Member postings for Robert Atkinson 2

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

And how is anyone ele supposed to know this? If it's acessible it has t be safe without any special proceedures. CEE or HAN +PE connectors are good choices. Another option, similar to the HAN A is the Hirshman ST series. The STAK3N https://uk.farnell.com/hirschmann/stak3n/rectangular-receptacle-3-pe-way/dp/1176412
and
STASEI3N https://uk.farnell.com/hirschmann/stasei3n/plug-panel-3-e-way/dp/495025
make a auitable 16A pair for under £20.

The metal shell GX20 "microphone" connectors must NEVER be used fo any voltage over 50V, the design is not safe. That's apart from the fact that the cheap ones may not be well made. Only £15 extra for safety.

Robert G8RPI.

As I said, not all HAN connetors are suitable, only the ones listed as having a protective earth connection. The first picture did look like it had a longer pin (actually placed firther forward, the actual pin is the same.

As has been noted they come with crimp or screw contacts. If using a screen you ideally need a metal shell version and cable clamp designed for screened cable. You could terminate the screen to a wire and use 4+PE connector.

Yes that one pictured does.

The 5th pin at the top is longer than the others.

Not ALL HAN connectors do, They have to be nPin + PE or similar description to be safe for external mains power connectors.

Robert G8RPI

Edited By Robert Atkinson 2 on 12/02/2020 12:55:56

Correct, accessible connectors on voltages more than about 50V AC have to be "safe" which means earth making and breaking first (except for double insulated equipment) and touch proof power contacts on supply side. They also need to be correctly rated for voltage, current and environment. Typically this means a connector approved to some standard or another.

Connectors that are only accessible with a tool or key only have to correctly rated. This is because it's assumed only trained persons will have access.

Gene mentioned XLR connectors. while mains versions of these (mainly professional audio) connectors were (are?) available, they have not meet safety standards since the 1990's. This applies to many older designs like the "Bulgin" mains connectors. These can be used on existing equipment (or internally) but should not be used on new equipment and should be replaced with modern types if damaged.

Robert G8RPI.

Search for HAN A 3 +E they are a Harting HAN series A 10A 3 pin plus earth. Commonly available from RS Components, Farnell etc. Both RS and Farnell will take personal credit card orders.

Robert G8RPI.

Yes, they are safe and legal as long as they are the +E (earth type. That is the HAN connector I referred to in my previous post.

Robert G8RPI

100% second what @Steviegtr says. That metallic microphone connector is potentially lethal and is illegal to use on mains.. If you want something more compact than the "commando" type 3 Pin and earth connector suggested by steve, have a look at HAN connectors. Again you heed 3pin PLUS earth. This is subtly different from a 4 pin connector in that the earth contact is designed to make first and break last. This means if there is a fault and you are touching the motor as you unplug it to fault find the case cannot become live. The FEMALE goes on the FVD output , Male on the motor

An example is **LINK**

Other sources available

Robert G8RPI.

Edited By Robert Atkinson 2 on 12/02/2020 07:52:44

Person to person infection fully confirmed. One British national infected in several in France and England.

Masks and gloves are not 100% effective but they do help a lot.

Robert G8RPI.

Aviation is still mostly imperial but is slowly coming round to metric, It can't come soon enough. On pipe fittings, SMC pneumatcs came up with Unithread male fitting with a special thread form that fits G Rc, NPT or NPTF female. Sealing is by a captive gasket.

Robert G8RPI.

Well just to be odd I prefer PICs and a compiled basic, PicBasicPro. I started repairing equipment with Intel 4004's etc back in the mid 70's as a prt time job while still at school. Lot's of computers ofver the years. Did a lot on BBC B's, but Dragon, Oric, Sinclair Mk1, Apple II, Cromenco S100, HP 85. Apricot XI, Softy 1,2,3 and (currently), 4 PROM programmers. Used to build PC's for friends etc in the 80's and 90's but not any more.

Robert G8RPI.

Thread drift alert

What probability did you put on getting shot with a six shot revolver an one round? If it was 6 to 1 against you were wrong. With a conventional revolver, 1 round loaded and held upright the odds of the round being under the hammer when the trigger is pulled are much less than 6 to 1 This is because the single round unbalances the chamber and it will naturally tend to stop at the bottom.

Robert G8RPI.

Funnily enough I was on a Nimrod today, MR2P XV255 at the Norwich City Museum. I was picking up a small gas turbine engine (Honeywell GTCP36-150) that I bought. That's a new project to get going on.

Robert G8RPI.

The P8 is a proven design, anything Airbus based would have been a development project and the experience of the MR4A made that un-palatable. Any development project will cost more than an existing product. The P8 is based on the 737-800 with modified 737-900 wings, the -800 & 900 are Neo's not the MAX. The 737 is of course a devlopment of the original 707 so the design of some bits are a similar age as the Comet the MR4A was based on. Some parts of the the P8 are British. Foe example Marshall Aerospace and Defence Group make the auxillary fuel tanks that give he P8 it's extended range

https://marshalladg.com/our-stories/boeing-p8-tanks

Robert G8RPI.

These are my personal opinions and may not reflect the views of my employer.