TOHO ELECTRONICS TTM200 - Manual (Page 113)

48-7009-E 5-43
■ Star connection
Example: Where 3 heaters of 200 V and 2 kW are used
[When normal]
To equipment
CT input
To equipment
CT input
Load
Load Load
Normal current is 5.8 A {≒10 A × (1/√3)} for each phase.
[When disconnected in between phases]
To equipment
CT input
To equipment
CT input
Load
Load Load
Disconnected
Current when disconnected in between phases = 10 A Ч (1/√3) Ч (√3/2) = 5A
[When disconnected on load side]
To equipment
CT input
To equipment
CT input
Load
Load Load
Disconnected
Current when disconnection occurs on the load side = 10 A Ч (1/√3) Ч (√3/2) = 5A
The CT 1 abnormal current value setting value for this connection is 5.4 A {= (5.8 + 5)/2}.