YASKAWA F7 Programming Manual page 110

10V
A1 Voltage
Factory Default
Function: Motor Temperature
Setting: E
In addition to or in place of the OL1 (Motor Overload) fault of the Drive, it is possible to use a PTC (Positive Temperature
Coefficient) thermistor for motor insulation protection. The PTC thermistors are built into the windings of some motors and
will vary their resistance based on temperature. An example PTC characteristic is show below.
Connection of the thermistor to the Drive is shown below, in addition make sure Dip Switch S1-2 is in the OFF position, see Figure 55.
Branch resistance
*1
18 k Ω
PTC Thermistor
*1
using a 3-phase PTC with the characteristics shown in
the figure below.
H3-02
H3-03
With H3-03 applied
Fig. 71 Frequency Bias 2 Applied to Analog frequency reference
Resistance (ohms)
1330
550
Tr 5
Fig. 72 PTC Thermistor Temperature-Resistance Value Characteristics
The resistance value of 18 k Ω is only valid for
above.
Fig. 73 Thermistor To Drive Connection Diagram
A1 Voltage
10V
Class H
Class F
180
150
Tr: Temperature threshold value
Temperature
Tr
Tr Tr+5
+V
(+15 V, 20 mA)
A2
(0-10 Vdc)
Rbranch
AC
Programming 102
H3-02
H3-03
10V
With both H3-03 and analog input bias
(H3-09=0) applied
(H3-09=D) applied
( R x3) x ( V -V
ptc@Tr S ptc@OH3
=
V
ptc@OH3
A1 Voltage
)