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PM
-
3033 User’s Manual v1.20
Last Revised:Mar. 2017 Page: 68
Copyright © ICP DAS Co., Ltd. All Rights Reserved.
E-mail: [email protected]
Q7. How to measure the Voltage large than 500V?
For service voltage above 600 Vac, voltage transformers (PTs) are used to step down the
voltage to a lower range that will work with a PM-3033 meter.
Selecting a Transformer:
Selecting the right voltage transformer is simple. Review the following
considerations to determine the best fit for your application.
Input Voltage:
Select a transformer that will operate on the supply voltage available at your facility
(Example: PRI. Voltage 720V; SEC. Voltage 120V). Check the connection diagram
(three-phase Y and delta; phase sequence) to ensure compatibility.
Adding potential transformers has the effect of reducing the measured line voltage by the PT
ratio (let's say 6:1 for this example). So a voltage of 720 Vac becomes 120 Vac. Since the
meter sees 120 Vac, many of the measurements it reports will be low by a factor of 6 unless
they are scaled up by 6.
Frequency:
If you are operating in the United States, you will most likely be operating on 60 Hz. However
should you need a 50 Hz rated transformer.
Accuracy: Transformer (PT) accuracy (Example: 1% or 3%) will influence the measurement.
Rated Output (VA): Example: 150 VA (50VA per phase).
Q8. How to use 5A output CT's with PM-3033 Power Meter?
The CT inputs of the PM-3033 can handle a maximum of 5A current.
PM-3033's current ratio is always full scale to 5A.
Adding current transformer (5A Output CTs) has the effect of reducing the measured current
by the CT ratio (let's say 40:1 for 200A CT as example). So a current of 200A becomes 5A.
Since the meter sees 5A, many of the measurements it reports will be low by a factor of 40
unless they are scaled up by 40.
Current
transformer
CT Ratio
(PM-3033)
Current
transformer
CT Ratio
(PM-3033)
50A CT
10:1
400A CT
80:1
100A CT
20:1
800A CT
160:1
200A CT
40:1
1000A CT
200:1