Delta Electronics AC Motor Drive VFD-EL User Manual page 118

resistor-divider
Refer to following calculation for protection level and warning level.
1. Protection level
Pr.07.14= V
2. Warning level
Pr.07.16= V
3. Definition:
V+10: voltage between +10V-ACM, Range 10.4~11.2VDC
R : motor PTC overheat protection level. Corresponding voltage level set in Pr.07.14,
PTC1
R : motor PTC overheat warning level. Corresponding voltage level set in Pr.07.15,
PTC2
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.
Revision August 2008, 2ELE, V1.02
R1
PTC
* (R //47K) / [R1+( R
+10 PTC1
* (R //47K) / [R1+( R
+10 PTC2
Chapter 4 Parameters|
VFD-EL
+10V
AVI
47kΩ
ACM
internal circuit
//47K)]
PTC1
//47K)]
PTC2
4-75