Delta VFD-E Series - Page 175

Chapter 4 Parameters 
4-120
 If temperature exceeds the setting level, motor will be coast to stop and is
displayed. When the temperature decreases below the level of (Pr.07.15-Pr.07.16) and
stops blinking, you can press RESET key to clear the fault.
 Pr.07.14 (overheat protection level) must exceed Pr.07.15 (overheat warning level).
 The PTC uses the AVI-input and is connected via resistor-divider as shown below.
The voltage between +10V to ACM: lies within 10.4V~11.2V.
The impedance for AVI is around 47kΩ.
Recommended value for resistor-divider R1 is 1~10kΩ.
Please contact your motor dealer for the curve of temperature and resistance value for PTC.
A
VI
A
CM
+10V
PTC
VFD-E
47k Ω
resistor-divider
R1
internal circuit
 Refer to following calculation for protection level and warning level.
Protection level
Pr.07.14= V
+10
* (R
PTC1
//47K) / [R1+( R
PTC1
//47K)]
Warning level
Pr.07.16= V
+10
* (R
PTC2
//47K) / [R1+( R
PTC2
//47K)]
Definition:
V+10: voltage between +10V-ACM, Range 10.4~11.2VDC
RPTC1: motor PTC overheat protection level. Corresponding voltage level set in Pr.07.14,
RPTC2: motor PTC overheat warning level. Corresponding voltage level set in Pr.07.15,
47kΩ: is AVI input impedance, R1: resistor-divider (recommended value: 1~20kΩ)
 Take the standard PTC thermistor as example: if protection level is 1330Ω, the voltage
between +10V-ACM is 10.5V and resistor-divider R1 is 4.4kΩ. Refer to following calculation
for Pr.07.14 setting.
1330//47000=(1330*47000)/(1330+47000)=1293.4
10.5*1293.4/(4400+1293.4)=2.38(V) ≒2.4(V)
Therefore, Pr.07.14 should be set to 2.4.
550
1330
temperature ( )
℃
resistor value ( ) Ω
Tr
Tr-5
℃ Tr+5 ℃