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Member postings for Paul Kemp

Here is a list of all the postings Paul Kemp has made in our forums. Click on a thread name to jump to the thread.

Thread: Vintage voltage
22/11/2021 00:10:45

Well if the media are to be believed many are voting with their wallets and buying second hand cars now, as reportedly prices are going up. Is this a reaction to the deadline for new fossil fuel cars in 9 years time?

My poor old Discovery with the towing capacity I need is getting poorly, not sure what to do, certainly can't afford a new electric even if there were somewhere to charge it so not sure which way to jump!

Paul.

Thread: china/India - Cop 26
19/11/2021 21:29:11

Ok, I see how the figures Sam B1 is quoting could stack up on efficiency but running cost is another perspective that is probably more important to the average householder than efficiency. On the efficiency question the figure Sam quoted for generation efficiency is a little lower than my off the cuff guess but the transmission loss a little higher so ball park around what I was expecting.

In terms of cost the latest averages I can find for September despite the gas price rises put electricity per kWh at around 4.3 times the cost of gas. I also did a bit of digging on heat pump COP and it would seem that yes a COP of 4 or higher is achievable in ideal conditions but the norm is between 2.5 and 3.5 - so considering the high capital cost plus the higher running cost only the most dedicated of greens would be attracted.

In Dave's (SOD) example of heating use a heat pump system considering its apparent average limit of 40 degrees C on the hot side he would need to be running it considerably longer to get the same heating rise in the house?

Seems another example of the gap between environmental sustainability and economic sustainability to me. Granted price differentials may change between energy sources and legislation may drive change but if it's the latter there will be a lot of people driven below the poverty line.

Paul.

19/11/2021 00:49:21
Posted by Sam B 1 on 18/11/2021 23:12:12:

burning gas to make electricity and then using that electricity to run heat pumps is a far more efficient way to heat homes than burning gas directly; switching over to heat pumps allows our limited resources go much further

Have you any credible figures to back that up? Granted CCGT is pretty efficient but taking into account grid losses and then whatever the efficiency of a heat pump is compared to the efficiency of a new condensing boiler that sounds a bold claim?

Paul.

Thread: Not the time to be complacent about Covid
15/11/2021 22:00:29

Before relying on vaccines to protect you from catching Covid consider the following;

Vaccines give some level of resistance to infection, more importantly they offer protection from severe disease that may require hospitalisation or indeed mortality.

In some cases they can increase the chances of a very mild infection such there are no symptoms - this does not mean you cannot pass it on if so infected!

Vacination is a good idea to protect yourself from severe illness and potentially increase your immunity such that your chances of catching it are reduced. Being with another person that has been vaccinated is no gaurantee they are not infected, carrying or capable of passing on to you, in fact in some instances it can increase the risk they may be infected and niether of you know!

Paul.

Thread: loco won't run
12/11/2021 01:30:12

Hmmm I think you may have mentioned that ........ Once or twice. Ever the diplomat?

Paul.

Thread: Warco WM 16 motor
07/11/2021 18:58:43

No idea on that particular machine but I swapped the motor and control board on my Chester mini mill for a 3ph motor and cheap VFD for about the same price as a replacement motor. Never looked back it's far better than the original set up, standard motor used to get too hot to touch in about an hour, new set up will run all day. Lower power than yours but the motor came from inverter drive supermarket I think for about £50 and the VFD from a source unmentionable on here for a similar price, probably a death trap and not approved but it's worked fine and I am still alive! Best mod I ever did to it!

Paul.

Thread: Telephone / Internet Scams
03/11/2021 20:50:38

About the only really good thing I can say about our internet / telephone provider is we get zero nuisance calls. The first time any number calls us it automatically diverts to the screening process where the caller needs to record their name and purpose, it then calls us and asks to accept or reject, if rejected the number is permanantly blocked. It's a bit of a pain for genuine callers to hold while the process goes through but once accepted they can call freely. Since we signed up for this a couple of years back we have had absolutely zero scam or nuisance calls.

in fact it has made life a bit boring as I used to try and see how long I could lead them on and how much they got wound up when they twigged!

Paul.

Thread: Crankshaft Factory
03/10/2021 18:12:36

As stated, shot peening, common in crankshafts, normally at the fillet radius or other areas of high stress reversal. Idea is to introduce a compressive stress into the surface such that as stress becomes tensile the tensile magnitude is limited. Helps prevent fatigue cracks propogating in the surface of the material. Very important on cranks this process has been used on that the important areas like fillet radius are not machined when undersizing the journal or the benefit is lost.

Paul.

Thread: Not enoughh CO2 ?
27/09/2021 23:32:15
Posted by Michael Gilligan on 27/09/2021 23:02:15:

Posted by SillyOldDuffer on 27/09/2021 14:05:15:

[…]

This graph shows global temperature to be rising and is cause for concern because it appears to be accelerating in line with theory, which is bad, bad, bad for everyone.

globaltemp.jpg

.

Credit where credit’s due … Here’s a link to the NASA page : **LINK**

https://climate.nasa.gov/vital-signs/global-temperature/

… and a quick reminder of Lowess smoothing : **LINK**

https://www.statisticshowto.com/lowess-smoothing/

MichaelG.

.

P.S. __ if you want to play with different fits, the data table can be downloaded using the link below the Xaxis

With respect it was a genuine question. However you want to 'play' with fits of the curve the data sets themselves still show a significant trough around 1910 and a significant peak around 1942. You could manipulate the curve according to the data for the trough to be a little deeper and the peak to be a little higher but it's fine as presented, it still shows a larger short term variation than the period of reasonably steady increase say 1962 (ish) to present? Given the efforts to eradicate CFC's over the last 10-20 years coupled with efforts to reduce CO2 certainly over the last 10 years there is no real hesitation in the rate of rise. Hence my question.

Paul.

27/09/2021 20:31:16
Posted by SillyOldDuffer on 27/09/2021 14:05:

This graph shows global temperature to be rising and is cause for concern because it appears to be accelerating in line with theory, which is bad, bad, bad for everyone.

globaltemp.jpg

As climate deniers have successfully delayed attempts to reform our foolish ways over the last 30 years, humanity is stuck with the consequences. Robin thinks CO² helps his garden grow: I'm worried about the risk of Bangladesh flooding. There, rising sea-levels could create 163,000,000 refugees at the same time as North Africa becomes uninhabitable due to desertification.

When the experts predict Climate Catastrophe, they really mean it. I used to think global warming could be managed sensibly into a soft landing, now I believe the future is out of control. The milk is spilt. Prime Minister Macmillan was once asked why governments failed to deliver on their manifesto promises. He replied, 'events dear boy, events...' We are three square meals away from chaos!

Dave

Edited By SillyOldDuffer on 27/09/2021 14:05:54

Whatever was going on between about 1898 and 1910 we need to do more of? What caused the peak around 1942? What happened pre 1880?

Paul.

Thread: Heatshrink sleeving as a heat insulator for valve handles?
26/09/2021 01:41:21

Just do what the big boys do and use rag or wear leather gloves! Aside from that and following full size practice also, fit wooded handles.

Paul.

Thread: Recommend a grade of steel
25/09/2021 11:32:16

You say there was no hydraulic lock, how can you be sure of this? Have you removed the clack valve to the boiler and checked there is free passage? I have seen several boiler clack valves for pumps "fur" up on the boiler side reducing the area of flow, the worst down to a small hole little bigger than a pin, can be particularly problematic on steel boilers using treatment, especially if you add it to the tender. The reduced area significantly loads the pump. The fact you have effectively 2 failures simultaneously (pin and rod) suggests to me there is something else going on. You suggest the rod failure is about half inch from the weld - that suggests it the point of failure is well on the edge of any HAZ. Lastly if your engine has isolation valves at the boiler for the clack I have seen some clowns close these valves when the driver isn't looking! That never goes well if the bypass is closed, I know many people who keep the handles in the tool box to prevent bystanders "fiddling" with them!

Paul.

Thread: Not enoughh CO2 ?
22/09/2021 18:36:26

As ever there seems more behind this story than meets the eye at first glance. Most news articles are blaming this on record high gas prices with little explanation of the reasons for the high prices beyond increased demand due to emerging from the pandemic. However if you dig deeper there is a lot more to it. Gas reserves (gas in storage waiting to be used) are at a low, below 2018 levels, the figures don't show a drastic drop since restrictions have released / enconomy has recovered. But neither do they show a significant increase during the peak pandemic period which suggests there was little down turn in demand either. The lack of decreasing demand may be linked to lower than normal wind speeds across Europe leading to greater use of gas in electricity generation. Apparently reserves are low due to reduced export of gas from Norway and Russia (plus some allegations Russia is holding back supplies!). Norway and Russia combined, supply around 40% of European gas consumed. Previously in the UK and Europe when gas prices were high electricity was generated by coal powered stations - we all know where that has gone - few resources left and reliant now on imported fuel.

This article is the latest (August 21) I found with future predictions tells an interesting story.

https://www.worldoil.com/news/2021/8/6/natural-gas-prices-surge-as-energy-transition-driven-demand-outstrips-supply

For those unwilling or unable to follow the link a very broad executive summary is that gas has been seen as a transition fuel to zero emissions as dirtier fuels are being phased out however not being exactly clean itself there has been unwillingness globally to invest in new projects to increase the supply to meet the demand.

There is some irony here that the drive to green has produced a bonanza for the gas market with other technology lagging in implementation and capacity. The demand for gas is set to continue increasing and in Asia demand due to outstrip supply so the price issue isn't going to change any time soon! With increasing drive to electricity but without an exponential expansion in renewables to support, electricity prices are set to follow the current trend especially considering the steady increase in demand for electricity from ev's and similar initiatives (no gas boilers in new houses). Green hydrogen is no silver bullet either because a 20MW electrolysed only produces 3000t a year and there are not many of those plugged in right now.

Dont expect your bills to drop any time soon! The really odd thing in all this is CO2 is one of the pollutants we are striving to eliminate but is so widely used in the supply chain it is set to become more expensive - unintended consequences?

Paul.

Thread: Traction talk forum
20/09/2021 23:16:51

Thanks Andrew, I tried at 06.00 this morning and it wouldn't load, still the same tonight. Hopefully it's not terminal!

Paul.

20/09/2021 23:06:38

Anyone else having trouble logging in to TT today? Seems to have disappeared?

Paul.

Thread: Workholding Problem
12/09/2021 11:46:04

OP said he had a collet chuck, if that marks the smaller diameter it's not much cop. If the large diameter has run out when held in a collet either the collets are rubbish or the small and large diameters are not concentric anyway?

Paul.

12/09/2021 01:53:13

I must be missing something? Assuming the 3 jaw or collet on the lathe runs reasonably true if you hold it on the castellated spigot I don't see why there is significant run out? As the large boss to be machined down is also oversize I would just hold it on the small spigot and machine the rest, then it must be true to the small spigot. There are many instances where large diameter parts especially castings are machined by holding on small chucking spigots so I don't see a problem. If you are worried take light cuts. If you really want belt and braces put a small centre drilling in the face, reduce the large part leaving a small projection with the centre in and last op remove the tailstock and machine off the small remaining spigot. I think you may be overthinking / worrying too much. If it helps the casting (cast iron) for the smokebox door on my traction engine which is 11" diameter was machined holding it on the 1 1/4" chucking spigot with no drama!

Paul.

Thread: Multimeter recommendations
09/09/2021 01:18:03
Posted by Robert Atkinson 2 on 08/09/2021 21:26:07:
Posted by Paul Kemp on 08/09/2021 20:12:56:
Posted by Robert Atkinson 2 on 07/09/2021 17:36:49:

I think the fact it was new out of the box says it all. Presumably a manufacturing defect that was not picked up. Calibration is done with low energy sources for safety so may not pick up all faults. They cetainly don't test the fuse breaking current on every one or they would shi with blown fuses

What did Fluke say when you sent it back to them?

Robert G8RPI

I don't think it was a manufacturing defect, whe I said new out of the box that day it was that morning, the incident occurred in the afternoon. We had been doing a survey with the Class Surveyor to renew the Class cert and leccy had used the instrument on other tasks prior quite successfully both LV DC and HV AC. I suspect Andrew has it right, he simply had it on the wrong setting, it had been a long refit and everyone was tired. It never got sent back, we sailed the next day and never really found enough of it to send back! My point was they can be blown up.

Paul.

But that is the whole point. A meter that is CAT approved will NOT "blow up" even if connected to a supply (within it's rating) on the wrong range. A good one like a Fluke should not even have signficant damage, just a blown fuse. The fuse should not even emit a flame or sparks, that is why they are so expensive.
So either:
A. The meter was faulty nd should have been returned to Fluke if for no other reason than to ensure it was nor a defect that warranted a recall.
or
B. The system it was used on exceeded the meters CAT rating.

Note that the CAT rating is not just voltage, it the available energy i.e. the voltage and the source impedance. It you short out the mains at the end of a mains lead the energy is lower then if you d the same at the consumer unit This is because the resistance and inductance limits the current.
If the meter was being used on a main distribution board for a MW sized generator (possible on a ship big enough for classification) then it may have been being used beyond it's rating. Typically at that energy level the test leads have to be fused as well as the meter.

Robert G8RPI.

Well electrickery is not my deep specialism I was the engineer superintendent on the job, can only recount what I saw. Total available power was four 160kW generators if all on the board at once with the bus tie closed but ship maximum load 50% of the maximum power (100% redundancy) only 2 machines on the board at the time, bus voltage 415v 50hz. Whether a ship is classed or not hasn't much to do with size, this was an 86m ferry but Class can go down to at least 24m. Lots of small vessels are classed and many administrations delegate approval responsibilities to Class. I can't remember the exact test being carried out at the time, probably under or over voltage trips as frequency and reverse power trips were usually done from the board instrumentation, the volt meters on the boards were analogue and not that easy to read small variations.

Paul.

08/09/2021 20:12:56
Posted by Robert Atkinson 2 on 07/09/2021 17:36:49:

I think the fact it was new out of the box says it all. Presumably a manufacturing defect that was not picked up. Calibration is done with low energy sources for safety so may not pick up all faults. They cetainly don't test the fuse breaking current on every one or they would shi with blown fuses

What did Fluke say when you sent it back to them?

Robert G8RPI

I don't think it was a manufacturing defect, whe I said new out of the box that day it was that morning, the incident occurred in the afternoon. We had been doing a survey with the Class Surveyor to renew the Class cert and leccy had used the instrument on other tasks prior quite successfully both LV DC and HV AC. I suspect Andrew has it right, he simply had it on the wrong setting, it had been a long refit and everyone was tired. It never got sent back, we sailed the next day and never really found enough of it to send back! My point was they can be blown up.

Paul.

08/09/2021 00:24:12
Posted by Robert Atkinson 2 on 07/09/2021 17:36:49:

Why don't people READ posts?

OP wants a reliable meter, an ebay cheapie is not that. An analog is not really a practical general purpose meter these days..My personal preference would be a used Fluke but this does not normally provide the transistor tester requested and isn't new. The transistor testor is a bit of a gimmik on the very cheap meters.

If you wand a good new meter under £20 took at a Tenma 72-13440,

For the transistor tester get a £3.50 ebay meter but don't use it on mains.

Some will complain that my suggestion is manual ranging, but that is much better than a slow autoranging one.

Robert G8RPI.

I like your confidence that a Fluke won't explode. I was on board ship in 2015 working on a bit of kit close to the 415v switchboard. The electrician was doing something on the switchboard on a low step up platform stood on the switchboard matting. I am unsure exactly what he was up too but he was checking something on the main bus mounted in the top of the switchboard using a brand new fluke just out of the box that day, supplied with a calibration cert - purchased from the US Fluke dealer in the locality. Long story short there was a massive flash and a bang and leccie was on the floor still holding the two undamaged leads, from each was dangling part of the meter, the remainder was spread all around the space! I don't know what he was up too but he was a certificated ETO of many years experience, he didn't get a an electric shock but he certainly got a surprise shock, as did I! He repeated the task he was up to after he changed his trousers with the old meter that was out of cert and it went fine (identical model - I had purchased the new one as we couldn't get the old one calibrated quickly enough). There wasn't enough left of the meter to be able to tell with certainty what range or function it was set too! I guess there is always an exception to the rule but certainly they can be blown up!

Paul.

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