L: Protection Function; L1: Motor Protection - YASKAWA GA700 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
• Auto Restart
• Detection of Overtorque/Undertorque
• Torque Limit
• Hardware Protection
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L1: Motor Protection

L1 parameters set the motor overload protection function.
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Motor Protection Using Positive Temperature Coefficient (PTC) Thermistors
The motor is protected from overheating through the use of temperature resistance characteristics of three PTCs
thermistors that are built into the motor stator winding.
The PTC thermistors must exhibit the characteristics in motor 1 phase as illustrated in the following graph.
When the PTC input signal input to the drive exceeds the overload alarm level, oH3 [Motor Overheat Alarm (PTC
Input)] flashes on the keypad. The drive continues the operation selected in L1-03 [Motor OH Alarm Operation
Select].
The overheat fault level triggers anoH4 [Motor Overheat Fault (PTC Input)] fault, and outputs a fault signal. The
drive outputs a fault signal, and stops the motor using the stop method selected in L1-04 [Motor OH Fault
Operation Select].
Note:
PTC is an acronym for Positive Temperature Coefficient.
The following figure illustrates the configuration procedure when terminal A3 is used.
1. Connect the PTC thermistor input from the motor to analog input terminal A3 on the drive.
YASKAWA ELECTRIC SIEP C710617 01B YASKAWA AC Drive GA700 Technical Manual
Figure 11.117 PTC Thermistor Temperature and Resistance
11.9 L: Protection Function
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