TOHO ELECTRONICS TTM200 - Manual (Page 111)

48-7009-E 5-41
■ Calculation of the CT 1 abnormal current value setting
Detection current to be set is calculated with the following equation as an indication:
∴ CT 1 abnormal current value setting value = Current normal value + current at heater disconnection
2
Note Take care that the current in a multiplication factor of N flows when the load wire is wound
around CT N times due to too small a measurement current. Sixty amperes or 6 times the
actual current of 10 A flows when the load wire is wound around CT 6 times.
Example: Heater of 100 V, 2kW
[When normal]
[When disconnected]
Load
Load
To equipment
CT input
To equipment
CT input
Disconnected
The current on the heater is 20 A at normal and 0 A at disconnected, thus the CT 1 abnormal current value
setting value is as follows.
∴ CT 1 abnormal current value setting value =
Current normal value + current at
heater disconnection
2
20 + 0
2
= = 10 [A]
■ Example of parameter setting
The example shown below is identical to the above example, except where CT 1 is installed on the
output 1 and CT abnormality is provided as output on the output 2.
SEt6
oUt2
Name Setting content Setting value
o2F Target connection setting Event output 2
E2F3
Event function 3 setting (CT
abnormality) All modes, no added function, CT 1
abnormality
001
SEt12
CT
Name Setting content Setting value
CI1
CT 1 target connection setting Connected to OUT 1 (allowed to be
set in case of DO)
1
Ct1 CT 1 abnormal current value setting 10.0