FU
Edit
(CE) (UL)
✘
Rated current for each
inverter model
*See note
✘
01
B_13 = 01
Hz
120
Defaults
–FR
Units
(Jpn)
%
01 00 —