K8AC-CT20S Omron, K8AC-CT20S Datasheet - Page 10

• Manufacturer Part Number: K8AC-CT20S
• Description: CURRENT TRANSFORMER .2-22A
• Manufacturer: Omron
• Series: K8ACr

Specifications of K8AC-CT20S

• Accessory Type: Current Transformer
• For Use With/related Products: *
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: K8ACCT20S

10
K8AC-H
Heater Connection Methods and Current
Depending on the heater connection method, the current when an error occurs will be as shown in the following table. Refer to this table when
determining burnout alarm set values.
Note: This is the current for when a 200-V, 1-kW heater is used for single-phase or three-phase operation.
Rate of Change for Currents with Parallel Heaters
The following table shows the current change ratios when multiple heaters of the same capacity are connected in parallel and one of the heater
elements burns out. Use this table for reference when making corrections.
If five single-phase heaters are connected in parallel, the current change when burnout occurs is 20% per heater.
For example, if the current for a single heater is low and the change ratio is very slight, it may not be detected. Therefore take into account the
detection accuracy for the total current when selecting the number of heaters to be connected in parallel.
Note: 1. The figures in the above table show the current change ratios when burnout occurs for one heater connected in parallel.
Single-phase
Three-
phase
Single-
phase
Star
connection
Delta
connection
2. The numbers represent the current ratio after one heater burns out, with the current prior to the burnout (i.e., the normal current) taken
3. In actual operation there may be effects from factors such as load (heater) imbalances, so conduct an actual test for confirmation before
4. Consult with your OMRON representative if multiple heaters are used with different heater capacities.
as 1.
making adjustments if the current change ratio between normal and abnormal operation is slight.
Delta
connection
Star
connection
V
connection
Number of heaters
per phase = n
I
I
I
Connection
n heaters
Number of
heaters per
phase = n
200 V
200 V
200 V
200 V
200 V
200 V
200 V
200 V
200 V
200 V
Normal condition
(5 A × 3 = 8.7 A)
Current in burned-
out phase
Current in other
phases
Current in lines
near burned-out
phase (Same as 2-
phase.)
Current in other
phases
5 A
(5 A × 3 )
(5 A ×
8.7 A
8.7 A
8.7 A
2.9 A
2.9 A
2.9 A
8.7 A
5 A
5 A
1
3
1 kW
)
1 kW
5 A
1 kW
1 kW
1 kW
1kW
1 kW
1 kW
1 kW
With one heater
With one heater
burned out,
burned out,
I is 0.
I is 0.
0.87
0.58
n=1
1
(5 A ×
(5 A × 3 ×
(5 A ×
7.5 A
7.5 A
2.5 A
2.5 A
2.5 A
2.5 A
1
3
1
2
0.92
0.77
n=2
×
)
0.5
0.6
1
3
2
3
2
)
)
200 V
Abnormal condition
0.67
0.75
0.95
0.84
n=3
0 A
1
0 A
(5 A × 3 ×
(5 A ×
(5 A × 1)
8.7 A
5 A
5 A
2.5 A
2.5 A
5 A
5 A
0.75
0.82
0.96
0.88
n=4
1
1
3
×
1
3
3
2
)
)
0.86
0.97
0.91
n=5
0.8
1