Mitsubishi Electric FR-A700 Instruction Manual page 396

Selection and protection of a motor
Electronic thermal relay function alarm output and alarm signal (THP signal)
The alarm signal (THP) is output when the electronic thermal relay function cumulative value
reaches 85% of the level set in Pr. 9 or Pr. 51. If it reaches 100% of the Pr. 9 "Electronic thermal
O/L relay" setting, electronic thermal relay function protection (E. THM/E.THT) occurs.
NOTE The prealarm signal "THP" is also issued as soon as the thermal load of the IGBT output
stages of the frequency inverter is 85%. If the load rises further up to 100%, then the thermal
overload protection of the frequency inverter responds and the "E.THT" error message is
shown.
The inverter does not shut off the output if the alarm signal is output. For the terminal used for
the THP signal output, assign the function by setting "8" (source logic) or "108" (sink logic) in any
of Pr. 190 to Pr. 196 "Output terminal function selection".
Electronic thermal O/L relay prealarm THP
Fig. 6-90: Prealarm signal output
NOTE The signal can be assigned to the input terminal using any of Pr. 190 to Pr. 196 "Output
terminal function selection". When terminal assignment is changed, the other functions may
be affected. Please make setting after confirming the function of each terminal.
External thermal relay input (OH signal)
To protect the motor against overheat, use the OH signal when using an external thermal relay
or the built-in thermal protector of the motor.
When the thermal relay operates, the inverter shuts off the output and outputs the alarm signal
(E.OHT).
For the terminal used for OH signal input, assign the function by setting "7" to any of Pr. 178 to
Pr. 189 "Input terminal function selection".
NOTE The signal can be assigned to the input terminal using any of Pr. 178 to Pr. 189 "Input
terminal function selection". When terminal assignment is changed the other functions may
be affected. Please make setting after confirming the function of each terminal.
6 - 216
Electronic thermal relay function
operation level
U
V
W
OH
PC
ON
Fig. 6-91:
Connection of an external thermal relay
M
~
3
Parameter
Time
ON
I001138E
I000553C