ABB REB650 Technical Manual page 134

Section 8
Voltage protection
128
VA or VAB
Comparator
V < Pickup1
VB or VBC
Comparator
V < Pickup1
VC or VCA
Comparator
V < Pickup1
MinVoltSelector
Comparator
V < Pickup2
Comparator
V < Pickup2
Comparator
V < Pickup2
ANSI08000016 V2 EN
Figure 51: Schematic design of Two step undervoltage protection UV2PTUV (27)
Phase A
Voltage Phase
Selector
OpMode1
Phase B
1 out of 3
2 out of 3
Pickup
Phase C
3 out of 3
&
Trip
Output
Logic
PICKUP
Step 1
Time integrator
TRIP
t1
Phase A
Voltage Phase
Selector
OpMode2
Phase B
1 out of 3
2 out of 3
Pickup
Phase C
3 out of 3
&
Trip
Output
Logic
PICKUP
Step 2
Timer
TRIP
t2
1MRK 505 277-UUS C
PU_ST1_A
PU_ST1_B
PU_ST1_C
OR
OR
OR
OR
PICKUP
OR
TRIP
OR
ANSI08000016-2-en.vsd
Technical Manual