Omron E5AN User Manual page 113

Using Heater Burnout, Heater Short, and Heater Overcurrent Alarms
Three-phase Heaters
Burnout
Burnout
200 V
15 A
200 V
200 V
Product
To CT input
15 A
Product
To CT input
Current when there is a burnout = 10 A
Heater burnout detection current =
15 + 10
= = 12.5 [A]
2
Delta Connecting Lines
Example: Using Three 200-VAC, 2-kW Heaters
Normal
17.3 A
200 V
17.3 A
200 V
200 V
Product
To CT input
17.3 A
Product
To CT input
The current when each phase is normal is 17.3 A (
200 V
Load
CT
CT
3
( 3/2) = 15 A
The heater burnout current when there is a burnout at the load line is as fol-
lows:
(Heater burnout detection current) = (17.3 + 15) / 2
The heater burnout current when there is a burnout at the load is as follows:
(Heater burnout detection current) = (17.3 + 10) / 2
To enable detection in either case, use 16.1 A as the heater burnout detection
current.
(Normal current) + (Heater burnout current)
Load
CT
Burnout
10 A
200 V
17.3 A
200 V
Product
To CT input
10 A
Product
To CT input
Current when there is a burnout = 10 A
Section 3-10
2
3 10 A).
Burnout
Load
CT
CT
3
(1/ 3) = 10 A
16.1 [A]
13.65 [A]
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