Here is a list of all the postings An Other has made in our forums. Click on a thread name to jump to the thread.
|Thread: A beginners locomotive|
Sorry to put this here, folks - Del - can you contact me re drawings? - your inbox is full.
|Thread: Minilathe/Mill motors|
Thanks for the inputs - given me something to think about - just a few comments:
I have seen the operating voltage of these motors mentioned in many places, and frankly they seem totally contradictory - some sources say as low as 80VDC, others 120VDC, and yet others up to the 180VDC mentioned here by Pat, who also notes the boards are different. This may be the case, but as I said in my first post, the power supply for the motors is the same.
I know they use PWM for speed control, and that simply limiting the on/off ratio of the pulse would limit the average voltage to the motors, but as I said, I have the circuits, and the ones I have (UK and US) show no difference in the PWM control circuitry itself. There is a current feedback loop, which has a different sensing resistor for Europe (0.33 ohm) and for US (0.22 ohm) - and a startup compensation loop, which appears identical in both cases. So I agree with Andrew, and also with his comment that anything goes.
Roberts explanation is interesting - it also seems to explain why the European version suffers from damaged motors (I have three, all with internal shorts or open circuit (in the windings unfortunately). I appreciate the explanation of improved versions, but I want to remain with the existing system if possible - I have various spares, and a fixed pension
Joseph - I don't have the means to scan the circuits at the moment (and its a damn nuisance!), but I also have worked in electronics for many years, and can tell you the motor supply is definitely NOT run as a doubler. It has L&N connected to the inputs of a bridge (an S4VB as marked - also risky - its only rated at 4 amps). The positive output goes directly to the motor via the current sense resistor mentioned above (and a relay contact). The other side of the motor goes via the 2 parallel IGFTs to the negative rail. There are no large capacitors anywhere - none at all in the motor power supply - its a raw full-wave rectified supply.
The PWM switching IGFTS are switched by the PWM signal fed via two optoisolators to the IGFT gates. (I think one optoisolator turns the IGFTs on, and the other is used to speed up the turn-off - they are definitely NOT connected in parallel, or one to each IGFT). The 18V power for these IGFTs is also derived from the raw motor supply - just an R/C/Zener supply.
So as you see, a very simple circuit. It was the apparent lack of any obvious or failsafe method of limiting current through the motor/IGFT chain that prompted my question. Most of the failures I have had were shorts in the IGFTs, leading to the motors running flat-out with no speed control, or burned out motors - and now I am getting a better idea why. The IRFP450 has a continuous drain current of 14 amps, but its power dissipation is only 180Wmax. I believe the motor is rated at 3A (I stand to be corrected), so if a European motor is run at 180 volts, the power is going to be possibly over 500W (3 x180), which cannot be correct if the motors are rated at 250W, or even the newer 350 Watts - this suggests either a lower average operating voltage, or a higher current rating. It also accounts for the two IGFTs in parallel. It is not difficult to see that a stall condition could lead to high current, followed by IGFT failure, followed by motor failure - hence my questions about the motors.
Dave - you are quite right - I have a circuit for a motor controller which has the configuration you describe: the XMT 2335 fitted to Sieg C3 machines has this configuration - but as I noted above - I need to stay with the original configuration. The bridge rectifier in the FCXXJ series is just a simple silicon bridge - an S4VM in my case. I have seen a board with separate diodes fitted in place of the bridge.
Many thanks for the inputs - I'll go away and see what I can modify. (Been considering using an Arduino UNO to generate the PWM control, but its still a work in progress until I am happy with the motor power side.).
Edited By An Other on 28/03/2020 18:58:06
I have had a 7x12 'chinese' lathe and mill (X1 type) for many years now, and have had the usual trials of failing control boards and motors several times. I know there are many different motors/controllers fitted to these machines, but I refer to the older versions (I think 250W or 350W brushed motor)
While fixing these problems, I have collected various circuit diagrams and info relating to these machines, and as a result have a question:
The circuits for the European and American controller boards (for the lathe, for example) are very similar ( number is FC250J, but the same question probably applies to the uprated FC350J).
The DC voltage for the motor in these circuits is derived from a bridge connected directly to the incoming AC Mains - so in Europe this should be 230 x root(2) = 325 volts DC, and in America 120*root(2) = 170 volts DC. (I think).
There are some differences in resistor values in the control circuits from the two areas, presumably to compensate for this difference in voltage, but there appears to be no difference in the bridge DC supply for the motors, implying that a much higher voltage is fed to the European version. The drive circuit (via two IRFP450 IGFTs) is apparently identical in all the circuits I have.
Does anyone know if a different motor is fitted in the two areas? There seems to be no indication on the motors themselves. I ask because I think one of the motors I have came from the States, and I would like to use it.
|Thread: Thread heading looking weird|
A)......Is that intended to be a dig at me ?
B) ... or is it by mere chance that it immediately follows my post ?
C) Either way ... I have made no such 'definitive statement'
A) I do not understand why you should think I was taking a dig at you - I was simply pointing out a fact drawn from the posts I had read.
B) If you care to look at the timing of the posts, your post was 26 March, 21.53.07. Mine was a day later on 27 March 14.36.17 - hardly "immediately after' yours.
C) Where in my post does it say you made a definitive statement?. There are posts where statements have been made that certain software has caused the problem, but I would say that has by no means been proved at the time of the posts: I was simply suggesting more evidence would be useful, so that people who know what they are doing could perhaps provide an answer.
Rather sad that you feel the need to make such comments
This site may be some help to you: Link
Do people only read the last post in these threads or what? Several people have noted that disabling Adblocker has no effect - the problem is still there, yet people make definitive statements that the problem is due to Adblocker.
Maybe it is on your machine, but as someone else noted, it is worth noting your hardware/software/browser, then someone who know what they are doing may see the connection. It has happened to me, yet I have made absolutely no changes to my software, not even an update (and I don't use Windows, so it didn't happen in the background), but the problem suddenly appeared on my machine - I am more suspicious that some other site has done something I don't know about.
Me too, but not every thread, just some of them. Linux/Firefox, and only this forum.
Adblocker nothing to do with it - same effect withh adblocker disabled.
|Thread: A beginners locomotive|
Del - sent you a PM - An
|Thread: Keeping busy|
I have never had enough time to do all the things I want to do! - every day something else gets added to the mental list. Medical reasons caused early retirement (at 61), so me and the missus bought some land, built a house and have never stopped since (53rd wedding anniversary last year). I haven't even had chance to go hang-gliding yet. I genuinely have trouble understanding how people can claim they are bored - whatever that means.
I am more worried that when I finally kick the bucket, no-one will ever be able to work out what half the things I was working on are for - but then I suppose they won't care anyway - I guess I would go with Hopper in another thread on this forum - people are more important.
|Thread: Chinese Scales|
Don't know if this is the right place for this: I've been playing about making some modifications to some of these chinese scales, and came across something which may be of interest -
I have seen posts from people complaining that the battery life sometimes seems very short - on the 4 scales I am working on, the on/off button does not switch off the measurement electronics, only the display. This suggests that if you are going to leave these things unused for long periods, it might be a good idea to remove the battery.
The scales I am using are from 3 different suppliers, and do look different. Also the 'internals' are not the same, but all have the same power issue.
|Thread: Sieg X1L Mill Failed|
Circuit of older machines - might help -its the lathe, but very similar to mill.
Not sure if I am talking about the same mill, but long ago I had a small Sieg mill, and had exactly the same failure mode. The control board turned out to be the same as the type then fitted in the chinese mini-lathes - and there has been much discussion of their electronics on this forum.
Eventually I traced the fault to the power devices (not sure now whether they were transistors or power MOSFETS), which had failed. They weren't difficult (then!) to source new devices and replace, and it was considerably cheaper than the 80-odd pounds a replacement board cost at the time. It might be worth looking at your board, and searching this forum for info on the control boards for these chinese lathes and mills.
|Thread: Websites contacting you|
About a year ago I had a problem with my computer, which eventually led to me re-installing LinuxMint. Users will know that using the Linux Thunderbird email client can be a bit tricky unless you know the dodges - a new installation will lose all the previous emails, and your contacts etc. The trick is to copy the (normally hidden) default folder over from the old installation to the new installation, along with the older .ini files (or you can edit them) - I have done this successfully many times for new installations of Linux on various machines, or after software mishaps - you can also do this with Firefox - it saves having to go through complete setups after re-installation, and avoids losing emails you want to keep.
I have several email accounts, including a Googlemail account, all running under Thunderbird, so I copied over the files into Tbird, and all seemed OK - I could read the emails in Thunderbird.
Then I realised that some Googlemail e-mails were 'empty' - they appeared to exist, but had no text in them. In Thunderbird I had opted to save my emails on my computer, but I know that the original mails also remained on Googles server, so I opened my Gmail account directly so I could forward the missing emails to Thunderbird. I had done this procedure several times, and on other occasions only found relatively recent emails in Google - which I usually forward then delete - my Google mailbox is usually almost empty, because I hate leaving stuff in it. (I also empty the mail 'bin'.
Imagine my horror when I found EVERY email I had ever written or received in the Gmail account for many years - literally thousands of them - including ones I had deleted (directly) over the years from the Google account. (I am quite rigorous about this - all 'old', unwanted, unsolicited mails get deleted, I thought permanently - from the account - not in Thunderbird, but in Googlemail).
I immediately deleted the lot (I hope), but I have never received any explanation from Google, and since then, I have not seen the same phenomenon again - but I won't use my Googlemail account again - I don't trust anything they say or do - I don't really care what they claim they do in the interests of security, I simply do not believe them.
I think the moral is that even when you don't think your data is being copied, read and used - IT IS, all the time. Probably better to be paranoid than hacked and robbed, or your data stolen.
|Thread: Coal being phased out|
I must admit I read this thread, and was left wondering if it all makes any difference - where I live (somewhere in Europe), 90% of the populace burns wood for ALL heating. The wood is sourced from naturally grown forests, mostly oak and ash - when did you last see a naturally grown oak forest? There is NO replanting scheme, and although estimates vary, most of the wood is illegally cut - a huge proportion is taken by Austrian and Hungarian companies who export the wood illegally, after paying the appropriate kickbacks to local councils - this is all well-documented in the press and internet, and several reporters and investigators have been killed investigating this business - to make matters worse, these thieves only take the trunks - they remove all extraneous branches and the upper parts of trunks, and leave them to rot. I am sure I will receive comments rubbishing this - they will be wrong, it does happen, and there is no reputable authority here doing anything about it.
The remaining 10% of the population burns imported natural gas, at ever increasing prices.
A very small amount of coal is available, and perhaps it is as well only a small amount is available. If left outside to get wet, it develops a yellow powdery coat - I'm no chemist, but I have to wonder if this is sulphur. It certainly stinks of sulphur when it is burned.
So as you can imagine, the airborne pollution on a cold day has to be smelled to be believed, so its hard to believe that a small number of people using environmentally unfriendly heating systems in the UK will make much difference.
Apropos electric cars - can anyone explain clearly why generating electricity remotely and piping it to the vehicle is environmentally friendly? You will still use either fossil fuel burning or nuclear power stations to develop the amount of power needed for all the electric cars, yet society is gradually turning against both these methods of generation - or is it a case of 'out of sight, out of mind'?
|Thread: Drilling small holes in hardend steel|
|Thread: Old Computers - why do people bother|
Time is flying faster than I thought. I still have a working ZX81, a working Oric (2nd version) and a Dragon. I also have several 4004 cpus (even when new they were useless), several 8080s, and a Z80, plus various support ICs, like 8255s etc. The Oric in particular was very good, and it was very easy to program it yourself, using assembler. I replaced the 6502 CPU with a 65C02, which has additional instructions. At the time, it was possible to buy books with a complete commented dis-assembly of the operating system, and I wrote several home-brew systems for use in it - It also has a 'real' keyboard, which is a vast improvement on the 'dead flesh' keys of the first Orics, and Sinclair Spectrums - it was a pleasure to use by the standards of the day.
The computers were bought new out of interest, because at the time I worked on a satellite tracking system which used a Honeywell tank ballistics computer to control the antenna steering, and we used three Elliott 803s for data analysis, and it was interesting to see the development of new computing techniques. To confirm one of the other posts, the Elliots did have a hard-wired bootloader, which loaded a pre-prepared 5-hole punched paper tape. If my memory is correct, they had an 18-bit word architecture, and the 803s we had a 1 kiloword magnetic core memory. I had a colleague who wrote a workable bridge playing program to run on these computers, written directly in the Elliott machine code. Puts the multiple gigabyte installations of today into perspective!
We did some (unofficial) work to use a Commodore PET as a replacement for the tank computer mentioned above. This computer used discrete components for the logic, working in non-saturating mode to obtain the necessary speed - it worked, but was a real pain to work on. It was built in a cast aluminium case about 1 metre long x 50cms square, with forced air cooling - every time you needed to change a board, it needed dismantling, change the board, then put it all back together to test it - hence the attempts to use a PET. We always wondered how they managed to hit anything when they were used in tanks. (The PET was eventually used mostly to play a golf game, because the ministry wouldn't sanction installation of the PET in place of the Honeywell - but I learned a lot doing the work.
|Thread: Is there as Raspberry Pi expert in the house ?|
There is some adverse press about the RPi 4 suffering from overheating under some conditions. I can confirm that the earlier versions of PI do not have this problem. Various heatsinks/cooling fins are on sale to deal with this problem.
These might be a help - not all Rpi4, but might get you started - hope it helps.
This last also makes some realistic comparisons, as opposed to a 'wishlist'
Theres lots of other stuff around. It would seem that you need to be sure you have the latest RPi4 to be sure it will work as it says on the tin.
|Thread: Old Computers - why do people bother|
This question of 'Bloat' has had me puzzled for some time. I agree with Nick Clarke that adding new functions will inevitably inflate the amount the of code (given that the same language is in use), but I wonder sometimes whether the 'new functions' are always needed. As a long time user of Linux, even that has many functions and capabilities that I never use. I actually spend some time chucking out unwanted stuff when I make a new installation - my goal is to get to a 'Linux Lite' which actually has the capabilities I need and use.
I know different people have different needs, and I also know that Linux developers have spent a lot of time getting most Linux dialects to the point where they don't need endless user interaction to install, but I have often wished that I could select the bits I need. One example, which although probably not earth-shattering, is that the icon bars at the top of the page in LibreOffice are entirely a duplicate of dropdown menu items. There is a facility to edit the icon bars, so I tend to edit them out of existence - but the code is still there. Linux nowadays supports touchscreens and gestures - but I suppose I am old-fashioned, and use a simple monitor - I don't feel the need to sit stroking and gesticulating at it. There are many other examples.
I concede these are personal foibles, but I am using them as an illustration: this is what I would call 'bloat', so I would like the option to do without. My understanding is that Windows also suffers this syndrome to a larger degree than Linux. It would also seem to fit in with the growth in installation size from older generations to newer.
That said, a modern large disk is far cheaper (and allegedly more reliable) than the small ones of yesteryear, so does it really matter if the applications are huge? The machine I am using now has the OS on a 2TB drive, and I have a 14TB second drive in the machine, plus an 8TB external drive for backup of important stuff - its cheaper and more reliable to use a hard drive as backup, than to faff about with DVDs and CDs - I have many which are unreliable or even unreadable after a relatively short period of storage - bit of a nuisance if important backups on a DVD fail after a short time - I wouldn't back anything up to DVD these days.
And you could ask why people keep restoring and using antique cars, and historic buildings, and even old lathes and mills, and.....
|Thread: Ink jet printer woes|
And I thought I was alone struggling with Epson!. However, I would like to make one point in Epsons favour, but unfortunately they seem unable or unwilling to capitalize on it. Their older printers (my 4000 for example) do have these evil electronic monitoring chips which turn the things off, and up to a point I can see the reasoning: it does note in the instructions for the printer that the thing may stop printing if the absorbant pad which is apparently fitted below the heads becomes saturated with ink - they advise contacting Epson for (professional?) replacement - but you can't, because they won't answer qu0eries. I guess this does justify the cock-eyed reasoning for using the electronic switch-off (sounds like Volkswagen diesel cheater, doesn't it?).
But their later printers, such as the 382 and 3150 I mention are generically called 'ecotanks', and have large ink reservoirs which you have to fill from bottles of ink. When I bought the the 3150, it came with the three bottles of coloured ink, and two bottles of black. (If I remember correctly, they claim 3000+ black and white printings from a single refill, and I can confirm that the 382 which I managed to get going has already produced many pages. I also produce high-density PCB negatives using the printer, which uses 'lots' of ink, and so far there has been no need to refill the tanks). As far as I can see, these printers also have no electronic cheaters, so you can 'print' with empty tanks (confirmed) but they do warn you that this could damage the heads, which seems fair enough to me - but why no good driver for a widely used OS, and no scanning ability?
This was apparently in direct response to the complaints about expensive, restricted-life cartridges. I think this is a great idea, but has been ruined for me because they won't put a small amount of effort into producing an easily-deployed driver for Linux. Before someone jumps on me - there is an Epson LInux driver, but it is virtually useless - doesn't always install and work correctly, and has dependencies on deprecated and obsolete files - same for the scanner mode.
Now I will watch this thread to see someone justify why they don't need to produce a driver. Good luck to the WIndows users.
Don't want to hi-jack the thread, but thought a word about my problems with Epson and Linux might save someone a problem.
I originally had an Epson 4000 from long ago, which I really liked, but eventually I decided it had to go when the cost of the ink cartridges made a mortgage necessary, and also the 'disuse' syndrome drove me crazy having to clean the heads.
Like a fool, I went out and bought an Epson 382, with the large ink tanks (because I liked the 4000). This caused me endless problems. First thing was that Epson have stopped supporting Linux...or have they?. If you can finally find the right place on their website, which is a model of disorganisation and chaos, you can find Linux drivers. (The native Linux Mint drivers would not handle an L382 at that time). After much faffing, I was completely unable to get this driver to do anything properly - pages came out as a mass of characters (not graphics), and colours were a joke. Emails to Epson went into some black hole somewhere.
Eventually, in desperation, it was consigned to the junk pile in the spare bedroom, and (I really did have a bad senior moment) I thought 'it can't all be bad', and went and bought an Epson 3150, also the ecotank type.
Exactly the same problem with that - Epson site very unhelpful, drivers hard to find. While I was doing this, it seems that the Epson site underwent some renovation and changes, and suddenly I was able to find the drivers (for Linux). But they still didn't work properly. The site advised me that it was dependent on certain other files, which by then were virtually impossible to locate. Eventually I did (had to compile them first), installed them, started to install the drivers - and got a message telling me that the files I had just installed were the wrong version for that driver (but not according to the Epson site!). This printer was also consigned to the junk pile 'for later attention'
Back to the L382 - downloaded the drivers from the revamped site - and it worked!. At least, it works as a printer, although many of the settings are not possible - scanning is not possible, but I live in hope - perhaps with a little more tinkering....
Summary: Epson website is useless and disorganised. Epson does not respond to queries to their help pages. Despite claiming to support Linux, they do not, at least, not well). I am no amateur at this, but all my experience, plus much communing with various (non-Epson) forums was not able to sort these problems, A borrowed HP printer worked at first attempt, using the native Linux drivers - no more Epsons for me.
The idea is good - large ink tanks, with none of this electronic level crap, but unless you are running Windows, don't buy an Epson. Hope this saves someone a lot of grief.
Want the latest issue of Model Engineer or Model Engineers' Workshop? Use our magazine locator links to find your nearest stockist!
You can contact us by phone, mail or email about the magazines including becoming a contributor, submitting reader's letters or making queries about articles. You can also get in touch about this website, advertising or other general issues.
Click THIS LINK for full contact details.
For subscription issues please see THIS LINK.