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: check valves|
If you use a brass bodied fitting to make a non return valve with a ball bearing and a spring, the magic trick is to seat the ball into the brass by giving it a sharp tap with a hammer and a flat ended punch. I have made non return valves for compressors using this method, and they don't leak!
|Thread: Barking Dogs|
Ady1, the road is not fine! unless it has a speed limit of 40mph or more!! Anywhere where the speed limit is under 40mph is included in the act, and means you must pick up from the road as well!
My local town council, of which my wife is a member, recently put out a survey to every household in the town, asking what they wanted the town council to concentrate on to improve the towns amenities. Top of the list was to do something about derelict buildings in the town, all owned by tesco, and bought to prevent other supermarkets opening in competition to them. Second on the list was to deal effectively with dog fouling. It is dangerous, and can cause poisoning from the Toxicara it contains which cases blindness and can result in peripheral amputation due to gangrene. In public parks where children play the chances of them coming into contact with this filth is very high. So you see it is not loony councils who have come up with the idea, it is actually what the people want. Dogs are carnivores, horses are herbivores, and their droppings are very different. You Dont see many people rushing out to put dog crap on their roses for a very good reason! dog crap is toxic! Horse crap is not. Funnily enough, my cousins wife breeds collies under the Wicani name, and has changed her dogs onto an all raw meat diet, completely cutting out biscuit and commercial processed dog foods, and has seen a massive increase in the health of the dogs, and the numbers of puppies in a litter. Also cleaning the kennels is a much more pleasant job as the foul smell usually associated with dog crap has all but dissapeared. Perhaps feeding them junk food diets has something to do with the proble?
|Thread: Electric motor help needed|
"No the regs won't let an untrained tech do a PAT test, unless the tester is automated and the test procedure is set up by someone competent to do so. Quite right too."
Sorry Simon, but PAT is a complete farce, an industry created by introduction of legislation from zero need, no evidence that it has saved one single electrical accident as electrical accidents in the home and workplace have been falling for years. If this hacksaw is in a home workshop with only the owner using it there is no requirement in the Regs for it to be tested, and the "competent person could well be an ex Macdonalds employee who has done the two day PAT course at a local college, and most of the first day is Elf and safety. During the days of the "back to work" grant, my local dole office was offering a package consisting of a pair of overalls, a pair of safety shoes, a basic PAT machine, and a two day training course to anyone! No requirement for any previous experience whatever. That is how competent your local PAT man may actually be!
|Thread: Repairing a 4 jaw chuck.|
Excellent repair Brian, and a damned good idea!¬ Must file that away for future use!
|Thread: Miss Britain III|
Like it! the real one is in the foyer of the Maritime museum in London. Having a Napier engine put it on my must see list on a trip to 'T smoke a couple of years ago.
|Thread: Electric motor help needed|
Just to add to my last post, usually faults on single phase motors are more common on the start winding than the run, If the motor runs up to speed, and you can hear the centrifugal switch open, then the start winding is out of circuit. If the problem is a shorted winding it need not be down to earth so will not show up with an ammeter, and is difficult to trace unless you know what the resistance of the windings is supposed to be. I still think it is the trip itself that is faulty, I have known many fail, far more than motors in fact.
the only way to effectively test this motor insulation is with a megger tester, as has been said above. an ammeter in the earth wire will work, and is perfectly safe as long as it is the old fashioned type of ammeter which has a solid coil of copper wire between its terminals anyway, so will not break earth continuity. It must be 240v rated though, NOT a car type!!! If there is sufficient current flowing to trip the internal trip, which is current operated, not thermal, then a clip on ammeter on the eart w. ire would also work, as there should be no current at all in the earth wire. My feeling is that if this motor was down to earth, it would be blowing the fuse in the plug, and the most likely cause is that the trip itself is faulty. these motors are fairly bulletproof, I have one on a pressure pump that is identical. see if you can source a replacement trip and fit it. If not, check the full load amps on the motor plate, fit a fuse just larger than this rating, and take the trip out and connect the trip cables together, and retest. If it runs reliably without overheating or blowing the fuse then you are good to go. If this saw has been used to the capacity of the motor for a long time, it will have cooked the trip. The problem with buying a new motor is that it will be chinese (really crap) or italian (fairly crap) or VERY expensive. Go with what you have till it is proven to be a winding fault.
|Thread: Brain Teaser|
Tube is a hollow structural member of any shape or section.. Because it is used in construction, its most important dimensions are the external dimension, and the wall thickness as an indicator of structural strength.
Pipe is used to convey liquids or gasses.and because of this use, the only important dimension is the internal size, which gives an indication of the carrying capacity of the pipe, and the wall thickness, which gives and indication of the internal pressure the pipe will withstand.
Whilst pipe and tube are in a sense interchangeable terms in conversational English, in engineering the use of the term"pipe" for a hollow structural member, and tube for something that carries a liquid or gas, used to result in a thick ear for the errant trainee or apprentice.
Wanders off mumbling under breath about falling standards and the kids of today etc etc...................................
|Thread: Appraising an electric motor|
Thanks for the link Neil, it is very good, and needs to be read carefully!
`As I have explained, over greasing causes bearing failure by entraining dust back into the bearing. The assertion that having too much grease in a bearing causes failure of itself is a myth, or at very least a misunderstanding. Lubricant is there to prevent metal to metal contact, if there is insufficient, the bearing will fail.
"Even my ancient Machinery's handbook gives the designed temperature rises for different types of motor. Open frame general purpose motors have a rise of 40C over ambient while totally enclosed motors with type B insulation are designed to cope with a temperature RISE of 105 C above ambient.
The main differences are in the insulation, but it is quite acceptable to run a TEFC motor so hot you can't put your hand on it."
This may be so, but rate of rise and operating temperature drastically affects service life, see http://ecmweb.com/content/hot-issue-motor-temperature-ratings, for an explanation of this.
It used to be common practice to size a motor 25% more powerful than was actually needed in order to give a good reliability factor. For reasons of economy, today, motors are generally just powerful enough to do the job and no more, hence higher running temperatures. There is no electrical or mechanical advantage whatever at running at these higher temperatures, it just means the motor can cope with more overload and thermal shock before the insulation breaks down, but it will shorten service life, as the margin between running temperature and failure of insulation temperature has been narrowed, and it will also cook the grease in the bearings and allow it to melt and run out to some extent, which again will cause bearing failure, and when the bearings start to stiffen up, the motor goes into overheat very quickly, and burns out.
Motors fitted with grease nipples and relief plugs run with their bearings absolutely full of grease, and when greased correctly, have indefinite bearing life (30+ years as in my post above). Modern motors run hot and with the sealed for life type bearing, motor and bearing failure is commonplace. They are literally, disposable motors. A bearing failure will take out the winding insulation in a very short time.
So it may be "acceptable" to run a motor so hot you can't bear your hand on it, just don't expect it to last very long!
Ian SC, used to see ring oiled motors on "original Heidelberg" printing presses we used to service, very quiet and very long lived as long as they get an oil change regularly!
Hi Steve, as usual the answer is, it depends! This is going to be complex! If you are putting a motor into a position where it will be in service for a long time. It would be best to strip it, wash out and repack the bearings. Here I will be controversial, and tell you to pack the bearing full of grease on both sides, and refit it. Others will insist that it is incorrect, and will say that it should only be one third full, or half full, one side only etc etc. Tell me then how a bearing stays one third full when it is fed by a grease nipple? Many will quote what they have read in bearing manuals, and that I also take with a huge pinch of salt. The bearings we buy today are not sealed, they are shielded, and dust can still get into them, you can also pop the shields off with a jewelers screwdriver, and if you do, you will be horrified how little grease is in them, they are, in fact "sealed for (a short) life". as I have said above, I have washed out and repacked thirty odd year old bearings and refitted them to many many motors because they were still in good condition. So, if the shields do not seal the bearing, why are they there? The only conclusion I can come to is to prevent any more grease being added and thus shorten the life of the bearing, and increase sales. I have changed hundreds of car wheel bearings, but the cause of failure is always that the external seals have broken down and allowed water and dirt into the bearing. If a bearing is kept clean, supplied with sufficient clean lubricant, and not overheated it should last indefinitely, but modern bearings do not. From this I can only assume that they are made from inferior materials, which I doubt, or that they are incorrectly lubricated, which can occasionally mean too much but mostly by far, too little.
When you rebuild a motor of the Brook Type with grease nipples, you will see that the grease nipple is at the top of the motor, and underneath the motor, somewhere on the lower portion of the end shell is a grease relief plug. To lubricate correctly, you remove the grease relief plug, (which is what our miller did not do!) check the relief hole is clear with a piece of wire, then put a grease gun on the nipple, and add grease to the bearing until it (just) starts to come out of the relief hole, then stop and refit the plug in the relief hole. The bearing is now completely full of grease (which gives the lie to those who say this should never happen!) If a motor is in use 8 hours per day this process was normally carried out weekly, with the motor stopped! If you grease a motor while it is running the grease will tend to ooze into the motor as there is usually no seal to stop this. By doing this you are effectively changing the lubricant constantly and flushing out any debris in the bearing.
Different motors used different methods, some had grease cups which were filled and given a certain number of turns for a set period of time, (1/2 turn per day, refill weekly) usually all the information needed being marked on the motor plate.
In today's modern world of course, we have advanced so far that we no longer need old fashioned things from yesteryear like grease nipples, so today's motors last till the tiny amount of grease polymerises or gets some dust in it, and then the extra load overheats the motor, the grease turns to tar and the motor burns out, and we throw it away and replace it, which is exactly what the manufacturers intended.
As you have spotted Steve, the grease has nowhere to go unless there is a relief plug, so it will force its way past the unsealed shaft and into the motor, and you will also see some exit at the shaft end around the shaft, as soon as you see this STOP PUMPING! If grease has been allowed to escape inside a motor which is not totally enclosed then it will pick up dust and some of that dusty grease will be dragged back into the bearing by the rotation of the shaft, and dust laden grease is like grinding paste. Incidentally, later motors sometimes had an unplugged relief hole, and the same rules apply. It is also sometimes possible to look through vents into the motor to check that grease is not coming out round the shaft. On your Myford, or similar, if there is sufficient grease in the bearing, and assuming you use it fairly often, a couple of pumps four times a year is sufficient. You have started from the right place, because you were in doubt, so you stripped, cleaned and repacked the bearings, now you only need to grease occasionally. I hope I haven't bored you to death!
I don't think they are designed to run hotter, and I cannot think of any advantage electrically speaking, of doing this. They run hotter because the cases are now usually thin lightweight aluminium, finned to reduce heat. If you come up with a higher temperature varnish, you can use less metal in the case, which saves money. Most modern TEFC motors have a pathetic plastic paddle of a fan hiding behind the cover, so the cooling is just adequate, but usually the first time they overheat, they burn out.Heat always damages insulation and varnishes, and if the insulation on this motor is good, there is no advantage in rewinding it. A simple megger test would prove it. The weight of cast iron, which is in intimate contact with the stator laminations acts as a huge heatsink, I can't actually tell from the pic, but this looks like a drip proof type, which has an internal fan and bottom inlets and outlets for air. Always worth making sure they are clean and blowing through with the air line, and a couple of pumps of grease for the bearings, which will also last a lifetime, as you CAN grease them! Ambient temperature in factories are a lot lower than they used to be thanks to COSH/HSE. The old Brooks worked everywhere from freezers to foundries. They did occasionally burn out, usually when something went drastically wrong with the machine. I remember being sent on the "shop bike" with a box of tools and a megger to look at the mixer motor in the local animal feed (provendor) mill. 140Hp star delta Brook, and it was red hot, and burned out. Had to take the roof off the motor room, and the roof off the factory, hire a crane and lift it out. Brooks sent a low loader to collect it on the day it happened (Friday), it was rewound over the weekend, and returned on the Monday and reinstalled. The cause of the burnout was the chap who was greasing the motor DAILY! It was half full of grease, and a drip proof which meant that dust drawn in to the motor was mixing with the grease, reducing the cooling, and being drawn back into the bearings which were gradually seizing up. The motor soldiered on against this extra load, but it was not enough to trip the overloads, just enough to slow cook the winding. Some "re education" was done at the factory and it never happened again. We also suspected that they had tweaked the overloads a bit, they weren't supposed to touch electrics, but you know what millers are!
|Thread: Useless light bulbs.|
GE have announced that they are to cease manufacture of CFL lamps, and we are now beginning to see the less common types like the two pin halogen and the GU10 halogen begin to appear in led form at reasonable prices. LED saves a fortune in electricity and bulb replacements, the fitting in our kitchen has 5 GU10 bulbs and needed replacements every two to three weeks. Bought 5 led replacements at Lidl for £3-50 each, fitted them and forgot them, also much better light.
|Thread: Appraising an electric motor|
That looks to me like a Brook Empress motor with the external centrifugal switch. You will have to buy a very expensive motor indeed to buy better quality than that. The assertion that modern motors are better in any way is an absolute myth. These were designed and built to go into industrial situations powering machinery for at least eight hours a day, and last indefinitely, and I can assure you that many of them did!. One of the first jobs I worked on as an apprentice in 1968 was reconditioning Brook motors which had been removed from a factory built in 1932. All original, stripped cleaned re-lubed, and back into service. Modern Chinese motors are awful rubbish, and very inefficient and noisy to boot. Italian ones aren't much better and that covers the majority of motors made in Europe. The Industrial stuff made by Alstom and the like is very good, very efficient and very expensive. but will last the course. Brook still make motors in Huddersfield, but are now Chinese owned. I have no idea whatever why people pay £200 + for a "Myford" motor as there is no such animal. Motor fittings and bases have been standardised for donkeys years and getting a motor to fit should not be a problem. Whenever I need one, I go to the local rewind shop, and buy a recon one! If you need a 2hp single phase motor, you will not get a better one than that!
|Thread: Bridgeport Circuit Questions|
Hi Norm, Not familiar with transwaves, but gathered afterwards that the third phase is generated by the motor itself. then checked in my Brooks book, and it all came flooding back! Yes, it is usually something simple! I am lucky, I have real three phase! Glad you solved it!
OK, swift rethink, can't actually make out the circuit diagram, but if there is a 110v control circuit you will have to test for this voltage to earthy at the start button. If it is not there, that is the problem. Is there a neutral in the cabinet, or is it just 3 phase?
In the picture of your cabinet, it appears that the screw in fuse (if that is what it is) on the extreme left of the cabinet is blown, as its indicator is not visible in the window. . The output from the3 phase transwave should be 220v on each phase when tested between phase and ground (earth). Check through the overloads with a multimeter (POWER OFF!) to confirm continuity. It is possible that the missing phase is one of the phases that operates the starter coils in the contactors, so the motor runs up when you manually close the contactor but will not energise when you press the start button. On pure three phase systems, the Coil on the contactors is rated at 440v and operates between two phases, if either of these phases is missing the start button will not work. Is there a button marked "reset" or possibly "STOP" (Reset). if there is push this and try again!
|Thread: Oil Rings for Norman T300 Wanted|
Hi, do you mean oil seals or O rings, if you post some pics up, I am sure someone can help you. Also state where you are in the country, because there are many suppliers who have kept old stock and parts for many years, one such being Oliver Lodge and Co in Hull who had stock of an old leather oil seals for a 1950's compressor I rebuilt, but no use to you if you are in Plymouth!
|Thread: surface rust on lathe ways|
Hi all, pgk pgk, remember, you have to allow the air that is going up the flue into the building, as if you don't what happens is exactly what you have experienced. Rather than create a draft across your shop, you need an air pipe at least the same size as the flue to take air to as near to the stove inlet as possible. I have heard a rule of thumb that stated that a "brightly burning fire" in a domestic size open fireplace draws 24 cu ft a minute of air up the flue. If your "shed" is really a shed with a wooden floor, cut a hole either side of the stove and put hit and miss vents on so you can close it off when the fire is not lit.
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