Installing Current Transformers (Ct) - Omron E5AN-H User Manual

Using Heater Burnout, Heater Short, and Heater Overcurrent Alarms

3-10-2 Installing Current Transformers (CT)

Single-phase Heaters
Three-phase Heaters
(E5@N-H@@HH@ 3-phase
Heater Detection Models)
72
• For Controllers with heater burnout, HS, and heater overcurrent alarms,
an OR output is established between the ALM 1 function and the alarms.
If the ALM1 function is to be used for the heater burnout, HS, and heater
overcurrent alarms only, set 0 as the alarm 1 type (i.e., do not use ALM1).
• Turn the heater power ON simultaneously or before turning ON the
E5@N-H power. If the heater power is turned ON after turning ON the
E5AN-H power, the HB alarm will be activated.
• Control is continued even when the heater burnout, HS, or heater over-
current alarm is active.
• The rated current value may sometimes differ slightly from the actual cur-
rent flowing to the heater.
Use the Heater Current 1 Value Monitor, Heater Current 2 Value Monitor,
Leakage Current 1 Monitor, and Leakage Current 2 Monitor parameters to
check the actual current being used.
• 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
• This function can be used with E5@N-H models that have the HB alarm,
HS alarm, and OC alarm.
For the E5CN-H, connect the CT in advance to terminals 14 and 15
(CT1), or 13 and 15 (CT2). For the E5AN-H/EN-H, connect the CT in
advance to terminals 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, see Appendix Current Transformer (CT)
on page 300.
For single-phase heaters, install the CT in the position shown in the following
diagram.
AC line
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.
■
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.
CT
Load (such as a heater)
Load
CT
Section 3-10