TECO L510S Series - Page 113

4-68

RinRR
RinR
V
PTC
PTC
//
//
10
2
1


 Selection for motor overheat protection:
PTC (Positive temperature coefficient) sensors are used in motor windings to provide additional
motor protection from overheat.
PTC thermistor can be connected to terminals AVI and AGND.
A voltage divider resistor R is necessary to be connected as shown below in figure (b).
1) If 08-10 =1 or 2 (Decelerate or Cost to stop on over temperature detection). When over
temperature is detected by signal at terminal AVI increasing above the warning detection limit
set in parameter 08-15 and the delay time set in parameter. 08-12 is reached, the display will
show ”OH4”( motor over heat detection), then output frequency will decelerate or coast to
stop according to the selection 1 or 2.
2) If 08-10 = 3 Continue running when warning level is reached.(08-15). Coast to stop when
protection level is reached.(08-13).When over temperature is detected by signal at terminal
AVI increasing above the Warning detection limit set in parameter 08-15, then the display will
show “OH3”(motor over heat warning level) and the motor will continue to run.
If temperature detected increases above the set limit in parameter 08-13 and for the delay
time set in parameter 08-12 then the display will show “OH4” (motor over heat detection), and
the motor will coast to stop.
3) Motor over heat detection “OH4” can be reset when the temperature detection level at
terminal AVI becomes lower then the set level in parameter【08-14 PTC reset level】.
4) External PTC thermistor characteristics
Diagram in 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℃: R
PTC≦ 550Ω, put value of RPTC into formula to calculate the value of V to be set
in parameter【08-14 PTC reset level】.
Tr＋ 5℃: R
PTC≧1330Ω, put value of RPTC into formula to calculate, the value of V to be
set in parameter【08-13 PTC protection level】.
5) For different specifications of PTC thermistor, set the values for parameters 08-13 and 08-14
by calculating from the formula shown below.
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
(1~2k ohm)
R
PTC
10V
AVI
GND
Internal
circuit
Rin
**
Frame1&Frame2: Rin=164k ohm
Frame3&Frame4: Rin=204k ohm