L: Protection Function; L1: Motor Protection - YASKAWA CR700 Technical Manual

11.9

L: Protection Function

L parameters set the following functions.
• Motor Overload Protection
• Operation During Momentary Power Loss
• Stall Prevention
• Speed Detection
• Torque Limit
• Hardware Protection

L1: Motor Protection

◆
L1 parameters set the motor overload protection function.
Motor Protection Using Positive Temperature Coefficient (PTC) Thermistors
■
The temperature resistance characteristics of three PTC thermistors in the motor stator winding protect the motor
from overheat.
The PTC thermistors must have the characteristics in motor 1 phase as shown in the following graph.
When the PTC input signal input to the drive is more than the overload alarm level, the drive detects oH3 [Motor
Overheat (PTC Input)]. The drive continues the operation set in L1-03 [Motor Thermistor oH Alarm Select].
The overheat fault level triggers an oH4 [Motor Overheat Fault (PTC Input)] fault, and outputs a fault signal. The
drive outputs a fault signal, and stops the motor with the stop method set in L1-04 [Motor Thermistor oH Fault
Select].
Note:
PTC is an acronym for Positive Temperature Coefficient.
The following figure shows the setting procedure when you use terminal A3.
1. Connect the PTC thermistor input from the motor to analog input terminal A3 on the drive.
2. Set drive DIP Switch S4 to PTC.
YASKAWA SIEPC71061723A YASKAWA AC Drive CR700 Technical Manual
Figure 11.85 PTC Thermistor Temperature and Resistance
Figure 11.86 Connect Motor PTC
11.9 L: Protection Function
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