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Member postings for Phil Whitley

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

Thread: CovMac Lathes
02/01/2015 20:21:43

cracking good work Bob!

Thread: Electric motors
31/12/2014 21:36:48

Hi All,

John Stevenson, looked at the videos..................it is a bit slack compared to a fully automated factory isn't it! When were these videos shot, any idea?

John Haine, "a stationary motor doesn't have zero slip,it has 100% slip" that is not what I said, what I said was that a motor (with the power on) with zero slip, will be stationary, not quite the same thing, but you end with my point exactly,

"Of course with 3 phase drive all this goes away and you get constant torque"

Thank you!

Phil.

30/12/2014 20:16:05

I am not going to labour this point, I would suggest that anyone doubting what I have said should google it! There are many sites out there that explain the difference in efficiency far better than I can.

Neils statement that "A bonus is that three phase motor produces constant torque at all points in its rotation, a single phase motor produces 'lumpy' torque, and that three-phase loans itself to electronic speed control"

Is getting near the point. If you consider a single phase sine wave, it passes through the zero line three time in a complete cycle, and at these points, no power is developed. In a three phase system, because the cycles are 120 degrees apart there is no point where the power output is at zero. If we introduce artificial 3 phase systems to the argument, we see the power consumed by the artificial 3 phase generator of whatever type lessens the efficiency of the whole system, although with modern equipment, not by much.

John Haine, I have read your second paragraph several times, and you seem to be in broad agreement with me apart from your statement that the slip creates the magnetizing current in the rotor. If slip was required to do that then a stationary motor being that the only motor with true zero slip is stationary, and would never start. The magnetic current in the rotor is induced by the field current which then attracts the induced pole in the rotor to the pole in the stator. as the rotor moves to try and reach the pole, the pole is already decreasing in power, and the next pole increasing, so that in effect the rotor never catches up, and the difference between them is the slip. As the rotor is loaded the slip increases marginally up to the point where the loading overcomes the torque, and the motor begins to slow. As you say, once this process has begun it is self destructive of the torque. The "shear" I was talking about was the initial point where the slip has increased to the point where the rotating field first becomes unable to drag the rotor round.. I think basically we are saying the same thing in different ways. For a more thorough explanation, see http://www.engineeringtoolbox.com/electrical-motor-slip-d_652.html

"There are complicated reasons why 3 phase motors are preferred" I would love to hear them! the simple reasons are that they are more efficient, more reliable and simpler to start.

I honestly didn't know about Brooks, I knew they had become Brook_Crompton which included many other companies as well, and also knew they were a Hawker Siddely company at one time, I will take your word for it, but if they are Chinese owned, they are certainly not shouting about it on their website. The problem with this type of takeover is that the resulting group eventually becomes so big that it fails, and is snapped up by the competition, usually foreign, who are simply purchasing a share of the market. Once the home industry is destroyed in this way usually by heavily government subsidised competitors from outside the accursed EU, then the market is supplied from cheaper places to manufacture (see John Stevensons post above)and the profit leaves the UK forever, along with the unpaid taxes that multinationals are so good at avoiding. It is ok to buy out, amalgamate or otherwise do a deal with your competitors as long as you are all in the same marketplace, you have the same costs and overheads. Foreign competition however, (especially when government backed) does not have the same costs and overheads as as UK based industries, and can therefire destroy the home industry at a stroke, then dump whatever quality and price it chooses to manufacture on a captive marketplece. Problem is without strict import controls on the QUALITY of goods, there seems to be no way back. So yes, it is good that Brooks are still in Huddersfield (for now), but I wonder how many of its motors are still made there, and how many are employed compared to what there used to be. According to my "Brooks Book" (1971) 3000 employees produced 500,000 motors annually.

Phil

30/12/2014 17:15:58

Hi Russell,

Without wishing to get into an argument over motors, mechanical loading does not cause the slip, the slip is always there, as an unloaded motor would not rotate without slip! The rotor must be constantly slightly behind the rotating magnetic field playing catch up, and when the load is applied, the slip lengthens, and the torque produced increases up to the point where the magnetic field shears and the motor stalls. As you have said, the speed is synchronous, ie locked to the cycles of the alternating current, and is only marginally affected by loading, thus a motor rated at 1450 rpm will rotate at this speed unloaded.

As to all motors meeting certain standards, and reading Johns very interesting comments above, who checks? Does this include all the motors where the letters CE stamped on them actually stand for (they claim) China Export!

There is nothing mystical about 3 phase motors being vastly more efficient than single phase ones, it is more to do with the inneficiency of single phase motors. What I should have said in my analagy is that it is like comparing a single cylinder and a three cylinder engine of the same cubic capacity. If 3 phase wasn't more efficient, what would be the point of it, as it is generally three times as expensive to install? BTW the patent office will have nothing to do with anything claiming to be "over unity" as physics says it can't exist, so patents would be impossible.

Heat is a form of energy created by electricity in this case, and if a motor is running hot, some of the energy going into it is being wasted as heat rather that being converted into rotational power. A motor that runs hot is inneficient.....period! Yes, there are new high temp winding protection varnishes and resins, because some motors have to work in high ambient temperatures where they will not cool as effectively as if they were running in a cooler atmosphere, but running a motor hot does not make it more efficient. (no pedants need reply!)

Brooks owned by the Heathen Chinee! John, you have spoilt my Christmas

Phil

30/12/2014 14:41:50

Very good point Keith , bit like everything being rounded down to the cheapest outcome for the manufacturer! As to modern motors being more efficient, that is a very moot point to which the answer can only be, some are, but most aren't. You can buy very efficient motors from British or some European manufacturers (ABB Alstom etc) and they are expensive, but many of the italian made and especially the chinese made motors are noisy and run quite hot, both indicators of inneficiency, and also they use cheap bearings. It is a mistake to believe that because it is new it must be better. Have a look at this BTH motor about 3/4 of the way through Doubleboosts video https://www.youtube.com/watch?v=3Lkb9O8Y69U It may not be quite as electrically efficient as a modern good quality (expensive) motor, but it runs quiet and cool, and is continuosly rated, and almost certainly running on windings that are coming up for 80 years old! 3 phase BTW is approximately three times as efficient as single phase due to the 120 deg spacing of the cycle peaks. Easiest analogy I can think of is like comparing a single cylinder engine to a three cylinder!

Phil,

Thread: CovMac Lathes
27/12/2014 20:29:56

Hi Chris, when you say it blew a fuse, do you mean a fuse in the 13A plug?, not surprising really, you will need a seperate circuit wired back to your consumer unit and rated at 35 or 40 amps. Not a problem, as some modern electric showers draw this region of current and because of the clutch on the input shaft of the covmac, you will be starting the motor off load. There is a long way to go before you need to press the start button!

I am having a day off eating tomorrow!!

Happy Christmas!

Phil.

27/12/2014 20:05:39

Hi 9fingers, I would be interested to see the motor/ starter sort out! This is why I emphasised to Chris how important it was to get the original starter with the motor. It is an AEI Stayrite, and looks like it is the right one for the series parralell capacitor start. I have been in electrical engineering since 1967, and although these were not common, we did used to meet them on things like original Heidelberg printing presses which had been fitted where 3 phase was not available. There is nothing similar in my "Brooks" motor book, but I gather Chris marked the terminals when he disconnected the motor from the starter, so it should be a matter of servicing the starter and reconnecting as was. Capacitors in these installations are sometimes fitted in the starter itself, and switched in when needed. In the meantime I will have a rkae around my old paperwork and see if I can come up with any diagrams.

Phil

Thread: colchester bantam
26/12/2014 18:23:26

I would check the gears in the end case, it sounds like you have the wrong gears, or the wron order of gears on the banjo, this is a common problem, and is not at all obvious to a beginner what is wrong. Having said this my Colchester is a roundhead student! Have you got a bantam manual so you can set it up in standard gearing?

Phil

Thread: Where to buy conical washers.
18/12/2014 20:55:10

If you do a google search on M5 conical washers you will find a wide variety of suppliers and types of washers. Any industrial fastner stockist will have these, or know where to get them. We have one in Kingston upon Hull called F R Scott, who are very good, depends where you are in the country and what metal they need to be made of.

Phil.

Thread: Anvil find
08/12/2014 21:11:20
Posted by Ian S C on 08/12/2014 09:38:43:

If you can, mount it on a log, or old railway sleeper. It might end up looking like my onelaugh.

Ian S CAnvil , hammers, and a pair of Footprints

Blimey Ian, where did you get that massive box of matrches!

Thread: CovMac Lathes
07/12/2014 15:20:25

Hi Chris, well done to you, and a Merry Christmas to all! Don't worry about the chuck, it simply unscrews from the spindle anticlockwise, looking at the chuck face, top of the chuck goes towards the operator. If you get a large adjustable spanner and put it on one of the chuckjaws with the lathe in low gear and PULL! it should come off. Shock (hit) it with a piece of wood if you have to. If it doesnt move you can put a blowlamp onto the boss at the rear of the chuck, just to warm it, we are not talking serious heating, just enough to release the grip by getting the boss to expand slightly more than the spindle, then try again. remember the chuck comes tight against the flat face of the register, it does not get ever tighter on the thread. If you look at this pic again you can see the nose thread, with the register behind it, and the flat face that the chuck backplate tightens up against is visible just in front of the bronze bush. My chuck looked like it had been on for ever, but when I at last put an adjustable spanner on it, it unscrewed quite easily.

Phil (Bah! Humbug!)Whitley

Thread: Should you really get the biggest lathe possible?
06/12/2014 18:51:55
Posted by Roger Williams 2 on 06/12/2014 16:24:25:

Hello all, a friend of mine once remarked to me about buying things, who said, " ask youself 2 things , do you want it and can you afford it ". If the answers yes.......... As long as youve got room of course wink 2.

Ive got a big lathe that I admit I dont use as much as my smaller one, but I get pleasure from just owning and looking after the thing. I even get pleasure from being near my equipment, which I tnink is what its all about.

What really does piss me off looking at the lathes is what lovely machinery this country used to turn out, now we only make rules and regulations. Duty first, not safety first. Rant over. face 8

Absolutely right Roger, I will leave it at that, or I will start to rant too!

Phil

Thread: CovMac Lathes
05/12/2014 16:12:00

Hi All,

Well done the the shifting crew, always a stressfull job, but you breathe a big sigh of relief when its all safely done. My last big purchase was an Alba !A shaper, so only small really, and it came back about 30 miles on a two wheel trailer of indeterminate age and condition, Cheeks were nipping I can tell you!

Phil


Thread: Should you really get the biggest lathe possible?
05/12/2014 15:36:03

Bigger is better, but for modelmnaking (I am not a modelmaker, but I sometimes make small stuff!) I would say the biggest you wpuld ever need is the Colchester Student, beyond this the footprint is getting so big that you need much more space. I often put a smaller chuck in the student 3 jaw if I am working "small" ad of course men with lathes are often asked "can you lathe this down for me" Trying to do bigger work on a small machine can get a bit "hairy"!

Thread: What did you do today? (2014)
05/12/2014 14:53:49

I think that must be an old "Anvil" Tradition Bob, At my Anvil Arms in Wold Newton, East Yorkshire, also in the seventies, if you carried it into the bar and back you got a free pint, If you could carry it round the pub and put it back on the stand out the front, free beer all night! Couldn't be the same pub could it?

Phil Whitley,

Thread: CovMac Lathes
04/12/2014 18:28:55

Yes Brian, the hairhas been the bane of my life, very fine, very flammable with texture like 5 amp fusewire! I was called "hair bear" "Frizz/Fuzz" and when I started work "Bubbles" Now the boot is on the other foot, because a sizeable number of my mates are balding or bald, and at 62, I have dreadlocks down to my A*se and beyond ,which all go safely in a snood (well one leg of my daughters worn out tights actually) and down the back of my overalls. I look like one of the twins from Beano's "Lord Snooty"

Phil

04/12/2014 15:53:48

Hi Chris, Roger et al,

My first lathe was a DS&G 13Z much older than Rogers immaculate machine and with some front casting damage to handwheels and the SC gearbox. But it turned beautifully, and was a great machine to learn on. Yes, that is me in the picture, but that was in the 1970's............ Can uou tell where I ran out of green paint? Still in the same workshop, but the damp patch has been fixed now

Phil

Thread: Colchester Chipmaster wiring diagram
02/12/2014 11:25:47

HI Bob, there are three windins in a three phase motor, usually labelled A B and C. The winding connections are marked A1 and A2. B1 and B2 and C1 and C2. Connect A1 to B2, B1 to C2 and C1 to A2. You now have the motor connected in delta. Connect one phase to each of the three junctions and test. If the motor runs the wrong way reverse any two of the incoming supply leads. If this makes no sense send a pic of the motor connector, and any markings you can see on the motor leads, and the make of motor, and I will try to help.

Phil

UK

Thread: CovMac Lathes
29/11/2014 20:46:52

Don't worry Chris, It sounds a lot more complex than it actually is when you set it out stage by stage like I have done,

Don't wonder how to do it, get started and wonder how you did it!

Phil.

29/11/2014 20:34:27

Hi Chris, It's ok, I have calmed down a bit now, You and Neil have put your finger on why I wanted to convert my Covmac to Three phase, it is much more efficient, and therefore economical, but you also have to look at spending the money on extra power for the motor you have got, or spending it on a new motor at around £300, which buys a lot of electricity! I think I will go with Chris, and keep mine historically correct as well.

Phil

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