Drip Drop PC-200 - 5.2.6 Current inputs

MANUAL PC-200
Ver. 2.12.xx/10/22/2010-UK
Page 23 (61)
5.2.6 Current inputs
The unit measures the current consumption for each pump P1, P2, P3 in one phase by the use of a
X/5 Amp current transformer. As for the voltage inputs this function has to be activated and a
transformation factor (rate) has to be given.
Normally the smallest ring transformers are rated 50/5 amps.
If a smaller than 50 amps. pump is measured, you will need to wind the phase power cable around the
transformer coil in order to increase accuracy, the as shown in the illustration below. Each turn of the
coil will lessen the rated current in to the transformer. See the following figure.
Once the correct number of turns around the coil is applied, you need to calculate the total
transformation factor.
You need to consider the transformer rate as well as the transformation rate for the winding around the
coil. You calculate the transformation factor the following way:
Figure 5.2.6 shows how one of the phases of the phases of the
pump is fed around the transformer coil.
For a 50/5 A transformer the following reduction in the measured input
current applies:
1 turn will give a 25/5 amps. rate. (for a pump up to 25 Amps.)
2 turns will give a 12,5/5 amps. rate. (for a pump up to 12,5 amps.)
3 turns will give a 6,25/5 amps. rate.(for a pump up to 6,25 amps.)
Example 1.
Using a 50/5 A transformer to measure a 35 Amps pump.
The transformer ratio is 10 .
Set the transformation factor in the PC 200 to 10.
Example 2.
Using a 100/5 A transformer to measure a 75 Amps pump.
The transformer ratio is 20 .
Set the transformation factor in the PC 200 to 20.