Installing Current Transformers (Ct) - Omron E5C User Manual

• Setting the Leakage Current Value Monitor
1
Press the M Key several times in the Adjustment Level to dis-
play lcr1 (Leakage Current 1 Value Monitor).
2
Check the leakage current from the CT input that is used to
detect heater short.
The monitoring range is 0.0 to 55.0 A.
• Setting Heater Short Alarm Detection
1
Press the M Key several times in the Adjustment Level to dis-
play hs1 (HS Alarm 1).
2
Press the U or D Key to set the set value to 2.5
Refer to 4-12-4 Calculating Detection Current Values when you set
the value.
• If there is little difference between the current in normal and abnormal states, detection may be
unstable. To stabilize detection, set a current difference of at least 1.0 A for heaters lower than
10.0 A, and at least 2.5 A for heaters of 10.0 A or higher. If the heater current is too low, loop the
load line several times through a CT, as shown in the following diagram. Looping it through once
will double the detected current.
Load line

4-12-3 Installing Current Transformers (CT)

• CTs can be used for the heater burnout (HB) and heater short (HS) alarms.
For the E5CC, connect the CT in advance to terminals 16 and 17 (CT1), or 17 and 18 (CT2). For the
E5EC/E5AC, connect the CT in advance to terminals 19 and 20 (CT1) or 20 and 21 (CT2). For the
E5DC, connect the CT in advance to terminals 7 and 8 (CT1). Then pass the heater power line
through the hole in the CT. For specifications, models, and dimensions of the CTs that can be used
with the Digital Controller, refer to A-2 Current Transformer (CT).
(1) Single-phase Heaters
For single-phase heaters, install the CT in the position shown in the following diagram.
AC line
Product
To CT input
(2) Three-phase Heaters
When a 3-phase power supply is used, regardless of the types of connecting lines, two
current transformers (CTs) are required to detect heater burnouts and heater shorts.
E5@C Digital Temperature Controllers User's Manual (H174)
Set value of HS Alarm 1/2 parameter = (Leakage current value
when output is OFF + Current value during heater short-circuit
× Number of loops)/2
CT
Load
Load (such as a heater)
CT
4 Basic Operation
Adjustment Level
lcr1
Leakage Current 1
Value Monitor
0.0
lcr1
1.0
Adjustment Level
hs1
HS Alarm 1
50.0
hs1
2.5
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