Cling free

[ptonsparky]

One of my customers has a problem with the needles on their amp meters for large motors. Just touching the instrument face causes the needle to jump around and it does not seem to give them a stable reading.

I am thinking wiping the instrument face with one of the wifes anti static dryer sheets might do the job.

Anyone have a similar problem and/or solution?

 

[whillis]

I assume that the amp meters are not in series with the motor but are connected to the secondaries of current transformers. If one of the wires connecting the CT to the meter has a break you can get a large voltage rise on the CT secondary that can cause the needle to jump when anything conductive is placed near the face.