Cleveland Range inverter Parameter Description FU1, FU1-50 Electronic Thermal Motor i2t Selection

Chapter 4 - Parameter Description [FU1]

FU1-50: Electronic Thermal (Motor i2t) Selection

FU1-51: Electronic Thermal Level for 1 Minute

FU1-52: Electronic Thermal Level for Continuous

FU1-53: Electronic Thermal Characteristic (Motor type) Selection

These functions are to protect the motor from overheating without using additional thermal overload relay. Inverter calculates the temperature rise of the motor using several

Load Current [%]

FU1-51 [ETH 1min]

FU1-52 [ETH cont]

1 minute

Trip Time

parameters and determines whether or not the motor is overheating. Inverter will turn off its output and display a trip message when the electronic thermal feature is activated.

This function activates the ETH parameters by setting ‘Yes’.

This is the reference current when the inverter determines the motor has overheated. Inverter trips in 1 minute when 150% of rated motor current established in FU2-33 flows for 1 minute.

☞Note: The set value is the percentage of FU2-33 [Rated Motor Current].

This is the current at which the motor can run continuously. Generally, this value is set to ‘100%’ and which means the rated motor current set in FU2-33. This value must be set less than FU1-51 [ETH 1min].

☞Note: The set value is the percentage of FU2-33 [Rated Motor Current].

[Motor i2t Characteristic Curve]

To make the ETH function (Motor i2t) work correctly, the motor cooling method must be selected correctly according to the motor.

[Self-cool] is a motor that has a cooling fan connected directly to the shaft of the motor. Cooling effects of a self-cooled motor decrease when a motor is running at low speeds. The motor current is derated as the motor speed decreases.

[Forced-cool] is a motor that uses a separate motor to power a cooling fan. As the motor speed changes, the cooling effect does not change.

Output Current

Forced-Cool

100%
95%
	Self-Cool
65%
20Hz	60Hz

[Load Current Derating Curve]

☞Note: Despite the motor current changing frequently due to load fluctuation or acceleration and deceleration, the inverter calculates the i2t and accumulates the value to protect the motor.

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