Illustration 3.7 PTC Thermistor Connection - Digital Input
Using an analog input and 10 V as supply:
Example: The frequency converter trips when the motor
temperature is too high.
Parameter set-up:
•
Set
parameter F-10 Electronic Overload
to
[2]
Thermistor Trip
.
•
Set
parameter F-12 Motor Thermistor Input
to
[2]
Analog Input 54
.
Illustration 3.8 PTC Thermistor Connection - Analog Input
Input
digital/analog
Supply voltage
Threshold
cut out values.
Digital
10 V
<800
Ω⇒
2.7 k
Ω
Analog
10 V
<3.0 k
Ω⇒
3.0 k
Ω
Table 3.4 Threshold Cutout Values
NOTICE
Check that the selected supply voltage follows the
specification of the used thermistor element.
3.2.3.2 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 3.9 Electronic Thermal Overload Profile
3.2.3.3 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 supply:
Example: The frequency converter trips when the motor
temperature is too high.
Parameter set-up:
•
Set
parameter F-10 Electronic Overload
to
[2]
Thermistor Trip
.
•
Set
parameter F-12 Motor Thermistor Input
to
[6]
Digital Input
.
Illustration 3.10 Thermistor Connection
F-11 Motor External Fan
Option:
Function:
[0]
*
No
No external fan on motor, that is 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
(f
out
= 1 x f
M,N
) is
followed if the motor current is lower than nominal
motor current (see
). If
the motor current exceeds nominal current, the
operation time still decreases as if no fan was
installed.
Parameter Description
38
03/2016 All rights reserved.
DET-620D
3
3
