Low frequency Voltage measurement

[neevedit]

Hi,

I am using PCI 6025E to control load bank and to measure voltage, current and frequency of a generator.
While current and frequency measurement  is not a problem, voltage measurement is toublesome.
Since on test bench already there are few PCI boards and huge number of sensors, I do not want to add NI 9205 or any other additional boards and clutter the area (other people are also working there).

The problem with voltage measurement is that out of three generators two run from 400 RPM to 1600 RPM i.e.. somewhat 15-55 Hz.

I had two solutions for this:

1, Putting a step down transformer (230 Vac / 5 Vac) and then measure the voltage. But when testing at somthing like 15 Hz I have to deal with magnetic saturation with commercially available transformer. I do not want to take pain to go on built my own transformer.

2, Using high precision voltage Divider. The problem is that what should be the galvanic isolation? Isolation transformer, but then again low frequency problem.

Hence could someone suggest me since there is a bit confusion in my head.

Thanks.

[Henrik_Volkers · Accepted solution]

If you have a sine generator (15Hz migth be hard for the soundcard 😉 ) you can do a calibration of your transformer.

(If only the voltage amplitude is of interest , use a isolated DMM as reference and run your generators)

Or you buy a isolation voltage sense amplifier. (weidmueller, phoenix, wago, ...)

[neevedit]

Thanks for the reply, Henrick

I think DMM will work.