Mitsubishi Electric FR-A820-00046 (0.4K), Instruction Manual

Page: 508 / 1218

(H) Protective function parameter Parameters
5 - 306
Electronic thermal O/L relay when using IPM motor (Pr. 9, E.THM)
●
This function detects the overload (overheat) of the motor and trips the inverter by stopping the
operation of the transistor at the inverter output side. (The operation characteristic is shown
below.)
●
Set the rated current (A) of the motor in Pr. 9. Performing IPM parameter initialization automati-
cally sets the rated current of the IPM motor. (Refer to page 5-78.)
●
Set "0" in Pr. 9 to avoid activating the electronic thermal O/L relay function; for example, when
using an external thermal relay for the motor.
(Note that the output transistor protection of the inverter is activated. (E.THT))
*
The % value denotes the percentage to the rated motor current.
– Protective function activated area: the area right of the characteristic curve
– Normal operation area: the area left of the characteristic curve
I002580E
Fig. 5-122: Electronic thermal relay function operation characteristic (MM-CF)
NOTES The internal accumulated heat value of the electronic thermal relay function is reset to the initial
value by the inverter's power reset and reset signal input. Avoid unnecessary reset and power-
OFF.
When using a PM motor other than MM-CF, set the free thermal parameters (Pr. 600 to Pr. 604) in
accordance with the motor characteristic.
The transistor protection thermal O/L relay is activated early when the Pr. 72 "PWM frequency
selection" is increased.
80 100 120 140 160 200 220 240 260 280 300
50
60
70
0
60
120
180
240
2000 r/min
(133.33 Hz) or lower
3000 r/min
(200 Hz)
2000 r/min
(133.33 Hz) or lower
3000 r/min
(200 Hz)
Range for the
transistor
protection
Current [%]
T
h
ermal
r
e
la
y oper
a
tion time [s]
(s) u
n
it displ
a
y
in this region
(min) unit displa
y
in
this r
e
gion
Th
e
rm
a
l rel
a
y
operation time
[min]