Filter
Top Products
61
Basic Functions
3
INVERTER FUNCTIONS
3.3.6 Electronic thermal O/L relay (Pr. 9)
*0.1K to 0.75K are set to 85% of the rated inverter current.
<Setting>
•Set the rated current [A] of the motor.
(Normally set the rated current value at 50Hz if the motor has both 50Hz and 60Hz
rated currents.)
•Setting "0" in Pr. 9 disables the electronic thermal O/L relay (motor protective
function). (The protective function of the inverter is activated.)
•When using a Mitsubishi constant-torque motor, first set "1" in Pr. 71 "applied motor"
to choose the 100% continuous torque characteristic in the low-speed range. Then,
set the rated motor current in Pr. 9 "electronic thermal O/L relay".
3.3.7 DC injection brake (Pr. 10, Pr. 11, Pr. 12)
Set the current of the electronic overcurrent protection to protect the motor from
overheat. This feature provides the optimum protective characteristics, including
reduced motor cooling capability, at low speed.
Parameter Name Factory Setting Setting Range
9 Electronic thermal O/L relay
Rated output
current*
0 to 50A
CAUTION
•
When two or more motors are connected to the inverter, they cannot be
protected by the electronic overcurrent protection. Install an external thermal
relay to each motor.
•
When the difference between the inverter and motor capacities is large and
the setting is small, the protective characteristics of the electronic
overcurrent protection will be deteriorated. In this case, use an external
thermal relay.
•
A special motor cannot be protected by the electronic overcurrent protection.
Use an external thermal relay.
♦
♦♦
♦
Related parameters
♦
♦♦
♦
•When constant-torque motor is used ⇒ Pr. 71 "applied motor" (Refer to page 70.)
By setting the DC injection brake
voltage (torque), operation time
and operation starting
frequency, the stopping
accuracy of positioning
operation, etc. or the timing of
operating the DC injection brake
to stop the motor can be
adjusted according to the load.
Pr.10
"Operation
frequency"
Output frequency (Hz)
Time
D
C
i
njection
b
rake
v
oltage
Pr.12
"Operation
voltage"
Time
Pr.11 "Operation time"