Mitsubishi Electric 800 Series Instruction Manual (Function page 282

• For the terminal used for the THP signal output, set "8" (positive logic) or "108" (negative logic) in any parameter from
Pr.190 to Pr.196 (Output terminal function selection).
Electronic thermal
relay function
operation level
Electronic thermal O/L
(THP)
relay alarm
OFF
NOTE
• Changing the terminal assignment using Pr.190 to Pr.196 (Output terminal function selection) may affect the other
functions. Set parameters after confirming the function of each terminal.
 External thermal relay input (OH signal, E.OHT)
Thermal relay protector
Inverter
Motor
U
V
M
W
OH
SD
External thermal relay input connection diagram
• The External thermal relay input (OH) signal is used when using the external thermal relay or the thermal protector built
into the motor to protect the motor from overheating.
• When the thermal relay is activated, the inverter output is shut off by the external thermal relay (E.OHT).
• To input the OH signal, set "7" in any parameter from Pr.178 to Pr.189 (Input terminal function selection) to assign the
function.
• Vector-control-dedicated motors (SF-V5RU) are equipped with thermal protectors.
Inverter SF-V5RU
∗1
PC
2W1kΩ G1
OH
G2
SD
Connecting the SF-V5RU thermal protector
*1 Connect the recommended 2 W 1 kΩ resistor between terminals PC and OH. (Refer to the Instruction Manual (Connection).)
NOTE
• Changing the terminal assignment using Pr.178 to Pr.189 (Input terminal function selection) may affect the other functions.
Set parameters after confirming the function of each terminal.
 PTC thermistor input (Pr.561, Pr.1016, E.PTC)
This function is used to protect the motor from overheating by inputting outputs from the motor's built-in PTC thermistor to the
inverter. It is recommended that a PTC thermistor whose resistance increases most rapidly around the rated activating
temperature (TN±DT) is used.
Inverter
PTC thermistor input connection diagram
100%
85%
ON
ON
Time
Motor
U
V
W
10
2
Temperature - resistance
Thermistor resistance
Thermistor curve
R2
Pr.561
R1
TN-DT TN+DT
existing range
TN
TN: Rated operating temperature
Example of PTC thermistor characteristics
12. (H) Protective Function Parameters
12.1 Motor overheat protection (electronic thermal O/L relay)
Thermistor temperature
281
11
12
13
14
15
16
17
18
19
20