95
Detecting Current Errors
Section 4-5
■
Examples
1.
Single-phase Heaters
Example 1 Using a 200-VAC, 1-kW Heater
The heater current is 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:
Example 2 Using Three 200-VAC, 1-kW Heaters
The heater current is 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:
∴
Heater burnout detection current
=
Normal current value + Burnout current value
2
Normal operation
Heater burnout occurred
CT
To CT input
AC line
Load
5 A
5 A
200 V
CT
To CT input
AC line
Load
0 A
200 V
Burnout
=
5 + 0
= 2.5 A
2
Normal operation
Heater burnout occurred
CT
To CT input
AC line
Load
15 A
200 V
Load
Load
15 A
CT
To CT input
AC line
Load
10 A
200 V
Load
Load
10 A
Burnout
∴
Heater burnout detection current
=
Normal current value + Burnout current value
2
=
15 + 10
= 12.5 A
2
Summary of Contents for EJ1 EtherCAT
Page 2: ...EJ1 Modular Temperature Controllers User s Manual Revised July 2008 ...
Page 3: ...iv ...
Page 19: ...xx ...
Page 213: ...188 Detailed Description of Services Section 6 4 ...
Page 227: ...202 Detailed Description of Services Section 7 5 ...
Page 303: ...278 Index ...
Page 305: ......