Member postings for Robert Atkinson 2

I always wait until Ebay are offering a "Max £1 selling fees" promotion before listing anything that is going to sell for more than £50. I do OK on Ebay, I've bought a job lot of test equipment items for 99p buy it know (collection only) and sold 1 item from it back on Ebay for £1500. Seller also let me pick his skip, an item from there went to a dealer for £750, the listed on their site for 4 times that . The seller was closing down and had bee quoted a few hundred pounds for clearing his "hazardous" waste electrical equipment so was glad to get rid. I did OK , I've no problem with the dealer making a profit, he had to calibrate the item and provide a warranty and has premises and employees to pay for.

What annoys me is the people selling dangerous new goods or items that they know are not working properly. That works both ways, computer sellers in particular have trouble with buyers who have an identical faulty item, buy a working one, swap the faulty part and claim the one they bought was faulty.

Robert G8RPI.

+1 for the 1.5mm 4 core SY

https://www.tlc-direct.co.uk/Products/MF1dot5slash4.html

SOD and Pete are also correct about the braid. The braid in SY is not to be used as a protective earth conductor. It's main purpose is physical protection, but it will add some screening t reduce radio interference. The braid should be connected to ground at the VFD end only. At the motor end it should be cut flush to the sheath and insulated with sleeving or tape.
This stuff is part of my day job.

Robert G8RPI

There is no link out from the DVLA website (gov.uk) that I can see. BUT if you search for DVLA tax car on google an ad link to a site related to the one you had trouble with is top of the page.
I can't follow this due to protection on the system I'm using at the moment but it could be a less clear webpage than their main one or even a 3rd party. Perhaps this is what you went to. The SCAM sites are set up to look like the official ones. If they have a page like that then it is improper.

I particularly dislike the amount of click bait and ad links we get bombarded with.

Robert G8RPI.

Having had a quick look I actually I would not call that a scam site. They have the costs clearly marked and are providing a service. Problem is the service costs £5.95 a month and most if not all of what they provide it is available on line for no charge. Dubious value but not an outright con.

Robert G8RPI

Not just a good idea, it's essential that you earth the motor and the metal frame. Earth wires shold only be green/yellow (or the bare conductor in fixed wiring with a green yellow sleeve). Never use brown, blue, red or black for an earth connection.
1.5mm2 should be OK for this application if the saw is supplied by a 13A plug.

Robert G8RPI

Looks like another ill thought out "knee-jerk" reaction to "help" the environment. If cheap wood and coal are restricted there will be even more people burning rubbish like treated wood, painted wood and bonded products like chipboard and MDF producing even more pollution. Wood burners may be a pleasure for some users but may not be for those downwind, especially if they have asthma or other respiratory problems.

Using electricity to directly heat water for a central heating system is just nuts. A air water heat pump is a better option.

If we are going ahead with all this electrification we need a good amount of new nuclear generation capacity for the near and mid term, but no one seems to be doing anything about that. New generation fast reactors that can "burn" part used fuel and stockpiled depleted uranium would be a good option.

Robert G8RPI.

You removed "or carry it around" leaving just the car part.

I just quoted the law on made for or adapted items, I did not say that a grinder met that test.
You are just reading what you want to see, not what is there, I won't be responding further to this.

Edited By Robert Atkinson 2 on 20/02/2020 20:03:51

I stand by what I said, please don't edit what I said to suit your case.
While guidance is that there will normally not be any action without intent, the lettter of the law does not require it. The law (Theft act 1968) also says that possesion of an item made or adapted for burglary or theft is considered intent on it's own. Obviously the case of one in your car depends on you being in or near the car and not at home.
The point of the wording of this law is that it's does not need proof of intent, if it did it would be too hard to enforce. It's basically up to you to show reasonable cause for having the item.
Hopefully it is applied with reason, but you could end up on the wrong side. Try not to fail the "attitude test" for startrers. Finally it's not the police who decide what is an offence or who is guilty.

Robert G8RPI.

Don't keep one in your car or carry it around. You are committing the crime of "going equipped" or to be exact

"A person shall be guilty of an offence if, when not at his place of abode, he has with him any article for use in the course of or in connection with any burglary or theft."

Applies to a lot of tools of course but battery grinders are used a lot for theft including bikes and catalytic converters.

As this is a 12V pump you will need a power supply. Using a variable supply is a much better way of controlling the flow than throttling the output.

If you only have a fixed 12V supply and are throttling the output, try putting a 12V lamp in series with the motor (start with a 21W brake light and swap to a 45/55W headlight if not enough pressure.) This will provide a near constant current supply to the pump, reducing flow (speed) but maintaining torque and thus pressure as you throttle the output. using the lamp will produce less stress on the pump and reduce power consumption.

Robert G8RPI.

The 1:1 drawings are called "Lofts", produced by "Lofting" This was done in the available large open space - the loft.
A key part is drawning curves with flexible strips called splines held in key points using weights. Used for boats long before aircraft.

Robert G8RPI.

DIY EDM

https://www.instructables.com/id/EDM-Electrical-Discharge-Machining/

Robert G8RPI

Edit.This is North American and was connected direcly to the mains supply. If trying this you MUST use an isolation transformer.

Edited By Robert Atkinson 2 on 17/02/2020 10:22:53

That will be a Mill tooth / curved cut file. Used for fast cutting softer materials like aluminium alloy and commonly used for shaping body filler.

Robert G8RPI.

If there are no lights or noise from the PC at all it is likely to be a fauly PSU. That is not a good enough reason to scrap a 5 year old PC unless you were thinking about changing it anyway. A new PSU is under £25 and there is no reason why you could not replace it yourself. If you are anywhere near Cambridge I can do it it for you.

Robert G8RPI.

Have you tried putting the Hard Disk Drive into an external USB HDD enclosure? These are cheap and will let you access the drive if it is working at all. There are two types of HDD used in most PC's IDE and SATA. The IDE type is older and fairly rare now, The IDE uses a 40 pin ribbon cable and the drive will have two rows of 20 pins, The SATA uses a small cable and the connector looks like plstic with no visible pins. Obviously the external case must be the same type as the drive.

Robert G8RPI.

What computer? What operting system?

Desktop / Laptop /All in one?

PC / Mac / Linux

Make and Model

OS version?

With this information we can give you some checks to do.

Robert G8RPI.

It's not just the slower speed you get with a VFD and 4 pole motor. Smoother torque delivery, lower noise and more torque are big advantages.

Robert G8RPI.

Hi,
Not knowing the MD65 I can only address item 1/
I recommend going for a 4 pole motor and make sure your VFD can go up to at least 100Hz output . This will allow you to achieve the high speed on the occasions when you need it and give better torque at the lower speeds you use most.
The fan speed issue is a bit of a red herring, for the same spindle speed (and belt/gear reduction) the fan will be at the same speed regardless of a 2 or 4 pole motor so the relative cooling will be the same. Depending on the actual spindle speed and gearing one may be closer to it's nominal speed than the other so the airflow will be closer to it's design point. The 4 pole motor will be close to this at half the original maximum speed so again has the advantage if you mostly use medium or low speeds.

Robert G8RPI.

Nigel B,

You are correct that most of the connectors you named do not have compliant make/brake firs earth connections (some do) However most of the machines these servomotors are mounted on will have alternative earthing connections and / or the connectors are not accessible when the machine is powered. Additionally what was acceptable 20 years ago, never mind 40, is not acceptable now.
Maintaining a earth during connecting or disconnecting is not an advantage, it is a requirement.

Gene and Ian,

Mounting a VFD on a machine is not acceptable unless it is in a suitable enclosure. They are not inherently protected against the ingress of swarf or liquids like coolant. Every drive I've ever looked at the installation instructions for said it needed to be protected against such hazards. Most require an enclosure to comply with safety requirements regardless.
If mounting on a machine you also have to consider the effect of vibration on the drive.
In all cases you need to read the installation manual and follow its requirements. If the VFD didn't come with a proper manual it's probably not going to be compliant with the regulations.

Robert G8RPI.

Dave (SOD),

The idea of passing the interlock through the connector is a valid one. It will however only be fully satisfactory if the interlock pins disconnect before the power pins. It would be even better if the interlock was low voltage.

Old Mart,

It dosen't matter if it is personal use or public access, if anyone (partner, children, siblings, friends) can access the plug it must be a safe design and installation. Even if you are a complete hermit in the workshop it still should be.

Mgmbuk,

I missed your comment on the GX16 /GX20 / microphone connectors. The manufacture's raing of 400V and 5A is irrelevant if the connector is not designed for safe mains/power use. The GX20 have a number of issues apart from the lack of a make first / break first earth connection. The creapage / clearance distances are not adequate, they have unsupported solder connections, they have a metallic body with no secondary isulation or means to connect a protective earth. The stated insulation resistance of >1000 megohms is just nonsense, particuarly for a mated pair, and there is no tst voltge stated. For most the quality is poor and they are likely to fall apart with vibration.

Robert G8RPI.

Edited By Robert Atkinson 2 on 12/02/2020 21:20:55