The Tacho/RPM meter for the lathe is still fighting me. :(
I put ferrit supressors on power in/out and 3-phase out. I expect to be hearing from the RSPCA later as ferrit suppression may be an offence.

I tried a test of the tachometer with just the RPM box of tricks and the VFD powered on but not "started" (i.e. delivering any 3-phase output). This was using a cordless drill and a magnet as suggested by @Bobsticle of this parish and as expected all works fine steady numbers and responds to varying speeds of the drill; solid as a rock. :D

However, start the VFD delivering actual output and everything goes belly up. :(

So it is pure and simple the level of EMI/RFI escaping the VFD that screws everything up.
I wonder if putting it in a grounded biscuit-tin would help? ;)
 
I am doing a little "Happy Dance" :dance: because the lathe rev-counter is working 100%.
The item bought from Amazon came in a box with "Zero/Zilch/Denada" info as to "how".
I've been struggling all day with ferrite noise suppressors etc. etc. all to no avail. :-(
Then I did a google search online and up popped an e-bay link to a similar product to mine (AC powered) but it offered 2 variants. Unshielded sensor, or "Shielded Sensor". Now I just added a shield to my sensor yesterday and it made NO difference. But, when reading this e-bay seller ad it became clear that for usage where there is possibly RFI/EMI from a VFD you should buy their shielded version and attach the sensor shield NOT TO EARTH but to the -ve terminal of the sensor connection to the tacho.

Boom! and I am a very happy man. :mexicanwave:

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Managed to drop a, thankfully not too big, piece of worktop on me foot. :(
As I pointed out to W if I'd been wearing my steelies it'd have made no diff as it fell on the part of my foot about 3 inches above where the toecap ends. I didn't exactly drop it, I'd attached it to the sink with two of the sink mounting clip type things as I was messing about trying to get the cabinet below where it will be going to as near as I can the right height so I don't have to recut holes in the back board for the water pipes and drain. Somehow it came detached as I was turning the sink over and around.
Had to reposition the clips as the noo top is thicker, by a bit. That was a battle having to push the wretched tongue thing in while fiddling the rest of the clip mounting around to get it to slip up (or down if the sink was the right way up!) to the next hole in the vertical metal edge.
Progress on this thing is very slow as I procrastinate like mad cos i have got sooo bored with the job.
I keep trying to tell myself, "Get on and get the flipping thing done." But I don't listen. Spend too long on tinternet and nattering to you lot!!!
Have a good evening!:):):)
 

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