Chapter 12 Descriptions of Parameter SettingsMS300
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Setting the parameter to 1 is suitable for standard motor (motor fan is fixed on the rotor shaft).
For this kind of motor, the cooling capacity is lower in low speed; therefore, the action of an
electronic thermal relay reduces the action time to ensure the life of motor.
When the power is cycled frequently, if the power is switched OFF, the electronic thermal relay
protection is reset; therefore, even setting the parameter to 0 or 1 may not protect the motor
well. If there are several motors connected to one drive, install an electronic thermal relay in
each motor.
Set the parameter to 150% of motor rated current and use with the setting of Pr.06-14 and Pr.06-
28 to prevent motor damage due to overheating. When it reaches the setting, the drive displays
“EoL1 / EoL2”, and the motor coasts to stop.
Use this parameter to set the action time of the electronic thermal relay. It works based on the I2t
characteristic curve of electronic thermal relay, the output frequency and current of the drive, and
the operation time to prevent the motor from overheating.
The action of the electronic thermal relay depends on the settings for Pr.06-13 and Pr.06-27.
1. Pr.06-13 or Pr.06-27 is set to 0 (using inverter motor):
When the output current of the drive is higher than 150% of the motor rated current (refer to
the motor rated current % corresponded to the motor rated frequency in the motor cooling
curve with independent fan), the drive starts to count the time. The electronic thermal relay
acts when the accumulated time exceeds Pr.06-14 or Pr.06-28.
2. Pr.06-13 or Pr.06-27 is set to 1 (using standard motor):
When the output current of the drive is higher than 150% of the motor rated current (refer to
the motor rated current % corresponded to the motor rated frequency in the motor cooling
curve with shaft-fixed fan), the drive starts to count the time. The electronic thermal relay
acts when the accumulated time exceeds Pr.06-14 or Pr.06-28.
The actual electronic thermal relay action time adjusts according to the drive output current
(shown as the motor loading rate %). The action time is short when the current is high, and
the action time is long when the current is low. Refer to the following diagram.
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