signal noise messing up my panel volt meter?
- Thread starter monster
- Start date
rkosiorek
100 kW
i'l bet that you are using one of those cheap LED or LCD panel meters. it would not be an issue with old moving coil meters.
could be one of two problems. most likely is that most of these meters need to be powered by an isolated supply. if you power them with the same voltage that you are trying to measure it will cause ground loops and erratic readings. easiest way to check would be to power the meter using a couple of batteries.
the instructions (destructions?) that came with the meter might also state if it needs an isolated supply.
rick
could be one of two problems. most likely is that most of these meters need to be powered by an isolated supply. if you power them with the same voltage that you are trying to measure it will cause ground loops and erratic readings. easiest way to check would be to power the meter using a couple of batteries.
the instructions (destructions?) that came with the meter might also state if it needs an isolated supply.
rick
Tiberius
10 kW
Are you trying to measure the motor voltage?
That is a complicated 3 phase waveform.
Nick
That is a complicated 3 phase waveform.
Nick
Tiberius
10 kW
Matthew, that will be easier than a bike motor, but it will still be a noisy waveform.
A multimeter will have some smoothing/filtering for doing AC measurements and probably leaves that in circuit when doing DC ones. A naked panel meter may not. If its a digital panel meter then it only takes a small jitter to make the display look crazy. As Rick says, an old style mechanical analogue one would do its own smoothing.
You could try a simple RC smoothing circuit, values won't be critical.
Nick
A multimeter will have some smoothing/filtering for doing AC measurements and probably leaves that in circuit when doing DC ones. A naked panel meter may not. If its a digital panel meter then it only takes a small jitter to make the display look crazy. As Rick says, an old style mechanical analogue one would do its own smoothing.
You could try a simple RC smoothing circuit, values won't be critical.
Nick
