Measuring noisy voltage

[coshkun]

We had some interference problems when we measure a motor supply voltage and some other voltages.We want to isolate motor voltage.What can we use to measure this voltage with isolation?

 

[vaibhav.k]

U have to use isolation signal transformer with capacitor at CRO tip

 

[barry14]

You should measure the voltage differentially so interference on both leads will cancel. There are special differential amplifiers available from the major oscilloscope manufacturers. A simpler approach is to use a 2-channel scope set up to display the difference between the channels. You need to adjust the gain of one channel to match the other to obtain best rejection of common mode signals. This can be done by connecting both channels to the same signal and adjusting the gain of one channel to minimize the display.

 

[ho83]

if the problem is the islation, then try to use an optocoupler

 

[ameed]

hi all,

There are special differential amplifiers available from the major oscilloscope manufacturers.

approach is to use a 2-channel scope set up to display the difference between the channels.

You need to adjust the gain of one channel to match the other to obtain best rejection of common

mode signals. This can be done by connecting both channels to the same signal and adjusting

the gain of one channel to minimize the display.

thanx.