53
creases. The displayed heater current value increases in proportion to the
number of turns of the wire passing through the CT.
Heater wire
The wire passes
through the CT
twice.
3. Obtain the heater burnout alarm value using the method in example 1.
Apparent normal current = (400 + 1700 + 2000)
200 x 2 = 41.0 A
Normal heater
current value
Apparent heater burnout current = (41.0 – 400
200) x 2 = 37.0 A
Heater burnout
current value
Normal current – heater burnout current = 41.0 – 37.0 = 4.0 A (
2.5 A)
Heater burnout alarm value = (41.0 + 37.0)
2 = 39.0 A
Heater burnout
alarm setting
Heater Burnout Alarm Value
Section 8-4
