Here is a list of all the postings Robert Atkinson 2 has made in our forums. Click on a thread name to jump to the thread.
There are various versions of "SX2". For starters what motor type, brushed or brushless, does your mill have?
If you don't have athe skills to work it out for yourself, unless you can find someone who has fitted the exact same tacho to the exact same mill you would be better of using the hall and magnet supplied.
|Thread: Generating force to cap beer bottle|
I missed Jed's post as it crossed with mine.
|Thread: 3 Phase in a Model Engineers workshop|
If the isolator is tripping as you say " The isolator for the mill is a Telemecanique and is the one I used in Oxford. As it is the trip on this isolator that keeps tripping " and is the blue/grey bok on the wall (left side) I suspec that it is mis-wired. Many have a 240V coil and require a connection between one phase and neutral.
There are a few possibilities for mis-wiring. Common ones are:
There is also a posibility that the mill has failed electrically in storage. Possible causes are damp and rodent or insect activity. Do you have a multimeter and a insulation tester ("megger"? If so check the phase to pase resistance of the motor windings and phase to ground for motor and wiring.
p.s. I looked at Transwave's information on converters and was surprised how biased it was.
|Thread: Generating force to cap beer bottle|
American "screw-top" beer bottlles are really "twist-off". They are still crown caps like traditional bottles and put on the same way. The difference is in the neck of the bottle.
I'd go for off the shelf bottle cappping machine, windscreen wiper motor and a spring. Have a number of spring attachment points on the lever to change applied force.
Edited By Robert Atkinson 2 on 13/06/2020 10:42:31
|Thread: Compressor inspection|
The 250 Bar/liter limit is not to do with how long it takes to empty, it's an energy limit. Less energy means less damage if it fails. Steam has no lower limit becaue of the additional heat energy and the possibility of superheated water being present which releases even more energy as it boils when the pressure is released. Google BLEVE (boling liquid expanding vapour explosion)
The regulations on pressure equipment at work apply when the product of pressure and volume exceeds 250 Bar Litres. So a 250litre receiver has to be inspected if it operates at more than 1 bar at 10 Bar (~150PSI) 25 litres an above have to be inspected.
|Thread: How to glue plastics|
There is no point guessing what the plastic is you need to have a better idea. Looking at the photo I think Polyethylene is unlikely to be the material, it is too soft to make a ridid wheel lik the one shown. A couple of quick checks could be carried out on a sample (one of the remaining teeth would do). First is to try disolving it in an aggresive solvent like acetone (nail varnish remover if you don't have the pure kind). If it softens or dissolves it's unlikey to be PE, PVC or polypropylene and can for your application be glued with epoxy, just abrade the surfcae well.
If it does not dissolve try the tests here:
If the wheel runs on a shaft, whatever plastic it is, if you cut LH and RH grooves in the surface an epoxy would probably make a adequate mechanical joint regardless of surface adhesion. There is big surface area and the joint is in shear both of which are good for a bonded joint.
|Thread: Knob required|
A picture and dimensions of the shaft it goes on would be useful. As Rod said, 1/4" is easy but a lot of industrial switches use odd shafts.
|Thread: Single phase to 3 phase motor conversion.|
That capacitor is maginally rated on Voltage, 3 minutes on 220 V or 1 minute at 300V. UK mains is nearer 240V than 220V depending were you are. As Clive says they have very short life. Ideally the capacitor should be non polarised but these are larger and more expensive. The one you linked is effectiviely two 200uF polarised (electrolytic) capacitors conneted in series positive to negative.
Better again would be two 220.127.116.11 60 uF 450 V at £17.50 each wired in parallel (more capacitiance, less current through each capacitior.
Best of allis wire for Delta, fit a VRD and weigh the transformer from the old converter in for scrap.
Edited By Robert Atkinson 2 on 04/06/2020 08:22:31
Well that circuit applies 180 degrees to two phases (should be 120) and about 90 to the other. not an ideal situation.
|Thread: Surface Plate & Height Gauge recommendations|
Work threw one in the skip last year - literally The Rennishaw touch probe was still attached but smashed up aginst the edge of the skip.
|Thread: Arduino/Stepper Motor Dividing Head|
Part of the UI problem is related to the "Maker" approach to electronics where things are built from ready made modules like Arduinos, stepper drivers and serial LCD and switch modules. This makes it easy but limits variation and customisation. Unfortunatly it does not build understanding of the basic principals or skills. I've seen electronics magazine projects using breakout boards and screw terminals so you don't even have to solder.
|Thread: Soldering Iron|
What sort of "small jobs"?
If electical / electronic I'd recommend a temeperature controlled iron in the 30-50W power range.
Problem is decent ones are expensive and a lot of the cheaper ones are cheap nd nasty.
|Thread: Machine Tool Peripheral Hoists|
I do note that the standard SkyHook tool post mount has a dovetail to fit directly on a large quick change toolpost. It is the youtuber (Adam Booth) who has had it modified to go in the slot of the tool holder.. The Dovetail mount is probably OK on a big lathe, but the tool slot with two set screws is just not an acceptable design. There is just too much leaverage trying to roll it out. As a minimun an adjustable "foot" opposite the lug that goes in tool post to react rolling forces into the cross slide or mill bed woud be a worthwhile improvement.
|Thread: VFD speed control fault|
This is most likely to be a failed or failing electrolytic capacitior. Less likely is a resistor failure. I assume there is no circuit available for the internals of the VFD so a bit of detective work wil be required.
You could use an external 10V supply but the failing supply could still be used internally. Worst case thi could result in an uncontrolled overspeed condition.
Where are you located?
Edited By Robert Atkinson 2 on 29/05/2020 17:17:47
|Thread: Earthing Issue on new machine|
Hand held appliances with properly implemented Class 2 (double insulated) protection are safer than similar Class 1 (Earthed) appliances as an undetected insulation breakdown is less likely than an undetected earth conductor fault. A second breakdown of the basic insultion is required in either case to cause a hazardous condition.
If the lathe tool has NO electrical equipment, including switches, lights DRO's etc, mounted on it and the only connetion to the motor is an insulating belt there is no requirement for the Lathe to be earthed. It is still good practice though. It's the fault current path that matters. If the motor was mounted on the same metal stand as the lathe but not directly on the lathe then both the motor case AND the stand must be checked for earth continuity, but the lathe would not have to be. If bothe the motor and stand are earthed there is no series fault path to the lathe. In practice of course the lathe would almost certainly would also have some earth path to the stand due to it's mounting.
Note that there are two types of RCD socket, Active and Passive. You should use an Active type for machine tools etc as the trip on mains failure so act as an additional no-volt release preventing unexpected re-starting.
Passive types should be used for things like freezers that must re-start automatically.
Edited By Robert Atkinson 2 on 29/05/2020 08:14:45
1/ I knew what you ment, but "Class 1 PAT" is not clear.
2/ I sver said anything aout the supply (that does come under installation test) I described the means of connection. If the connecton to the supply has a plug it is considered "portable" as far asr PAT goes, if it hasn't got a plug it's fixed and PAT does not apply. Typically a physically fixed machine with plug would have longer times between inspections than something movable with a fixed connection rather than a plug (these are rare but not unknown).
There is no such thing as a "Class 1 PAT" defined by regualtion. Indeed there is no such thing a defined PAT.
There are Class 1 APPLIANCES these are those with a protective earth.
Portable Appliance Testing is normally considered to cover any electrical applance which plugs in. This includes industrial plugs, not just 13A ones. Fixed equipment regarding electrical testing applies to the supply, not the mounting of the equipment. Thus a Mill that is bolted to the floor but has a CY cable and a Commando plug going ito the wall is "portable" but pistol drill wired to a switched fused outlet is not.
A 20A earth bond test on a piece of electronic equipment will NOT damage it unless the equipment is faulty or test is carried out incorrectly. I've done or witnessed dozens of these on "portable" equipment that contained lots of electronic including servo drives.
A insulation test on a piece of electronic equipment will not damage it as long as the equipment is not faulty and test is conducted properly including selection of appropriate test voltage. A "Hi-Pot" (high potential breakdown test) does have a good chance of damaging electronic equipment but they are not appropriate to routine in servce testing.
There is NO legal requirement to carry out PAT.
I said don't get me started on PAT (especiallty not " PAT Testing" which is testing a test)
Edited By Robert Atkinson 2 on 28/05/2020 17:49:28
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