Installing Current Transformers (Ct) - Omron E5CN User Manual

Using Heater Burnout, Heater Short, and Heater Overcurrent Alarms

3-10-2 Installing Current Transformers (CT)

Single-phase Heaters
Three-phase Heaters (E5AN-@@HH@-N, E5EN-@@HH@-N, and E53-CN@@HHN2 (for E5CN) 3-phase
Heater Detection Models)
1,2,3...
62
• If there is little difference between the current in normal and abnormal
states, detection may become unstable. To stabilize detection, set a cur-
rent value difference of at least 1.0 A for heaters of less than 10.0 A, and
at least 2.5 A for heaters of 10.0 A or more. If the heater current is too low,
loop the load line several times through a CT, as shown in the diagram
below. Looping it through once will double the detection current.
Load line
CT
• This function can be used with E5@N models that have the HB alarm, HS
alarm, and OC alarm.
For the E5CN, connect the CT in advance to terminals 14 and 15 (CT1),
or 13 and 15 (CT2). For the E5AN/EN, connect the CT in advance to ter-
minals 14 and 15 (CT1) or 15 and 16 (CT2). Then pass the heater power
line through the CT's hole.
For specifications, models and dimensions of current transformers that
can be used with this Controller, refer to Appendix Current Transformer
(CT) on page 256.
For single-phase heaters, install the CT in the position shown in the following
diagram.
AC line
CT
Product
To CT input
When a 3-phase power supply is used, regardless of the types of connecting
lines, two current transformers (CTs) are required to detect heater burnout,
HS, and OC.
1. Delta connecting lines: Refer to the following diagram for CT installation
positions.
Note Heater voltage fluctuations are not considered here, so be take that
into account when setting the detection current.
AC line
Product
To CT input
AC line
Product
To CT input
2. Star connecting lines: Refer to the following diagram for CT installation po-
sitions.
Note Heater voltage fluctuations are not considered here, so be take that
into account when setting the detection current.
Load (such as a heater)
Load
Load (such as a heater)
Load
CT
Section 3-10