Member postings for Robert Atkinson 2

Correct, according to published figures my DPF equipped 150hp 1.9 turbo diesel Fait produces less particulates than the wifes 2.0 140 HP petrol (and 3 years younger) Ford. The new direct injection petrol's are worse for fine particulates than the old ones.
One thing has not been mentioned is that most people seem to think that the proposed ban on new petrol and diesel car sales means we will have to buy plug-in electrics. This is not try, Hybrids will still be sold and I'd guess initially a lot of those will be "light" ones with most power from the IC engine.

Robert G8RPI

Edited By Robert Atkinson 2 on 12/07/2019 07:25:41

The DIN connector is for the controller to stepper motor connection. The power seems to be a standard cylindrical power plug. These come in several size especally the centre hole. If @Steve Crow can tell me the OD and ID (gaugig with a pin or drill shank is best) of the plug and if it is positive or negative centre (should be marked on label) I can sen you a suitable NOS quality supply (Laptop "soap on a rope" style) for the cost of postage.

The controller does have to be CE marked for sale (or use unless personally inported) in the UK / EU. As it has a microprocessor it needs to meet EMC directive and even if it does not need to meet machinery, LVD or LVD it still needs the mark to confirm this. Unfortunatly most small importer in niche markes either don't know or don't bother.
The controller without PSU is $50 cheaper so that would buy a proper supply like
https://uk.farnell.com/xp-power/vet30us240c2-ja/adaptor-ac-dc-24v-1-25a/dp/2708291
even without the cost of the 120V adaptor.
I don't recommend buying mains powersupplies on ebay/amazon/banggood/aliexpress as you have no idea of the quality.

Robert G8RPI

(This stuff is part of my day job I'm a Chartered Engineer and have done CE/UL/CSA compliance)

Edited By Robert Atkinson 2 on 10/07/2019 19:32:29

That, on it's own is not suitable. It is a component, not a consumer power supply. To be safe it needs a housing, power inlet connector (or properly strain relief on the cable), fuse and output connector as a minimum. IT probably needs n EMI filter as well. Just sticking a mains lead on this is down right dangerous.

Robert G8RPI.

First thing first,

It is ILLEGAL for a UK company to supply a US only specification power supply for use in the UK.

The best option is to get a proper UK approved power supply. The 120V converter is rated at 45 VA (Volt Amps) this means only resistive (or PF=1) loads can be at the full 45 watts. The 120-24V supply is only 24VA output an input is likely to be 1.1 times this. BUT its an electronic supply and these have very poor power factor so VA at the input is likely to be well above 45VA. Add in the fact that we are 50Hz and the mains voltage is likely to be nearer 240V than 230 The little converter is over stressed. It is also probably an autotransformer and the 24V supply is only rated at 120V there is a shock hazard if the neutral of the transformer or it's connection fails.
I'd be less worried about a 24V 1A supply on a notionally 2A stepper motor because the controller is likely to limit the current and may even have a switch mode regulator that will increase the current available. What plug is on the controller end of the 24V supply? I almost certainly have a supply that will fit this and is properly designed and approved.

Additionally, is the controller CE marked? No disrespect to Bryan Mumford but I'll bet it's not. Again it's illegal to sell this in the UK unless it meets the required regulations and is CE marked. In this case at least the EMI regs apply to the controller and LVD to the power supply.

Robert G8RPI.

Robert G8RPI.

Presumably the same aircraft is over Bar Hill right now I. I concur with your P-47 Thunderbolt identification. eep front fuselage and harvard-esque tail are key. I then googled P47 UK and found this

http://vintageaviationecho.com/thunderbolt-returns-to-uk-airshow-scene/

which pretty much confirms it.

Robert G8RPI.

Edited By Robert Atkinson 2 on 07/07/2019 19:04:56

As said earlier, nanometer resolution is completly different from nanometer accuracy. I used to be one of the designers of machines that put 100,000 spots (100 each of a 1000 different samples) of DNA on 25mm x 75mm microscope slides 200 slides at a time. The feedback for the linear motors had 1 micron resolution. Accuracy was checked with a Renishaw laser interferometer which had nanometer accuracy and included compensation for the effect of air pressure and temperature on the laser light.
The arraying tip (split tungsten pin) position was compensated for thermal expansion of the frame and drive system. A traditional positioner like a CMM was not fast enough, we had a peak axis speed in excess of 3m/s.

Robert G8RPI.

Sorry Dave, but that's just not true. Modern electronics are not long life. The reduction ic size is the biggest problem as it causes higer power density and voltage gradients. The most common failure compnent is electrolytic capacitors.Many have specified lives (at max rating) of only a few thousand hours. Electronic failures are the most expensive repair on modern cars. This is not helped by technicians who just change boxes.
I have laptops that are twenty years old and still working fine. more modern, faster slimmer models from the same manufacturer have only lasted 3 to 5 years.
The USB outlet sockets fall between regulaton and all of them draw some stanby current. By physically having components they must be more of a fire hazard than a simple socket. They also add to the background electronic noise.

Robert G8RPI.

Mick said " Maybe we should all buy a 3 foot long yankee driver and bin the Bosch lol "

About 15 years ago I used to take machines to trade shows in the USA, The machnes were shipped in crates with lots of screws to open them . Having got fed up with short battery life on the cordless drivers back then and restrictions on carrying spare bateries on aircraft, I bought a yankee. Never goes flat (but you can wear out) and has automatic increased contact pressure with increased torque so hardly ever slips. Numerous people would come over and say " that's great, I'd fogotten about those" or similar. Not cheap but a great tool.

Robert G8RPI.

I use Xcelite which are available from RS Comoponents e.g.

https://uk.rs-online.com/web/p/screwdrivers/2550519417/

but even then they are extended range.

Snap-On sell a set of L type ones but they will set you back about £150

Robert G8RPI.

It's not just simple Phillips / Posidrive. Two fairly common variations are the Japanese JIS which is close to phillips but less pointed. Then there is Supadriv which neither Phillips or Posidriv fit properly. JIS headed screws are often identified by a dimple on the head.

More esoterically there is RIBE/Polydrive (used on FCA nd GM vehicles) and Spline which look a bit like Torx. As an aircraft engineer I have also had to deal with Bristol spline TorqSet, Triwing and Hi-Torq.

Robert G8RPI.

Edited By Robert Atkinson 2 on 05/07/2019 19:33:22

Are they original Apple chargers or aftermarket items? Both the charger(s) and the Lead(s)?

How old are they and what condition are they in?

It sounds like a glitch in the communications between charger and device. For a full fast charger there is "intelligence" in the device, lead (lightning) and charger. Unplugging resets the electronics in the charger and lead.

The spark you are seeing is from the EMI filter capacitor. While shorting it should not cause damage it would be better to just leave them unplugged for 5 minutes.

Robert G8RPI.

SOD raises a good one " lack of imagination" this seem very prevalent these days. I deal with failure analysis and environmental / performance testing as part of my day job. Few engineers seem to be able to imagine what might go wrong or the consequences of the failure,. Some of it is down to experience, but they don't seem to be taught what my wife (an educator from the USA) calls "critical thinking". Many just accept any old rubbish on the net or even data/specification sheet. If a tolerance /rating/ performance figure isn't on the data sheet it's probably because it's not very good. A classic and repeated, electrical one is the metal clad "25 Watt" resistor which is only rated at about 7W unless it's on a foot square aluminium sheet or similar heatsink and even then gets to over 100 degrees C.

Curiosity starts at an early age and I think it's wrong to restrict it due to mis-placed safety worries.

It's also not just schools that restrict use of machine tools. As an "office worker" My employer says I can't use even a pillar drill because I don't have the correct "skill code" and enforces it by locking up the tools. This is despite being a qualified engineer (OK avionics, but the formal training did include machine tools) and using a fully equipped prototype machine shop at my previous employer.

Robert G8RPI.

Edited By Robert Atkinson 2 on 01/07/2019 12:53:17

At 300mm between centres and a MT2 tailstock on the SC2 there should be no problem turning 6" between a chuck and centre. lots of choice in MT2 centres. why don't you think you can do it?

Nothing new there. Lots of variations on this out there. Mostly for bigger magnets. This one is quite nice

**LINK**

that's more of a challenge as to how you capture the data without affecting the pendulum. A high frame rate camera and software would be one option. A more interesting one would be line CCD or diode array sensor like those used in document scanners sensing the shadow of the pendulum rod. This would give better resolution, easily 1024 positions, and require less processing. The sensor and lens from a flat bed scanner would probably work as is. Disconnect the sensor from the mechanical drive (initially leave that is as is for home and end sensors) and just try the scanning software. The image should be a sine wave.

I just realised I made a mistake on the OCXO accuracy. 31.5 seconds per year is 1x10^-6 if it all went out in the same direction at the beginning of the year. A more typical 1x10^-9 average is 0.03 seconds in a year.

Robert G8RPI.

Deleted

Edited By Robert Atkinson 2 on 16/06/2019 21:50:34

The PICTIC I linked to (corrupted by smiley) "http://www.ko4bb.com/doku2015/doku.php?id=precision_timingictic" Google KO4BB (O not zero) pictic to find it

is ideal for what you want. run it from a 10MHz OCXO and a optocoupler obscured every pendulum swing and it will send the time of every swing to a PC via the serial port.

Robert G8RPI.

For a lowcost time interval counter with logging on a pc for checking clocks etc see

http://www.ko4bb.com/doku2015/doku.php?id=precision_timingictic

Robert G8RPI

Any decent OCXO will be accurate to 1 part per million in a year (<1x10^6, HP's 10811A is more than 10 times better than that) so that's 31 seconds in a year worst case. Over shorter time scales eg days it's typically a thousand times better so 0.001 seconds per day. How good do you need?

Robert G8RPI.

I agree totally. Of the dozen or so cases it's probable that most are from own dogs. We get lots of complaints about dog mess in the village newsletter but few about the bottles, glassses and drink cans (cans get shredded by the councel mowers into razor sharp pieces). I reguarly pick up bottles and cans on the greens and playing fields. Septicemia kills hundreds in the UK every year so a cut while playing is potentially much more dangerous than dog mess. I am biased, I had septicemia from a cut in a park as a child and am a dog owner and ouy dog has had to have vet visits twice due to a cut paw.

Robert G8RPI.