48-7009-E 5-42
■ For 3-phase
■ Delta connection
Example: Where 3 heaters of 200 V and 2 kW are used
Normal current is 17.3 A (≒√3 × 10 A) for each phase.
[When disconnected in between phases]
[When disconnected on load side]
Current when disconnected = 10A√3(√3/2)
= 15A
Current when disconnected = 10A√3(1/√3)
= 10A
The heater disconnection detection current value when disconnection occurs in between phases is as
follows.
CT 1 abnormal current value setting value = (17.3 + 15)/2 ≒ 16.1 [A]
The heater disconnection detection current value when disconnection occurs on the load side is as follows.
CT 1 abnormal current value setting value = (17.3 + 10)/2 ≒ 13.65 [A]
For detection in both cases, the CT 1 abnormal current value setting value is to be 16.1 A.
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