Union Jubilee Clutch.

[camallison]

Hi,

Thanks David for your compliment. Yes it's very strange that Huanyang make these excellent VFD's but then in the manual state a 10K Linear pot must be used; I did try a 5K pot making not a bit of difference. I'm a novice though with these VFD's and I feel as I gain more experience I could possibly locate the correct parameter to adjust allowing the pot to give full sweep but it all takes so much time. The VFD is remarkable value for money though and I'm delighted with mine so far.

Great idea Refugee. A few years ago my new cheap vac packed up and it would have cost more in postage to return it than throw the vac away. Out of curiosity I stripped the vac to find the speed control slider pot had expired due to ingress of dirt; I did as you suggest here and removed the slider pot replacing it with a fixed resistor giving fixed speed and the vac has been perfect ever since. I'm very wary though regarding playing around with the VFD adding remote controls; it took a lot of web browsing but eventually I installed the remote controls I needed and now only the pot could do with some fine tuning; I'm sure as David suggests a multi-turn pot would allow very fine speed adjustment but I really want to control the speed with a single turn of the pot. I've already bought the plastic gears and can experiment a bit once they arrive; I can turn this into a small project as I'll find it interesting.

I could easily do as you suggest Refugee and measure the actual pot resistance between off and full speed and I'm sure this would normally work by replacing the 10K pot with one of the new rating but I don't know what effect this would have upon the VFD control circuit; I feel the 10K pot is there for a reason; I did take a deep breath and try a 5K pot but without success so it's possible just a parameter requires adjusting and knowing how many hours I put in sorting the remote controls out I decided to experiment with reduction gearing which I understand removing the risk of damage? I do however very much appreciate your help and suggestions because I like to learn from people such as you are much more knowledgeable on things electronic.

Thanks Gary; I've had a quick look at the Blor Edwards website and what a selection of pots they have to the point of making bespoke pots; if you recall Gary I did some experimenting a few years ago making my own pots but for the more difficult AVO VCM saw-tooth pot I couldn't find a supplier of small quantities of resistance wire? I was successful though in making a bespoke pot for a petrol tank unit for a vintage car.

I'm just so busy converting the garage into a workshop to spend too much time concentrating on the pot problem because the Graduate is working extremely well indeed; it's just me nit picking wanting it to be perfect after all the TLC I've just expended on its rebuild over the last three weeks.

I'll have a look at the Blor Edwards website in more detail a bit later but in the meantime any ideas where I can buy a single turn heavy duty 10K Linear pot; the one I'm using is cheap and makes me wonder how long it will last before it expires?

Kind regards, Col.

Not sure if its in your price range, but:

http://www.ebay.co.uk/itm/7286R10KL-25-B...0940863354

Colin

[Joe]

Rapid have got some at silly money but also have some 4W wire-wound ones for about three quid, plus postage: http://www.rapidonline.com/Electronic-Co...ers-519692

As do Spiratronics: http://spiratronics.com/resistors-and-po...er-4w.html

- Joe

[Eddystonepete]

Hi Col, regarding your speed control pot, are you sure you wired it up correctly? It looks like one end of the track is earthed, the other going to + 10v. You should get this 10 volts across the 2 outside tags of the pot at any setting of the pot. You should also get a smoothly varying 0 to 10v between the middle tag and earth as the pot is turned. Hope I,m not telling granny to suck eggs etc. I use an ABB vfd on my ML7. It took me 2 days to understand the program!. Peter

[Retired]

Hi,

Many thanks once again Refugee. I actually tried coupling two 5K pots in series using just one of the wipers but however I tried I still could only obtain a limited sweep of the pot; it's strange but I know others have also had the same problem but not posted a solution and as I say Huanyang didn't reply to my email either.

Thanks Colin; money isn't a problem but I wanted a single 10K turn pot to save a lot of knob twiddling whilst woodturning.

Nice one Joe; thanks; I've just opened an account with Rapid and bought two of their 10K 4W wire wound pots for a total of just over £10 delivered next day. Whilst I'm at it I thought why not buy a spare and leave the spare ready in the enclosure. VAT & P&P sure bump up the cost of buying but hopefully once these arrive and I sort out a reduction drive I can settle down to using the lathe?

Perhaps I should have bought an ABB VFD Peter then I could have easily copied you but on this Huanyang VFD I tried swapping both end connections without success; oh dear; you've just prompted me to think about the wiper; don't say I've got the wiper connected wrongly and if so I'm not on my own? You could well have solved the problem Peter but I'll only know by a bit of re-connecting which I'll do tomorrow because its a black hole once again here. I hope it is that simple and if so once the wire wound pot is installed I should have years of trouble free running?

Update. I've now tried every way of wiring the pot using the three connections and the problem remains; I've had the pot working the opposite way around and hardly working at all so in conclusion it appears to have been correctly wired in the first place which I thought it to be but many thanks Peter it was well worth a try and a pity the solution wasn't as simple as a wrong connection? I didn't take voltage readings but considering I've tried every way of connecting I don't expect to find anything amiss but tomorrow is another day; if only the manufacturers would print circuits and instructions in a simple manner so that novices would at least have a chance of understanding basic connections but I can dream?

Kind regards, Col.

[Retired]

Hi,

What a morning's fun I've just had rolling around uncomfortably under the hall floor in order to access the VFD.

I've checked and double checked the pot to VFD connections and they are definitely correct. I get a reading as you say Peter of 0V-10V between track ends and rotating the wiper also does as you say giving a smooth reading between both ends.

The wiper is connected to V1 the ends of the track to VR (+10V) & ACM.

I find the diagram below most confusing and I've spent a while reading the instruction manual but still don't grasp what the diagram is trying to tell me. If I read it correctly V1 is voltage controlled whereas A1 is current controlled?; what are the rectangle and circle on the diagram depicting?

Its interesting though that I've now got voltage readings between off and full speed as follows wiper to track ends; 9.93VDC Stop and 8.31VDC Full speed.

Between stop and full speed the pot gives speed control but only within this narrow voltage band?

I've used the same DMM for over twelve years so as soon as I started this morning it decided to wind the key up in my back by not giving voltage readings in fact with the lathe running at full speed the pot read dead on the DMM. Eventually after playing around the DMM did finally give a voltage reading so then I hooked the DMM up using quick hook up leads only for the DMM to die again so a trip up to the workshop was called for to collect my brand new DMM. The more this job plays up the more frustrated I'm becoming and I'm digging in because I'll not give in without a fight. So near and yet so far.

The new plastic gears have arrived this morning and look useful.

Kind regards, Col.


           

[Nick]

I've just read the manual.

The A1 input is if you want to current control the device, which you are not doing (i.e. leave it n/c) - you are using voltage control via the 10K pot. Frankly, a 5K pot would be fine - its only acting as a potential divider giving 0-10V on the wiper.

Note that this pot should be LINEAR - it sounds like you may be using a LOG pot instead. - I'd get a DVM (NOT an AVO) and measure the voltage on the wiper as you rotate the pot - the measured voltage should be directly proportional to the angle of rotation, e.g. half rotated should be 5V, three-quarters should be 7.5V etc.

The dotted ovoid round the connections is indicating that you should be using a screened multi-core cable to connect the pot, with the screen earthed at the VFD end only. These sorts of inputs are very noise-sensitive - the screening will be important, especially if the wire to the pot is more that a meter or so. If the pot is on a plastic panel or an un-grounded panel, it may help to tack the screen to the pot case. Be careful you aren't creating a ground loop if you do this...

Is this a new or second-hand unit? If used, it may be that some of the system's parameter settings are no longer at their default values. What model do you have, and is it new? A factory settings reset can be done by setting PD013 to "8".

Cheers

[Refugee]

The voltage readings we now have are telling me that there needs to be a 2.2k pot from 10V to an 8k2 resistor with the other end connected to ACM.
That should open the range out to the full length of the pot track.

[Nick]

The voltage readings we now have are telling me that there needs to be a 2.2k pot from 10V to an 8k2 resistor with the other end connected to ACM.
That should open the range out to the full length of the pot track.

This is absolutely not the right way to sort this - the system's parameters should be used and a 10K or 5K linear pot connected between VR and ACM with the wiper connected to V1, all by a screened cable as specified section 4, item 2).

Firstly, can you read the values of parameters PD02 & PD070 ?

To use the external 0-10V control, PD02 should be set to "1" (the factory default is "0") and PD070 to "0" (which is the factory default and means use V1 with a range of 0-10V).

[pwdrive]

Refugees suggestion sounds the cheapest, either that or a helipot for a more broad control over the min to max speed as has been previously suggested.

Lawrence. [EDIT: Whoops, just missed nicks post, yes parameters check, if no go then try refugees idea]

[Refugee]

A scan of the parts of the manual covering the connections and what they do will help us a lot.
I did say a long way back that there aught to be a setting for the control voltage range.
If it can be found then a 10k pot should work.
It looks like the pot may be driven by a constant currant that can be adjusted from the diagram.
A1 and ACM are the pins we need to read about.