Omron E5CN User Manual page 91

Using Heater Burnout, Heater Short, and Heater Overcurrent Alarms
Burnout
Burnout
Load (such as a heater)
200 V
200 V
5 A→
200 V
Product
To CT input
5 A→
Product
To CT input
Current when there is a burnout = 10 A × (1/√3)
66
Star Connecting Lines
Example: Using Three 200-VAC, 2-kW Heaters
Normal
5.8 A→
200 V
200 V
5.8 A→
200 V
Product
To CT input
5.8 A→
The current when each phase is normal is 5.8 A ( ≈ 10 A × (1 / √ 3)).
CT
CT
× (√3/2) = 5 A
The heater burnout detection current for this connecting line is 5.4 A (= (5.8 +
5) / 2).
Load (such as a heater)
CT
CT
Product
To CT input
5 A→
Load (such as a heater)
200 V
200 V
5 A→
200 V
Product
To CT input
Product
To CT input
Current when there is a burnout = 10 A × (1/√3)
Section 3-10
CT
Burnout
CT
× (√3/2) = 5 A