Omron G3ZA - MANUAL 2 User Manual page 59

Detecting Heater Burnouts (4-channel Models Only)
Burnout current = 30 A ×
200 V
Burnout current = 10 A ×
42
1
×
2
3
= 15 A
The following formula yields the heater burnout current for the main wiring.
Heater burnout detection value =
c. V Wiring
Example: Using two 2-kW heaters (200 V AC)
Normal Operation:
10 A
200 V
To CT input
200 V
17.3 A
200 V
10 A
To CT input
Burnout Occurred:
5 A
CT
200 V
To CT
input
Load such
Wire
as a heater
200 V
break
CT
5 A
To CT
input
1
2
= 5 A
The following formula yields the heater burnout current when there is a break
in the common wire.
Heater burnout detection value =
The following formula yields the heater burnout current when there is a break
in the load wire.
Heater burnout detection value =
To detect a wire break at either location, set a heater burnout detection value
of 7 A.
3
Burnout current = 30 A ×
17.3 + 15
2
CT
Load such
as a heater
CT
10 A
200 V
200 V
10 A
200 V
Burnout current = 0 A
10 + 5
2
10 + 0
2
Section 4-5
3
1
×
2
3
= 15 A
= 16.15 → 16 [A]
CT
To CT
input
Load such
as a heater
CT
Wire
To CT
break
input
= 7.5 → 7 [A]
= 5 [A]