Hi all,
I'm after suggestions for a quick project. I have a dirty water pump that runs on a 3 phase. I've had problems with rats nibbling the wires, and various other things interfering with the supply. There's earth leakage sensing etc on the vfd that drives it but it won't pick up if the feed to one phase is broken. This leads to to much current going through the other two phases and burning one out.
The simplest way of checking it I can think of is to wrap a few turns of copper wire around each wire going to the motor then using a diode and capacitor as a peak detector. This could be then be checked by the adc on a pic, if a wire gets broken there would be no current through it, therefore to voltage across my mini coil. I can the get the pic to stop the vfd and avoid damaging my pump motor again?
Is my idea practical/workable, does anyone else have a better one?
Cheers Geoff
I'm after suggestions for a quick project. I have a dirty water pump that runs on a 3 phase. I've had problems with rats nibbling the wires, and various other things interfering with the supply. There's earth leakage sensing etc on the vfd that drives it but it won't pick up if the feed to one phase is broken. This leads to to much current going through the other two phases and burning one out.
The simplest way of checking it I can think of is to wrap a few turns of copper wire around each wire going to the motor then using a diode and capacitor as a peak detector. This could be then be checked by the adc on a pic, if a wire gets broken there would be no current through it, therefore to voltage across my mini coil. I can the get the pic to stop the vfd and avoid damaging my pump motor again?
Is my idea practical/workable, does anyone else have a better one?
Cheers Geoff