3 electronic, Thermal overload, 4 klixon – GE Industrial Solutions AF-650 GP General Purpose Drive Programming Guide User Manual

Page 36: 3 electronic thermal overload

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Illustration 3.9 KTY Type Selection

KTY Sensor 1: 1 k

Ω at 100 °C (e.g. Philips KTY 84-1)

KTY Sensor 2: 1 k

Ω at 25 °C (e.g. Philips KTY 83-1)

KTY Sensor 3: 2 k

Ω at 25 °C (e.g. Infineon KTY-10

NOTE

If the temperature of the motor is utilized through a
thermistor or KTY sensor the PELV is not complied with in
case of short circuits between motor windings and sensor.
In order to comply with PELV the sensor must be extra
isolated.

3.3.3.3 Electronic Thermal Overload

The calculations estimate the need for a lower load at
lower speed due to less cooling from the fan incorporated
in the motor.

Illustration 3.10 Electronic Thermal Overload Profile

3.3.3.4 Klixon

The Klixon type thermal circuit breaker uses a KLIXON

®

metal dish. At a predetermined overload, the heat caused
by the current through the disc causes a trip.

Using a digital input and 24 V as power supply:
Example: The frequency converter trips when the motor
temperature is too high
Parameter set-up:
Set F-10 Electronic Overload to [2] Thermistor Trip
Set F-12 Motor Thermistor Input to [6] Digital Input

Illustration 3.11 Thermistor Connection

F-11 Motor External Fan

Option:

Function:

[0]

*

No

No external fan on motor, i.e. the motor is derated at

low speed.

[1]

Yes Applies an external motor fan (external ventilation), so

no derating of the motor is required at low speed. The

upper curve in graph above (fout = 1 x fM,N) is

followed if the motor current is lower than nominal

motor current (see P-03 Motor Current). If the motor

current exceeds nominal current, the operation time

still decreases as if no fan were installed.

Parameter Descriptions

AF-650 GP Programming Guide

DET-618C

35

3

3

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