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.
Thread: Todays Mystery Objects? |
07/09/2023 07:52:54 |
Hi Michael, I sent you a private reply. Robert. |
Thread: Acetylene bottles in the home workshop |
05/09/2023 20:06:43 |
+1 on making sure your insurance company knows and it does not affect your cover. This has practical guidance: Transporting it is another matter, again check insurance. HSE have an interesting video that includes the planned rapid dissassembly of a old Fiat van. Robert. |
Thread: Pre-Paint Degreasing |
04/09/2023 19:14:30 |
Brake cleaner or acetone Robert. |
Thread: Compressor question |
04/09/2023 10:47:23 |
What Clive says, but you really only need to "Tee" the normally open depressurising (unloading) valve into the large pipe between compressor and tank. The pressure switch can be connected to the tank port with the small pipe that currently feeds the pneumatic unloaders but you will have to remove the existing pressure regulator in that line. Robert. |
Thread: Old bearings never die... |
04/09/2023 10:37:37 |
Requirement seems a little obsessive to me. Certanly during the working life of the aircraft they would not have bothered about the make. That is why there are standard size designations. I've actually received "refurbished" certified aircraft bearings where the two races had different manufacturers (VC10 flap drive thrust bearings). It was queried with the supplier and they confirmed it was acceptable. Robert. |
Thread: 2 pole or 4 pole for Myford ML7R |
01/09/2023 21:13:37 |
A steel gland that directy contacts the mesh (screen or armour) on the cable and is fastened through the metal box is the ideal solution. No other connection to the mesh / screen is required in this case. The matal case must of course be connected to mains earth. The inside of the box under the gland nutsmust be free of paint or similar finishes. Robert. |
Thread: Scams |
31/08/2023 15:40:02 |
Posted by Martin King 2 on 31/08/2023 11:38:04:
Szabina
Ok I'm buying On the other hand, I will make your payment via UPS EXPRESS delivery
Nearly always eastern European names offering the relevant courier to bring me cash and take the item away, sometimes offering a £20 extra to reserve the item.
Cannot quite work out their angle?
Obviously we decline their kind offer......
Cheers, Martin
Typically the payment method allows the money to be withdrawn after you have parted with the item. To add even more they sometimes send more funds for you to pay the courier. So you loose the item and the cash you paid the courier. Variations been going on for years even before the internet. Robert. |
Thread: The beginning of the end for Copper telecomms |
31/08/2023 15:33:28 |
SOD, Sorry if I was not clear. I was referring to internet connectionsa (VOIP) and cellphones having common failure modes, not POTS and VOIP / Cellular. I'm fully aware of how the POTS works. POTS is required by law to provide a universal service (waiting time not withstanding) and back-up power. Cellphone and IP services don't have these obligations. Robert. |
31/08/2023 09:18:46 |
Starlink is Low Earth Orbit (LEO) so the need for a low angle view to the south (UK) to "see" a geostationary satellite over the equator is not there. As long as you can see a reasonable amount of sky it should work. Robert. |
Thread: 2 pole or 4 pole for Myford ML7R |
28/08/2023 16:47:38 |
Hi Duncan, In a properly set-up VFD system using the E-Stop input will stop the machine faster than the normal stop button. As they say it has a filter built in you probably don't need an external one. Robert. |
28/08/2023 13:32:23 |
A metallic case also reduces interference. You can use an ABS box but you should fit the VFD and any filters onto a metallic plate that is then installed in the ABS cox. All earths, includng cable screens / armour, should be connected as directly as possible to the plate. Ther are two disadvantages to putting the E-Stop in series with the normal stop input: Robert. |
26/08/2023 15:14:10 |
I can't comment on the paramrters as I don't have the same model drive. For the E-Stop, yes just use the NO contact. Robert. |
Thread: 24V rectifier for lighting. |
25/08/2023 18:30:53 |
As I mentioned earlier, it also depends on the nature of the moving object. A facetted item like a hex bar or the jaws of a chuck can be frozen by much lower light levels if the pulse coincides with a reflection in the irection of the viewer. Yes even less likely but still a problem when it does happen. Nealeb, Yes you would think the phosphor would broaden the pulse of a white LED. However it's not the case. Some time ago I was looking at alternatives to short gap xeon strobe tubes for a new analytical instument. Out of dilgence rather than expectaion it would work, I tried some phosphor type white LEDs. I was shocked at how fast they were. The turn-off was much faster than even an electrically quenched xenon tube. Note that a lot of LED lights specifically use pulsed outputs. The human eye responds to peak light levels so for the same power consumption a LED operated at a 50% duty cycle with twice the current will appear brighter than if operation on all the time. Robert. |
Thread: Assembly diagrams - how are they done? |
25/08/2023 12:27:58 |
You thought twice before putting Rotring to film. It's not a click of the undo button to change once the ink is down. |
Thread: Raspberry Pi Pico |
24/08/2023 20:47:19 |
Here is an interesting comparison. A modern car contains around 100 million lines of software code. A passenger aircraft has about 15 million lines. Robert. |
Thread: 2 pole or 4 pole for Myford ML7R |
24/08/2023 20:07:25 |
Hi Chris. You should have an isolator. If the power socket is eassily accesible then pulling the plug covers this. I like to put a IEC 60320 C13/14 "kettle lead" plug and socket on the enclosure so you can instantly see that it is unplugged. Robert. Edited By Robert Atkinson 2 on 24/08/2023 20:08:16 |
Thread: Eclipse E225 scriber |
24/08/2023 19:56:03 |
Well I just bought one of the NOS E225s at £4.99. That's less than a replacment steel tip for the E220. Thanks for the tip (pun intended) Robert. |
Thread: Electric motors |
24/08/2023 17:31:14 |
The connectors on the chinese motor control are sometiems called "aviation" connectors. This vendor To make thing worse. They have used a MALE connector on the OUTPUT to the motor. This means there are exposed pins with high voltage on them when the motor is unplugged. This is a serious shock risk. Robert. |
24/08/2023 16:43:55 |
Posted by mgnbuk on 24/08/2023 15:34:06:
Is it the particular metal body connectors used on that Chinese drive that you are not happy about Robert ? All the Indramat, Siemens & Fanuc servomotors that use cable mounted connectors (rather than connecting boxes) I installed used metal body connectors. Nigel B
Yes. The connector on the chinese unit are a type designed for low voltage DC. They date back to at least the 60's. A common applictaion was micropones on CB radios and the like. Robert.
|
Thread: 2 pole or 4 pole for Myford ML7R |
24/08/2023 08:11:55 |
I'd leave the maximum frequency (speed) at 65Hz. This gives you a bit more operating speed range but is well within the limits of your 50/60 Hz motor. As an aside, often the best utility can be had from a motor/VFD set up by arranging for the motor to run at higher speed than it's name plate rating. This is why I recommended, and fitted on my own ML7, a 6 pole motor. On a VFD this motor can easilly run at 4 pole motor speeds. It has the same rotor, bearing and fan construction as the 4 pole. It prodces more torque at low speeds than a 4 pole. I also fitted a larger motor pulley to reduce stress on the belt. The revolution for 50 Hz probably only affects the RPM indication or parameters set in RPM. It should be set to the value for your motor but does not affect actual operation of the motor. Robert. |
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