Weather Warning for Hobby Machines

In the past few months with extreme cold/wind/rain, we have seen an increase in sales of spare parts such at brushed DC motors and control boards, for hobby machines, especially in the U.K.. We are starting to see this for a small number of brushless motor and control board variety too, but not as high at the brushed variety.

It is our opinion – based on years of monitoring reasons during such period, that this is mainly based on power surges, especially in rural areas – where we have seen the most sales for these spares. In certain urban areas, as the demand for heat ‘keeping warn’ has increased during the extreme weather, there are power surges too – for example, at our warehouse where we have monitored 263v at times, along with brown outs.

To help reduce replacements due to these surges, we would like to make the following suggestions:

• Invest in a cheap surge protector plug from somewhere like B&Q – probably cost around £5.00 to £10.00. This has to be specifically for the machine. This is regardless of you having RCD, other equipment which runs OK over the same extension, etc..
• The cheap surge protector plug will last in the event of one or two failures before giving up the ghost. The more expensive ones may last longer, but this is not an area for which we have knowledge. All we know is that investing in a surge protector may help to reduce chances of greater, more expensive damage.
• In cold weathers, warm up the machine by turning it on at low speed for a small period of time, before use.
• If you are not using the machine for long periods of time, and if your machine is in a cold shed, it always helps to turn on the machine and keep it on at low speed, from time to time. This can help to stop cold/damp setting in. This especially applies to machines where the motor is exposed / hanging outside the machine, exposed to the elements. Try to avoid doing this during advertising breaks of popular programs such as Coronation Street, when chances of power surge are high, as kettles boil water for tea!. This is not a joke. It especially effects people living in an end of terrace house.

NOTES:

1. The above comments effect the majority of small machines of this verity on the market, regardless of them being from Tom, Dick or Harry, and regardless of them being fitted with super-duper ‘American specified’ DC motor controllers.

2. The matter has nothing to do with ‘fit for purpose’. Most machines from reputable suppliers comply with regulations in place. If such a question is raised, we in turn would question the possibility of ‘un-regulated dirty power’ in the U.K.

3. The above weather warning does not address the question of damage resulting from knowingly or unknowingly abuse of the machine by failing to use within its limitations.

4. General faulty component is also a possibility for failure of a control board, but we have seen more failures resulting from NOTES 1 and 3, in our experience, for the machines we sell.

Ketan at ARC

Thank you for the warning, living in the N of rural Scotland we have a lot of these problems. worst are sudden high voltage surges. I have the surge protectors on computer, and heat pump but they do not fully protect. Lathe is old belt drive and not so far affected. Any one know of better surge protectors ?

Interesting comment. I have a Oxford lathe with 3/4 Hp single phase motor. When the lathe is cold, I power it up with the belt tensioner in the slack position. This will allow the belt to slip but the chuck to rotate. I leave it like this for perhaps 5 minutes allowing the bearings etc to warm up a little before any serious work commences.

I also leave the drive belt slack whilst tapping and sometimes when reaming larger bores, there being enough power transmitted for a safe operation.

We are currently in a cold snap so the air is dry. In a few days it will all be replaced by warm(er) wet air. This will penetrate everywhere, even closed boxes and especially the ventillated housing for your control board. It will condense water onto your electronics. Rather than turning on a cold machine to warm itself up which may short out the board I suggest a small permanent heater directly underneath the controller. This can be a modern light bulb as though people lament the passing of the 60W bulb as a heater the replacement 10W is actually just right for this application.

I write specifications for the purchase of several million power adaptors each year. The mains spec we use is higher voltage and variation than normally supplied for the rest of the world because the UK supply is different although everyone talks about it as "240V".
A sceptic might say that if they creep the voltage up your standard 1kw fire uses just a bit more which is money in the bank for suppliers.

Valid point Bazyle. We did consider this condensation issue too. So we checked our sales records combined with weather. The warmer wet weather by itself did not create such damage resulting in any segnificant sales for such spares. Most of these small machines are also sold in the tropics, built in Shanghai for SIEG which sits in a natural wet/damp warm geographical depression. Many of the competitors factories are based in Anhui/Changzhou/Jiangsu region - west of Shanghai within 200~300kms, and the machines dont seem to suffer as much there. We kept coming back to variable high voltage surge, rural locations, extream weather especially cold - rural or urban, as the main causes.

However, it does make sense to warm up a cold workshop/machine especially if the machine is in an un-insulated workshop/shed. I guess that whatever one can do to avoid damage is helpful.

Ketan at ARC.

Hello Gordon,

Don't know enough about good surge protectors to make a clear suggestion.

Around here - Syston - Leicester, we have power surges every few days, and they increase during bad weather. We use UPS's for each of our computers - about 8, and a seriously heavy duty one on our server. The server is in my office, and every time there is a serge in the area, I can see the lights on the UPS coming on/going off indicating abnormal supply. This one even maintains some kind of log, in case we need to do a printout for insurance. Not sure if the printout will be enough though to suggest/prove anything to the insurance company / electricity board!

We also have the UPSs connected to the demo CNC machines. I don't know if that is an answer to your question, or if it is an overkill. I also don't know how old machines such as yours are effected or not, as we have no experience of such machines.

May be the electronics bods on here will have a better idea.

Ketan at ARC

Thanks for advice, I'll get a few of these cheap surge protectors bought.

To tackle the condensation I now use a 25w ceramic vivarium basking lamp under each machine table/bench. The bulbs are about £5 each delivered and fit a standard light fitting. I never turn them off, and when my machines aren't in use, they always have a breathable sheet and heavy blankets or covers - this ensures they're always slightly warmer than the next bit of metal! The heavy blankets only go on after a week of not being used to allow time for any moisture to evaporate from water based coolant in nooks and crannies.

The only adjustment I have made is to not use the built in suds tank on my lathe bench (learnt from experience here sadly), I have a small (2/3 gallon) steel tank next to the machine now. This way I don't evaporate the water based cutting fluid up the drain pipes where it is almost trapped inside the blanketed machine.

I also have a dehumidifier on 24/7 but set to >70% humidity with a permanent drain outside, as with most electronics most of the energy is converted to heat eventually so this is basically a 120w background heater that dehumidifies as it goes, overall this puts the background heat level to about 200w in humid condition, to 75w minimum in dryer times - and always maintains a slight warm bias towards the machines and anything stored within their cabinets.

I don't know if I'm going way over the top, but I also but cheap blue tissue roll on beds etc and spray with a 50%50 parafin HLP32 mix so a nice lightly oiled tissue is left on the machines..... to paranoid?? (my machines are spotless so far bar the coolant evaporating which was only minor!)

Quite. As Bazyle pointed out it is warm humid weather following cold weather that causes the problem. During a cold snap the machine cools down. When the air is replaced by warmer air, even if not very wet, the machine temperature can remain below the dew point for some time and condensation occurs.

Regarding cheap surge protectors, they do just that. They protect against a short time surge such as a voltage spike occurring when a heavy load is switched or due to a lightning strike to the ground. They do not protect against sustained high voltage as you describe however I would very much doubt that a 263 V mains would do any damage to a well designed controller.

Russell.

> A sceptic might say that if they creep the voltage up your standard 1kw fire uses just a bit more which is money in the bank for suppliers.

the same sceptic might even suggest that is why the UK keeps with 240V when every piece of equipment sold in the country for the last 20-30 years has to work on 230V.

Neil

I do understand and take your and Bazyl's point regarding going from cold to warm humid weather, causing condensation. As I said earlier, Bazyl has a valid point, and I respect Bazyls knowledge on the subject, with further clarification from you.

The ~263v in our premasis are short and sharp spikes when it happens, rather than a gradual increase - sustained. I do not know much about electronics so I respect what you are saying, but I do know that before we put in the UPSs, we managed to damage at least two HP industrial grade computer power supplies and hard discs. Thankfully, we have a service contract with HP. Once the UPSs went in, no computer failures resulting from spikes. Why they damage cheap machine controllers too, especially in the U.K., I dont know. I also dont know how well designed the controllers are. Some people, competitors and certain customers make a big deal about 'American designed' controllers being fitted to their cheap machines as a reference to reliability. Yet, even though we do not sell such boards, we get calls from customers who have such boards fitted, which have failed too!. They may or may not be well designed, with the price 'cost' base of a cheap machine. Not a debate I wish to enter into, as it is endless and well covered over the years by many on this and other forums.

The aim of my post is to try and help owners of these machines to avoid damaging their motors and boards during these bad weather times - a weather warning, be it for machines purchased from us or others. I regard your and Bazyls comments as constructive helpful comments.

I feel that by putting on cheap surge protectors on a cheap hobby machine may still help to avoid greater expense. The comments I am making result from questioning customers over the years, then asking for advice from certain people with some knowledge about electronics for simple solutions. I am sure that this is not the only solution, and it may or may not work in all cases. As a seller of machines and electrical spares with reasonable profit , the only thing I can gain from this post is 'good will'. By a customer spending £5.00 to £10.00 with B&Q for example, to save his/her machine, I potentially loose sales of motors and control boards. Generally, I get less warranty claims, and more sales for these boards for other competitors machines which share the same electronics. I also know that ALL other machines in this hobby arena face the same or similar challanges in the U.K.. If we are going to question the quality of a controller, one should also question the quality of power.

Ketan at ARC.

Edited By Ketan Swali on 19/01/2015 18:26:27

UK electricity supply is 230 V +10% -6%, Europe 230 Volt +6% -10%

240v was dropped a while back.

.

Would it help if the circuit boards were encapsulated / potted in some way.?

I am not familiar with the layout of these boards so doing so may cause further problems with not allowing circulation to heatsinks etc.

I may be wrong. ...................... But I seem to recall an areosol product being available that was like a kind of varnish to guard against such things as condensation an electronic boards. Connectors and heatsinks are masked before applying a thin coat of the product.

As for the power surge I feel that this may not be the full story. In the UK our mains is very stable compared to many. Perhaps somebody in China needs to recheck the specs of the components they are using and how they are using them.

Perhaps the implimentation of the above simple mod with the fitting of **LINK** Or similar ( there are many types available ) at your warehouse before dispatch would give you a good advantage over your competitors.

Best regards, Nick

Edited By Nick_G on 19/01/2015 19:56:34

Totally agree with you Bob, with regards to what it should be. But sadly it is variable in the U.K., above the 230V +10% + dirty with spikes at times in places across the the land.

Ketan at ARC.

When I have to replace a part on the occasional board at work I have to remove a varnish like substance so that I can get a cleaned area to remove and re solder new parts.

Martin P

Hi Nick

The board debate has been endless. The quality of components may or may not be a contributing factor, but I am a 100% sure that the UK mains are not so well regulated across the land.

The link you have given could also help. Will keep in mind. Thanks,

Ketan at ARC.

Hi all,

With regard to the filters pointed to in the link, these are not intended to protect from voltage spikes or brown outs, but rather to prevent interference from the apparatus connected to the mains supply being fed back into the mains.

Every computer, washing machine, TV has something similar already built in to it, since it is required by law now.

The device that is required to suppress voltage spikes is a "varistor", these are available at places like "RS Components and Farnell Electronics" and are quite cheap. However unless you have the knowledge of how to apply them and the skill to fit them the devices that have them already built in them are a safer option.

> UK electricity supply is 230 V +10% -6%, Europe 230 Volt +6% -10%

> 240v was dropped a while back.

Only on paper! The truth is those figures let Europe supply 230V and UK supply 240V, so no real change.

But from the time the voltages were 'harmonised' all UK appliances have to be able to work on European voltages.

Fact is we are supplied about 5% more volts and as heating is resistive heating costs are proportional to the SQUARE of voltage. That means we pay roughly 10% as much to run the same resistive load (e.g. a heater) as they do in Europe.

I have heard tales of UK supply being well out of spec from professional electronic engineers. I found this on the net:

"When the engineer tested the boiler, then a ring main socket and finally the consumer unit the readings were all between 280 - 290 volts! On consulting a couple of independant electricians, both asked the same question - are you close to a sub-station? There just happens to be one within 10ft of the house. I was advised to call the electricity board at once; I explained the scenario and they said an emergency team would be sent out within the hour. An hour later I wandered outside to see if anyone was looking for my house and found 3 engineers already inside the substation; I asked if they needed to come into the house and they replied 'maybe'.
5 mins later they knocked on the door, tested the consumer unit and declared the voltage was reading -surprise,surprise - 236 volts and my CH engineers meter must have been faulty!"

Neil

Most electrical household appliances such as washing machines nowadays have electronic speed controllers. Homes abound with electronic devices, many connected continuously to the mains. I'm an electronics engineer by profession so perhaps my house has even more! I have never had any experience of a fault in any of these caused by a "power surge" or voltage spike from the mains. At my office we have probably well over 50 computers, all with switch mode power supplies and probably the majority live 24 hours a day. In previous employers the numbers have been even bigger. Not to mention the quantity of test gear also switched on all the time. Except in server rooms these machines are not supplied from a UPS, nor in a professional electronics environment do we find it necessary to fit surge protectors. Again I have not been aware of any systematic problem caused by the mains supply quality. This is in a small science park in rural Cambridgeshire.

Most of these products, or at least their power supplies, are made in China or other parts of the Far East, but nevertheless function well on UK mains supplies. Since almost all of them have an IEC mains connector they are clearly designed for a global market and must take account of variable mains quality.

On the other hand what is notable is the number of reports on this and other forums of breakdowns of the speed controllers of dc motors on Far Eastern-made hobby machine tools. You can draw your own conclusion, but my opinion based on observation and a degree of professional experience is that the speed controller design is substandard and should be fixed. It isn't rocket science as it's clear that other companies making all kinds of domestic products have mastered it.

Is it only me that can do the maths then ?

230 + 10% = 253 so how can 240 have been dropped if it's with limits ?

Hi,
I'm one half of a pair of semi detached and historically my neighbour heated on night storage heating so was allocated Yellow phase and I had connection to Blue but we both share the common neutral line over some 50 metres of overhead line to the roadway. There are several crimped joints down this length and about 18 months ago we started to get browns and brights at random times.When I was bright he was brown and then vice versa
I spotted that we could control it to a degee by switching a fair size load (cooker) on or off, called the Western Electric in and they diagnosed one of the crimp connectors gone high resistance (damp getting into them). In effect the neutral line was no longer clamped to 0 volt, it was floating depending on which of us was drawing more current. I saw 280v at this time on my Aldi meter but after the repacement joint it all went away(until another crimp gives way, but then W E said they would have to close the A road whlst they fitted a new run without joints across it ) I suspect some of the fluctuations you see are from these sort of line faults.

Bob D