Mitsubishi Electric 800 Series Instruction Manual page 202

• While the RT signal is ON, the setting values of Pr.51 is referred to provide thermal protection. (While the RT signal is ON,
the setting values of Pr.9 is referred to provide thermal protection under PM sensorless vector control.)
Pr.450 Pr.9
Second applied Electronic thermal
motor O/L relay
9999 0
9999 Other than 0
Other than 9999 0
Other than 9999 Other than 0
NOTE
• The RT signal is the Second function selection signal. The RT signal also enables other second functions. (Refer to
• For the RT signal, set "3" in any parameter from Pr.178 to Pr.189 (Input terminal function selection) to assign the function.
 Electronic thermal O/L relay pre-alarm (TH) and warning signal (THP
signal)
• If the accumulated electronic thermal value reaches 85% of the Pr.9 or Pr.51 setting, electronic thermal O/L relay function
pre-alarm (TH) is displayed and the electronic thermal O/L relay pre-alarm (THP) signal is output. If the value reaches
100% of the Pr.9 setting, the motor thermal protection (E.THM/E.THT) is activated to shut off the inverter output. The
inverter output is not shut off with the TH display.
• 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).
Pr.51
Second electronic thermal
O/L relay
9999
0
0.01 to 500 (0.1 to 3600)
9999
0
0.01 to 500 (0.1 to 3600)
9999
0
0.01 to 500 (0.1 to 3600)
9999
0
0.01 to 500 (0.1 to 3600)
100%
85%
ON ON
Time
RT signal OFF
Second
First motor
monitor
× ×
× ×
× Δ
○ ×
○ ×
○ Δ
× ×
× ×
× Δ
○ Δ
○ ×
○ Δ
○: Values are accumulated by using the output current.
Δ: Values are accumulated by assuming the output
current is 0 A (cooling processing).
×: Electronic thermal O/L relay does not operate.
10. (H) Protective Function Parameters
10.1 Motor overheat protection (electronic thermal O/L relay)
RT signal ON
Second
First motor
monitor
× ×
× ×
× ○
○ ×
Δ ×
Δ ○
× ×
× ×
× ○
Δ ○
Δ ×
Δ ○
page 289.)
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