Union Jubilee Clutch.

[Retired]

Hi,

Many thanks Refugee; Peter; Joe and Nick for wading in with so much information; I'm obviously having a lot of difficulty with just this pot issue and I know others too are also having the same difficulty so it's great to get all this information in one place. I could of course battle on in silence until I find the solution but I'm happy to share my difficulty in the hope it helps others and it's certainly doing as intended in generating interest on the forum.

Thanks also for the assorted downloads and the one of Joe's at 10.7M is the manual supplied with the VFD. I'd like to make it clear that I'm not in any way calling this VFD because I think it a wonderful bit of kit especially at the price I paid for it; the problem is my lack of understanding/experience but I'm learning a lot from your replies. These VFD's are complicated and it takes a determined novice to get one to work successfully so I'm pleased so far because the Graduate is running beautifully through my VFD with only the pot to sort out to make it perfect; the lathe is fully usable but I want the pot to work on full sweep and I know a 10K pot can be made to work otherwise Huanyang would not have suggested it?

When I first received the VFD and wired it up to the motor sitting on the bench I was totally new to such devices and at first power up I thought the motor would never stop accelerating; I think it topped out at over 10,000 rpm and was running absolutely smoothly which highly impressed me. I had missed changing one of the frequency parameters so the motor was running on 400HZ?

The motor is a top quality Brook Motor; inverter rated at 60HZ I think it's a 1690rpm and connected at 220V. Motors don't come any better because I worked at Brooks for 24 years.

The VFD was bought brand new.

I set the VFD parameters from the motor nameplate; I adjusted the parameter to work from remote control PD002 at "1" for remote control.

I note the top speed is around 2250rpm which I want to increase to 3000rpm but I think I need to go back into manual mode to adjust this because I'm unable to adjust whilst the remote controls are set active but this is a small point and something I'm sure I can sort out.

Your suggestion Refugee of using a pot and series resistor is actually something I can easily follow and understand. I have actually tried using a single 5K pot without success and yes the pots I'm using are Linear.

Whilst testing with the DMM this morning the pot was working perfectly giving the 0V- 10V throughout its full sweep but it was the VFD which wasn't responding correctly through V1? The +10V and the ground being fixed at each end of the track only really leaves the wiper (V1) variable.

I take your point about screening being important Nick but would poor screening actually allow the pot to give perfect control of the speed through such a small sweep without some kind of adverse reaction from the VFD? I know nothing of such things and as you've raised this valid point once the new pots arrive I'll connect one directly to the VFD with a very short cable to eliminate this from the equation; if it works of course I'll soon buy a screened cable and install it.

For what its worth my humble opinion is that the fault lays in the parameters and perhaps just one parameter needs adjustment but which one? I don't have a full circuit diagram so am unsure what V1 is actually connected to internally?

Whilst running both the VFD and lathe show absolutely no signs of distress in fact when I'm at the VFD I can't even hear the lathe running because the lathe is so quiet; I only know it to be running by the rpm readout on the VFD because the lathe and VFD are separated by a solid brick wall.

We've had a visitor this afternoon so I'll be back on this job tomorrow.

Thanks once again everyone; its nice to receive so many replies and such interest.

Kind regards, Col.