Mitsubishi Electric FATEC FR-A800 Manual page 75

5
BREAKDOWN MAINTENANCE
Electronic thermal O/L relay operation characteristic (THM)
This function detects the overload (overheat) of the motor and stops the operation of the
output transistor in the inverter to stop the output. (The operation characteristic is shown on
the left.)
• Set the rated current value of the motor (A) in H000 (Pr.9).
(If the motor has both 50 Hz and 60 Hz ratings and G001 (Pr.3) Base frequency is set to
"60 Hz", set the 60 Hz rated motor current multiplied by 1.1 times.)
• Set "0" in H000 (Pr.9) to avoid activating the electronic thermal O/L relay; for example,
when using an external thermal relay for the motor. (Note that the output transistor
protection of the inverter is activated. (E.THT))
1
2
3
4
5.2 Troubleshooting by the demonstration machine
70
H000 (Pr.9) = 50% setting
of inverter rating ∗1, 2
70
30 Hz
or more
∗3
20 Hz
60
10 Hz
6 Hz
0.5 Hz
50
240
180
120
60
105%
52.5%
100
50
Inverter output power (%)
(% to the inverter rated current)
When 50% of the inverter rated current (current value) is set in H000 (Pr.9.)
The % value denotes the percentage to the inverter rated current. It is not the percentage to the rated motor
current.
When the electronic thermal O/L relay function dedicated to the Mitsubishi constant-torque motor is set, this
characteristic curve applies to operation at 6 Hz or higher.
Transistor protection is activated depending on the temperature of the heat sink. The protection may be
activated even with less than 150% depending on the operating conditions.
H000 (Pr.9) = 100% setting
of inverter rating ∗2
30 Hz or more
∗3
20 Hz
Operation region
10 Hz Region on the right of
characteristic curve
6 Hz
Non-operation region
Region on the left of
0.5 Hz
characteristic curve
Characteristic when electronic thermal relay
function for motor protection is turned off
(When H000 (Pr.9) setting is 0 (A))
Range for
the transistor
protection ∗4
150 230