Here is a list of all the postings Les Jones 1 has made in our forums. Click on a thread name to jump to the thread.
|Thread: mitre saw use for roughing out/ vertical milling mild steel?|
If the saw blade was 80mm diameter then for the same cutting force the torque required would be 20 times as much as required for a 4mm diameter end mill. So if the saw blade was 2mm thick it would be like a 2mm depth of cut with a 4 mm end mill. I don't think I would attempt a 2mm depth of cut using a 4mm end mill on steel. To use the same motor you would need to gear it down by a ratio of 20:1 to increase the torque by 20:1
Edited By Les Jones 1 on 05/03/2021 15:49:42
|Thread: Battery Packaging Teaser|
When I was working I ordered some 2032 (Or similar cells.) though the companies logistics system. when I opened the package I found they had been packed in anti static bags. And as I expected they were all totally flat. A good example of a rule being made to protect things being use without applying common sense.
|Thread: Warco wm250 - wiring issue|
I agree with Oldiron that you should start your own thread. Also I seem to remember seeing information on three versions of the WM250 One uses a fixed speed single phase induction motor. Another uses a DC motor with a speed controller and yet another uses a three phase motor driven by a VFD. It would help it you tell us which version you have. Put that information in the first post of your new thread.
|Thread: Seized stopcock|
Before applying a lot of force I suggest buying or making a key for the outside stopcock so you can turn off the water in the event of something breaking.
|Thread: Chester Model B|
Does the motor run with no mechanical load on it ? (I.E the drive belt removed.) The larger value capacitor is the start capacitor. I think as it is a new motor you should Return it and get a replacement. Is it connected directly to the mains or via the internal lathe wiring ? I am surprised that Chester have supplied a Clarke motor. Is the connection information supplied with the motor identical to the first post of this thread ? If you want to do some investigation of the fault this is what I suggest. Remove the two link bars. Measure the resistance between U1 and U2. This will be the main winding and I would expect a resistance of less than 10 ohms. Measure the resistance between W1 and W2. This will be the auxiliary winding and it's resistance will be greater than the main winding. (But probably less than 20 ohms.) Measure the resistance between V1 an V2. This is the contacts on the centrifugal switch which should be closed when the motor is stopped and the reading should be very close to zero ohms. Report the readings and we can tell what is probably wrong with the motor. (Not that it really matters as you will have to return it as faulty.)
Edited By Les Jones 1 on 13/02/2021 18:05:25
|Thread: Reversing Motor|
You would be looking to see if there are any wires or links on the back of the board. For example terminal K only has a white wire from the run capacitor so unless there is something is connected to K on the underside of the board the run capacitor is not serving any purpose. IF Noel's suspicion that the centrifugal switch has changeover contacts is correct and the NO contact is connected to terminal K then the run capacitor would be connected in series with the run winding when the motor was up to speed. (Which is how it should be in circuit when the motor is up to speed.) I have only ever seen centrifugal switches which connect the start capacitor in parallel with the run capacitor until the motor is up to speed. Most motor are easy to take apart. There is normally 4 threaded rods holding the end plates together. There may also be bearing retainer plates that are held in place with two screws close to the bearing housings. The bearing will probably remain on the shaft when an end plate is removed. Take care to note the position of any springy washers that might be in the bearing housing.
You can probably use the NVR switch that you have. Post some pictures of it so I can check if one end of the coil can be accessed. If it can I will post a diagram of how to connect it.
That switch can be used both for single phase or three phase. It does not even need any change made to the links between terminals. The only thing that I would recommend is using a contactor with thermal overloads with start and stop buttons. In that case the lower set of contacts on the reversing switch could be connected in series with the coil on the contactor. This would prevent switching directly between forward and reverse as if it was attempted the contactor would drop out as the reversing switch passed through the middle position. Using the stop and start buttons would also increase the life of the reversing switch. I cheaper alternative to a proper contactor would be an NVR switch that had the option of breaking the feed to the maintainer coil.
Well done Emgee in giving the solution to the problem in his post at 18:37 on 04/02/21
If the wire (Yellow or blue.) that had a short to earth was connected to terminal A (which is connected to neutral.) The motor would run without tripping an MCB (Or blowing a fuse) But it may trip an RCD.. This depends on voltage drop across the neutral conductor from the RCD. (I will not try to explain this in detail as it involves understanding exactly how RCDs work.) If the wire that had a short to earth was connected to Z then live would be connected to earth via the start capacitor which could trip an MCB (Or blow a fuse). If it only had leakage to earth rather than a dead short it would still trip the RCD.
This is my revised diagram.
I have no solid conclusions but here are some comments.
Keith, Can you check the insulation between the auxiliary winding (Yellow and blue wires) using an insulation tester / megger and earth. (It would be a good idea to test the insulation between the rest of the wiring and earth at the same time.)
I would be interested to here comments from Emgee and/or John Fletcher as they may have spotted something I have missed.
Edited By Les Jones 1 on 07/02/2021 11:09:34
Noel, I have never seen a centrifugal switch with change over contacts. I have only ever seen it wired to connect the start capacitor in parallel with the run capacitor during starting. Also I can see no problem with the diagram of the reversing switch that Nick has drawn in his post at 10:28 on the 5th. The top two contact sets are wired to reverse the polarity of the auxiliary winding and the bottom set cuts of the power to the motor in the middle stop position.
Edited By Les Jones 1 on 06/02/2021 17:51:06
I am assuming the wire that you call grey is the one marked black on the diagram. (And was connected to terminal A) Am I correct ?
Above is the way I think it is connected. but it looks like the marking for the start an run capacitors are the wrong way round. Can you follow the wires from the terminals to the capacitors and read the values of the capacitors so we know the values tied to the start and run capacitors as marked on the diagram from the motor.
If you swapped yellow and blue over as indicated on the motor diagram and it tripped the breaker then that information must be wrong. Am I correct in assuming that the motor ran with those wires in the original position ?
The first reply to your post has a link to the instructions to post pictures on the forum,
Do you have a multimeter to work out the truth table for the switch and to identify the main an auxiliary windings on the motor ? Post as much information as you have on the switch and motor and pictures of the connection box on the motor and the switch showing any number / letter marking on the switch. Is the switch a two position or three position switch ?
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