YASKAWA G7 Series Technical Manual page 273

PTC Thermistor Characteristics
The following diagram shows the characteristics of the PTC thermistor temperature to the resistance value.
Resistance (ohms)
1330
550
Fig 6.40 PTC Thermistor Temperature-Resistance Value Characteristics
Operation during Motor Overheating
Set the operation if the motor overheats in parameters L1-03 and L1-04. Set the motor temperature input filter
time parameter in L1-05. If the motor overheats, the OH3 and OH4 error codes will be displayed on the Digi-
tal Operator.
Error Codes If the Motor Overheats
Error Code
OH3 Drive stops or continues to operate, according to the setting in L1-03.
OH4 Drive stops according to the setting in L1-04.
By setting H3-09 (Multi-function Analog Input Terminal A2 Function Selection) or H3-05 (Multi-function
Analog Input Terminal A3 Function Selection) to E (Motor temperature input), you can detect alarm OH3 or
OH4 using the PTC temperature-resistance characteristics, and protect the motor. The terminal connections
are shown in the following diagram.
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Class H
Class F
180°C
150°C
Tr: Temperature threshold value
Temperature
Tr Tr+5
Details
Machine Protection
6-
55