4-63
4) External PTC thermistor characteristics
Figure (a) shows two curves for Class F and Class H temperatures.
Tr = 150°C in class F,
Tr = 180°C in class H.
Tr - 5°C:RPTC≦ 550Ω, put value of RPTC into formula(1) to calculate the value of V to be set in
parameter【08-14 PTC reset level】.
Tr+ 5°C:RPTC≧1330Ω, put value of RPTC into formula (1) to calculate, the value of V to be set in
parameter【08-13 PTC protection level】.
5) For different specifications of PTC thermistors, set the values for parameters 08-13 and 08-14 using
the formula below.
155//
155//
10
2
1
PTC
PTC
RR
R
V
……………….formula (1)
Fan Control Temperature Level
When 08-07=【0】 (Heat sink temperature dection control for cooling fan). Fan will run when temperature of
heatsink rises above temperature set in 08-16;
When temperature of heatsink falls below ”setting value of 08-16 - 20°C”, fan will stop.
1330
550
Resistance
(ohms)
Temperature
Class F
150°C
Class H
180°C
Tr'
Tr - 5
Tr
Tr + 5
Tr:Temperature threshold
value
(a) PTC Thermistor
Characteristics
(b) PTC Thermistor
Connections
R
RPTC
+
10V
AVI
GND
Internal
circuit
155KΩ