Member postings for john fletcher 1

As Martin above say most inverters seem to be manufactured to be fitted inside a cabinet. My inverters are old type pre used and they were intended to be mounted within a cabinet. I bought 3 alarm boxes at a car boot sale and mounted the inverters in them. I drilled a lot of holes in the bottom and cut a large square shape hole in the top, on which I covered with fine steel mesh. I made 4 spacers about 20mm long, cut and shaped a piece of sheet steel (slopped all four sides) about 20mm all round bigger than the top of the box. I drilled 4 holes in each corner through both the new" LID" and the top of the box, so that when I screwed the lot together it looks a bit like a Chinese pagoda. Cooling air can pass in from the bottom over the inverter, out through the mesh. the pagoda "LID" top keeps out any bits of swarf which might pass through the mesh. All that was at least 20 years ago and I've not had any problems. Incidentally remote control boxes are easy to make, as all the voltages are low 12 or 24.John

I don't think 4mm banana plug will carry 20 amps for long, nor do I think they can accommodate thick wire either. Speak cable is very supple and comes in several sizes, so I think that's the route to go. The only reservation is will the insulation stand the heat. Its not costly for a small amount, so give it a try. I have some on my big battery charger, with an identification tape on the + lead both ends, its been on years. ted

The start circuit is open circuit an Neil says, and the weak point is the centrifugal switch. Capacitors are pretty reliable, never the less the do fail. If you have an old fluorescent light capacitor you could try a substitution initially. You could get your friendly electrician with his 500 DC insulation tester to care out a rudimentary test on your capacitor before removing the motor from the lathe.If you do have to take the motor to pieces you will find the switch is at the no drive end, so its a complete strip down. Mark both end of the motor using a scriber and steel rule two lines one end and one the other. These lines are to help with alignment when you re assemble the motor. with a bit of care you might be able to take out the through bolts and just ease out the drive end shield and rotor. The centrifugal switch actuating bits are attached to the rotor, they fly out due to centrifugal force against spring tension as the rotor speeds up. The assembly should be free to move, don't oil them. You will see the actual switch which is attached to the end shield, it might not be obvious how the thing works, the contacts might need a clean up with a bit of fine wet & dry,not too vigorous. As your motor is quite old so be careful with the wire insulation. It might be a good idea to get an electrician to give the motor an insulation test. When replacing the motor ensure you a have good sound earth, to the lathe and motor.Ted

A KW is the same no matter where it comes from. 10 X 100 watt bulbs = 1 KW. Some fan heaters maybe quieter running but 2KW is the same. 22 years ago I responded to an advert in the local evening paper an Ebac dehumidifier for sale and it been running in my wooden workshop every winter since. They switch on and off as and when necessary and don't use much energy. I have a recording wattmeter and have checked it quite a few times and I think it excellent and would recommend it/them to anyone. I don't need to cover up the lathe or mill at the end of a working day. It is important to ensure that the building is well sealed up otherwise you are trying to improve the world. Before buying the manufactured dehumidifier, I made one from an old fridge using the ice box and an ex computer fan, it worked but was bulky. Several years ago there was an article in ME regarding making your own dehumidifier. Those people with damp houses should ventilate better especially bathrooms and buy a dehumidifier.Ted

Obtain an old micro wave transformer remove the high voltage. Wind on a new secondary, not a long job for 12 or 13 volts, secure with air drying varnish. Be careful when passing the copper wire through the core, I stick masking tape around any sharp edges. Connect the new winding ends to a bridge rectifier and to an electrolytic capacitor ( I use 1000 micro farad per amp ) and you have useful power supply for very little cost . It should mounted in ventilated enclosure and EARTHED.

Now that the motor windings are configured in Delta why not connect two of the three connection to live and neutral. Then connect one of the capacitor leads to the vacant terminal and the second lead to either live or neutral. I can't exactly remember the capacitor value but think it is around 4 micro farads at 400 volts. I have done this arrangement for several friends and it works, no over heating or other problems. Ex fluorescent caps are ideal. You may have to play around a bit with cap values to get things quite right. I'm sure some one here ,will remember the correct cap values, its quite a well known idea. Forget running on an inverter especially at slow speeds. The motor will get hot as it is on load and rotating slowly.Ted

Try Squires 100 London Rd Bognor Regis West Sussex PO22 1 DD. 01243 842424, they also have leds.Ted

The dust and muck needs to be sucked out not blown in and compressed air often contains a lot of water. As Phil says put the motor in a warm place to dry out /remove any dampness. If you know an electrician get him to carry out an insulation test on the windings. I'm assuming its a three phase motor, have a three phase supply or are you going to invest in an inverter ? Motors that age often had their windings insulated with natural resins so if the insulation resistance is low don't despair, your local rewind shop can dismantle the motor and re dip the stator for you. Hopefully not necessary. Tell us more about the Startrite box on the wall, certainly take it home. I'm following your task with interest.Ted

I'm not sure what size of motor you need but there are plenty on the market and an ad here or on Home Work page will I think get some response. Many motors have provision for reconnecting to Delta within the terminal box, usually there is a label under the terminal box lid explaining what to do. Locating the STAR point is not so difficult either, but it does need the motor to be dismantled. Scratch mark the stator and end shields so that it is easy to reassemble, two marks one end one mark the other. Be careful when with drawing the rotor, not to scratch the varnish off the copper windings. Look at the stator winding ends and you should find a lump, not a big one but a lump never the less. That is the STAR point where the three wires are connected together, they need separating and extending so that all three will extend into the terminal box, together with the other three,6 in all. Make sure that you insulate the new connections very well. Next you have to get the Delta connections correct, for this you will need some form of continuity tester, a multi meter, battery and bulb or battery and buzzer. There are three separate circuits, for every circuit there must be a one end and a two end of the winding. Identify and label all three using the meter and some coloured tape or masking tape with writing on. The original ends will all be the two ends, mark them U2, V2, and W2.Now connect together U1 to W2,W1 to V2 and V1 to U2 using a block connector. Job done. Sorry I don't know how to included a diagram. Regarding an inverter, there are plenty of used one advertised and I've never heard of anyone being ripped off. One of mine is more than 25 years old and it wasn't new at the time. Making a remote control box is easy as well. The control circuit is low voltage so cheap pushed and other switches are available from hobby shops. I suggest you do include a relay to give isolation from the main in the event of mains or other supply failure. give it a go, sorry about the protracted write up.Ted

Around where I live we can buy King span rejects, which consists of two sheets of profiled plastic coated steel with 75 or 100mm insulation foam between. The inner is white and outer often green, but can be painted a different colour later. My friend made a concrete base with all the usual polystyrene and damp proofing, then laid marine quality ply on top, then erected the walls. The shed is so light and warm, I think it only needs a couple of light bulbs to keep it warm and damp proof. Farmers use the same material for animal building roofs. The sheet are 4 metres long and a damaged on one end where some one has been careless when handling with a forklift, that can be cut away using angle grinder with a thin disc. I've had my workshop for more that 25 years but if I was to start again it would be Kingspan. For £30 the owner delivers and if you take a complete pack its even cheaper. I notice an advert in Saturday Yorkshire post for similar material. Ted

I had a 1934 Austin 7 in the 1950's and did allsorts of mods to it.ongoing, several of my work mates had them as well. the wind screen wiper was a pain so I mounted a steel container under the bonnet fitted with I think a non return valve. We lived in Lincoln and going up hill with no wipers was dangerous. I modified the distributer to give automatic advance and retard. I fitted new bearings to the engine plus I think cord piston rings. It was a little flyer. Being an electrician I was able to fix the third brush dynamo and starter motor Ok also fixed the dip solenoids in the head lights. I can remember fixing a puncture on the road side. You have brought back memories, I've just got out my 1957 AA book. I think mine had a two bearing crank and my brother in law had a Ruby wit a three bearing job..I could go on .Ted

Regarding the blown 60 Watt lamp failing and then the main fuse blowing. Whilst this is not a common occurrence it does happen. As the element/filament fails it shorts across the pair of leads within the glass envelope forming a short circuit. The old type of wire mains fuse ages, not all premises have cartridge fuses even today. I will explain, the piece of wire, warms,expands, warms again, cools etc and gradually its cross connectional area reduces and then its fails, often at the most inconvenient time. When considering the size of cable for a workshop installation don't forget that you won't be using all machinery at the same time so total load is different to load in use. Diversity !

An interesting aside. 6 students rented a house, on arrival one switched on the hall light, it didn't work, another tried the living room it didn't work either. They tried them all of the lights and non worked, this was on a Saturday evening, so they used their phone to call the supply company. When the man arrive he checked the mains and all was well and at first he was a bit confused. The previous students had collected a lot of failed bulbs and fitted them to all lamp holders before departure. Total cost £75 .

I am not familiar with a Selects motor, but I have had a look via Google and it would appear to be a capacitor start motor. Perhaps you could have a look inside to see if there is a centrifugal switch which would confirm that it is a capacitor start. You haven't published any details regarding the wattage of the motor which might give a clue as to the micro farad capacity of the capacitor. The actual micro farad rating is not precise some thing in the region of 60/70 could be OK as they are often plus / minus 20% anyway. The working voltage should be at least 260 and they special AC electrolytic motor start type. I notice that Selecta list a permanent capacitor type motor as well with a 500 micro farad capacitor. If you have a motor rewind shop near by they will know the value and sell you one. It can be mounted close by in an earthed metal box.Ted

For the control circuit you can use multi cored screened cable from ex computers leads. As the above states all the switches can be obtained from Maplin or any other electronic shop/ The pot needs to be a linear type NOT volume control there log. Some inverter controls are 5 K ohm, I notice the above says 10 Ohm I'm sure that is a mistake it will be 10 K ohm. 3 phase motors are around and it not difficult to alter the connection and the worst thing you will do is blow a fuse. We read that inverters need a special motor design for them, well that might be so in industry but for us hobby type we won't notice the difference. I have 3 inverters all 2nd hand, three 3 phase motors and they were pre owned. I think all the technical details of all the makes of inverters are on the net. Give it a go, but please ensure that all the metal work included the motor are adequately earthed.Ted

Before buying an expensive package, consider buying separate items. Motors are readily available, but check that it is the type with six terminals, other wise is can be a bit tricky to locate the star point which requires a motor to be dismantled( motor rewind people will fix it at a price, easy if you know how). Inverters are available on the net from the Far East and ebay at a good price and there appears to be lots of helpers around if you get stuck with the set up. Should you need a remote control package, they are easy to make up and the bits area available from Maplins.Three phase motors are inherently smoother in operation 12 pulses a rev as apposed to 4. Also 3 phase motors are simpler than single phase, no switch, capacitor or start winding to go wrong. Regarding the belts have a trip to your local bearing factors, they will have a range of belts suitable for Myford lathes and I have found half the price of the lathe dealers.Ted

Never seen a cap start/ cap run fitted from new, on a Myford lathe, very unusual. Usually just cap start is sufficient, after all they start on next to no load. On cap start/cap run motors, the centrifugal switch is used in BOTH directions, it open circuits the larger of the two caps (60 or 70 Micro farads depending some what on size of motor) once the motor is up to speed. Then the motor continues to run on the paper type run cap only. Cap start/cap run motors, usually there are TWO cylindrical (tubular) objects attached to the motor, one larger than the other. The larger is a special AC electrolytic type, which is only in circuit for a brief period in time(short time rated) when the motor starts up. The smaller is a paper type, continuously rated and is in series with the run winding, which of course is in use all the time the motor is actually running. An electrician using his 500volt DC megger will carry out a rudimentary test on the smaller one for you. An ex fluorescent light fitting power factor correction capacitor will be OK as a temporary measure for a quarter horse motor. After all of the above, most of which is irrelevant, I still say have a good look at the reversing switch and, using a Myford be careful regarding running the chuck off.Ted

I suggest you phone Les. It can't be the centrifugal switch as it is used in both directions, so are the start and run windings, so that almost says the motor is OK. More like the dreaded "Dewhirst" reversing switch burnt contacts, they are just not man enough to be used as an ON/OFF. When you have sorted the Dewhirst get your self a proper motor starter with green/red buttons, with No Volt release. John/Ted

Over the past twenty years I have had reason to remove pulleys from several Myford super seven lathes motors and all have fixed by grub screws, not a key in sight. Once the grub screw is removed, all that is needed is a bit of careful persuasion using two pieces of flat steel or similar.Ted

I,m pretty sure its a misalignment problem. These motors are turned out like shelling peas, they were cheap and cheerful. The stators are wound and the rotors are just popped in. When dismantling any motor its is important to mark the stator and end cover so that correct alignment is established, otherwise binding takes place.(Two parallel scriber scratch marks one end, stator to end cover, and single scratch mark stator to end cover the other end) I suggest you slacken off all 4 bolt and rotate the rotor by hand and tighten 2 bolts diagonally a bit at time. You may find that a tap here and there with a soft mallet will move things so that the rotor moves freely.Ted

Neil, I like your idea about using the gears from an angle grinder for use on a shunter. I thought about using them as a horizontal drive for my milling machine, but just changed my mine after reading about your idea. I had two scrap ones given me last week.Ted