Application Examples - Omron E5AN User Manual

Using Heater Burnout, Heater Short, and Heater Overcurrent Alarms

3-10-4 Application Examples

Single-phase Heaters
Normal
5 A
200 V
5 A
Product
To CT input
Normal
15 A
200 V
15 A
Product
To CT input
76
• Make sure that the following conditions are satisfied:
Heater with a current of less than 10.0 A:
(Current value at normal operation)
1 A
When the difference is less than 1 A, detection is unstable.
Heater with a current of 10.0 A or more:
(Current value at normal operation)
2.5 A
When the difference is less than 2.5 A, detection is unstable.
• The setting range is 0.1 to 49.9 A. Heater burnout, HS, and heater over-
current are not detected when the set value is 0.0 or 50.0. When the set
value is 0.0, the heater burnout alarm is always OFF, the HS alarm is
always ON, and the heater overcurrent alarm is always ON. When the set
value is 50.0, the heater burnout alarm is always ON, the HS alarm is
always OFF, and the heater overcurrent alarm is always OFF.
• Set the total current value for normal heater operation to 50 A or less.
When a current value of 55.0 A is exceeded, ffff is displayed in the
Heater Current 1 (or 2) Value Monitor and Leakage Current 1 (or 2) Moni-
tor parameters.
Example: Using a 200-VAC, 1-kW Heater
AC line
Load
CT
The heater power supply provides 5 A when the current is normal, and 0 A
when there is a burnout, so the heater burnout detection current is calculated
as follows:
Heater burnout detection current =
5 + 0
= = 2.5 [A]
2
Example: Using Three 200-VAC, 1-kW Heaters
Load Load Load
CT
The heater power supply provides 15 A when the current is normal, and 10 A
when there is a burnout, so the heater burnout detection current is calculated
as follows:
(Current value at heater burnout)
(Current value at heater burnout)
Burnout
AC line
200 V
Burnout
0 A
CT
Product
To CT input
(Normal current) + (Heater burnout current)
Burnout
10 A
200 V
10 A
Product
To CT input
Section 3-10
Load
Load (such as a heater)
2
Load Load Load
Burn-
out
CT