Member postings for Robert Atkinson 2

I was not implying that all chinese items are junk, but this is

The metal bodied connectors used for the motor power and feedback are not safe for use on the voltages that the motor runs on.

Trouble is people ignore the rules due to "normalisation" of the supply and use of non-compliant items - until someone dies then the fertiliser hits the air mover. Then there is a clamp down or / and knee-jerk legislation that also affects the people who were doing the right thing as well as the chancers.
An example of this is the proposal to make e-bike compliance subject to 3rd party review. This will add cost and delay to market for responsibe manufacturers whose bike wrer already safe. The chancers will just print false documents. I've seen this with pulse oximeters. Bought one that was CE marked an had a notiifed body reference. On checking it turns out thet notified bod don't do pulse oximeters

Robert.

Yet again cheap chinese junk that does not meet UK or EU safety standards. I can tell that just from the images. The connectors on the motor are not safe for use at the voltages that the motor runs on. Tha input voltage is not compatible with UK mains. The markings are not in english.

Buer beware, this could kill you or someone else.

Robert.

While Noel's answer isn't wrong per-se, he does not have the required information to determine the fuse size required. The fuse in the plug is there to protect the cable. So to know the rating you need to know the size of the flexible cable used. If a 13A fuse is fitted then 1.25mm2 or 1.5mm2 flex must be used. If 1mm2 flex is used then a 10A or smaller fuse must be fitted.

While noting that a 2.2kW VFD is a bit oversized for a 0.75kW motor, a 5A fuse would be adequate for the actual load of your system. I would still use 1.25 or 1.5mm2 flex for the mains input though. This is to minimise voltage drops. The VFD try to supply the required power so if the voltage drops the VFD will draw more current causing more voltage drop. This can lead to instabilites and reduced performance. Ideally you would use a 13A fuse in the plug with 1.25mm fleax and then put a 6.3A T ceramic fuse in the VFD enclosure before the mains filter.

Robert.

There are two significant employment differences in the USA that probably improve their productivity.

They are very much Hire & Fire. Much less job security. demaond goes down, get rid of some staff.

They generally have much shorter holidays and less generous sick leave provisions. When I tell people in the USA how much leave and paid sick leave I get they are very surprised.

Robert.

I fully accept that any BASIC is not what you should start to learn IF you want to be a prpfessional programmer, but I still maintan it ahas a place. Mostly for the reasons SOD said ( Our posts crossed so I didn't see his before hitting "add" on mine.

I'm going to get on my soapbox now...

One of the "things" I have against Arduinos, RPi's (and a lesser extent Python generally) is the "loads of pre-written stuff ". This allows people with little understanding to "make" things. The quality of the things is variable and if it doesn't work its hard to troubleshoot. It also, IMO, normalises bloatware. It cetainly does not promote understanding and efficent use of the available hardware. I'm sure I've mentioned the C comms libary that used all the memory in a PIC when my PBP code used the built in hardware UART.
I have the same issue with electronics "designers" who use modules for everthing. Often these are low cost things from the far east with no proper specifications or instructions. I've had supposedly qualified electronics engineers who could not design a 12V regulator because they awways bought a £2 module off amazon or ebay. When I pointed out that even the 1000 off price of the regulator chip on the board was more than twice the cost of the whole board they didn't see an issue. I immediately think the chips are fake or a lower rated part re-marked.

Rant over.

Robert.

The Pico is a bit overkill for many projects. It is a lot of processing power for the money. A lot of that is of course taken up to run Python. Making it simulate a Arduino needs a lot of third party software and seems a bit perverse to me. I certainly would not want to use it for anything critical. I must admit I'm a bit anti-Pi. I find the relationship between the charity, profit making company the mony they actually spend on charitable efforts, the niumber of directors and their relationships a bit troubling. As is the fact that their terms and conditions are business to business, i.e. no consumer protection.

I use "bare" Microchip PICs with a compled Basic. Pic Basic Pro www.pbp3.com which has a free version for personal use.

Robert.

No, it's a real issue. The phosphors in fluorescent tubes vary depending on type, colour and make, but most do not have significant persistence. So they will cause strobe effects. LED lights will too. IT's all dependent on the design of the light(s), what other light is present, the speed and optical proerties of the moving part.

Trouble is that the conditions for "freezing" a moving part don't happen often so we forget about it until an accident happens.

Robert.

Not my thing but saw these on ebay:

www.ebay.co.uk/itm/155729677014

A lot of unmachined loco wheels low start, collection from wolverhampton.
No connection with or knowledge of the seller. Buyer beware.

Robert.

Low voltage lamps were used on machine tools and as inspection lamps fpr two reasons:
Safety. Even if the moving and more exposed parts that may be damaged became live 24V is not a hazard.
Lamp life. Low voltage fiiament are lower electricalresistance and thus thicker. This gives longer life and better vibration resistance.

Care is needed when buying low cost mains powered machine lights (or making our own). Even just looking at the photographs of many on ebay show they do not comply with UK safety regulations and probably are not safe in practice. Nor having a proper UK mains plug and only two core cable are big red flags.
Yes you can make a class II (double insulated) lamp with metal parts and no earth. But it requirescare in detail design, material choice and manufacture. Add in the requirement for vibration resistance in normal operation of a machine lamp and it is difficult to acheive a suitable standard. Much better to use low voltage.

Robert.

A machine tool used by a business does not have to be fitted with guards under uk law. The employer must ensure that they are safe. Of course if they think they are safe without guards and here is an accident they may be in trouble.

As the club mentioned seems to have found, one of the big drivers for safety complinace is insurance company inspections.

Robert.

Looks like I was right. Google is your friend:

https://swissinstruments.com/my_products/diacator/

Robert.

Edited By Robert Atkinson 2 on 20/08/2023 09:27:18

The lever below the DTI translates sideways movement of the probe into vertical and pointer deflection.
The clever bit is allowing the dial to remain stationary.

Robert

Those would be thermal lances not Thermite. Interestingly the reverse reaction with iron.
Thermite is iron oxide and aluminium powder. A thermal lance is a steel tube filled with iron rods and fed with oxygen. Thermite reduces the oxide to iron and a thermal lance oxidises iron.

Robert.

Edited By Robert Atkinson 2 on 19/08/2023 18:54:56

Edited By Robert Atkinson 2 on 19/08/2023 18:55:13

That was Thermite not a furnace. The gas torch was just pre heating the rails.

Welcome to the forum.
Thanks for letting us know your outcome. Often the original poster never responds with th outcome wihich sometimes make you wonder if it is worth taking the time to post an reply.

Robert.

The lamp pictured is not compliant with UK regulations. Additionlly a metal bodied lamp with a two core mains lead is problematic. The 220V rating ia also incorrect for UK. I'd need to examine it but I bet it has multiple safety issues. Note that despite being UK stock the contact info is in China so good luck with support or getting your money back.

Robert

The light rating is 27W input power so 1-3Acdepending on voltage. Clearly intended for vehicle use confirmed by the R10 approval. It must have a built in regulator to work over this voltage range. While the peak voltage of 24V AC is out of the noinal range of the lamp, as mentioned by SOD, the loaded average votage is probably OK. To be safe just use half wave recification (1x 3A or higher rated diode) and a larger smoothing capacitor, say 1000uF or 2200uF 35V.

Robert.

To answer the question :

For your Sealy 27W lamp the current draw will be over 1A so you need a 1.5A or greater bridge rectifier. I'd suggest a 2 or 3A item. If using individual diodes to make a bridge then you can use 4 x 1A diodes like 1N400x series. This is because each diode is only carrying current 1/2 the time.
For capacitor you only need a minimal amount for simple electronics a rule of thumb is1000uF per amp of load. So for your lamp 470uF is adequate. Voltage rating needs to be at least 35V. Even 100uF would probably be enough to stop strobing at 100Hz.

Hope this helps.

Robert.

Edited By Robert Atkinson 2 on 19/08/2023 10:38:34

Bigger brings greater mass and inertia. This can be a benefit or detrement depending on application. Good for constant running with variable not good for frequent stopping and starting.
BLDC has a lot of advantages but it's not perfect. Not an issue for us but they don't like high temperatures. For machine tool use they have to be well sealed or ferrous particles will foul the magnets.

To be clear the people with experience almost certainly are Competent and would legally be able to do the work. The issue is when the work has to be notified. This is normally done throgh a registered body. You have to meet their requirements and pay a registration fee and annual membership fee. It's all about the money. In theory they could do it through their local council building control officer but in practice the time and cost involved make this impractical.

You CAN change fuses and make minor repairs and additions in your own home but there are specific limits.

Robert.