MI 2792 PowerQ4 Plus
Recording Practice and Instrument Connection
93
Measuring setup:
Current transformer:
Prim: 600
Sec: 5
Current clamps:
A1122 (5A/1V)
100 A
Measuring Setup:
I Range: 100%
100A load feeding
Load
PowerQ4 display:
Irms = 100 A
Current Transformer:
600A : 5A
Figure 4.12: Current clamps selection for indirect current measurement
Over-dimensioned current transformer
Installed current transformers on the field are usually over-dimensioned for “possibility
to add new loads in future”. In that case current in primary transformer can be less than
10% of rated transformer current. For such cases it is recommended to select 10%
current range as shown on figure bellow.
Figure 4.13: Selecting 10% of current clamps range
Note that if we want to perform direct current measure with 5 A clamps, primary
transformer ratio should be set to 5 A : 5 A.
WARNING !
The secondary winding of a current transformer must not be open when it is on a live
circuit.
An open secondary circuit can result in dangerously high voltage across the terminals.
