By continuing to use this site, you agree to our use of cookies. Find out more

Member postings for Les Jones 1

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?
05/03/2021 15:47:37

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
I agree with the other replies that the answer is NO.

Les.

Edited By Les Jones 1 on 05/03/2021 15:49:42

Thread: Battery Packaging Teaser
24/02/2021 11:08:14

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.

Les.

Thread: Warco wm250 - wiring issue
21/02/2021 18:03:30

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.

Les.

Thread: Seized stopcock
13/02/2021 18:47:55

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.

Les.

Thread: Chester Model B
13/02/2021 18:03:10

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.)

Les.

Edited By Les Jones 1 on 13/02/2021 18:05:25

Thread: Reversing Motor
10/02/2021 09:33:06

Hi Noel,
I can see that the motor in your pictures has a changeover centrifugal switch but I don't understand how you KNOW that Keith's motor has this type of centrifugal switch. To reduce the number of conductors required between the motor and reversing switch I propose to swap over the blue and purple wires rather than the blue and yellow wires. (This is assuming yellow is connected to Z.) This is because the points A and AZ are already available at the reversing switch. If it is a changeover centrifugal switch I think the purple wire is the common of the changeover switch and the NO contact is connected to terminal K. BEFORE suggesting this I want to be SURE that there is no hidden connection between the main winding and auxiliary winding / capacitors / centrifugal switch.

Les.

09/02/2021 22:29:21

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.

Les.

09/02/2021 20:12:41

Hi Keith,
The NVR switch in the picture is not suitable for the way I suggested wring it. This is because both ends of the coil are directly connected to the output. In this NVR switch on ebay there is a picture showing that one end of the coil winding is brought out to a separate terminal. (Marked A1) Any NVR which with one end of the coil brought out to it's own terminal can be used. It looks like there is no direct connection between K and AZ. The way your meter behaved is what I would expect when it is effectively connected to a capacitor. (In this case the run capacitor..I think the only way to confirm that the centrifugal switch is not the changeover type that Noel suspects is to partly dismantle the motor.

Les.

09/02/2021 11:46:41

Hi Keith,
Noel makes a good point about terminal K being connected to the NO contact of a changeover centrifugal switch. (Although I have never seen one that method would work.) I think it would be a good idea to dismantle the motor to see if there are two or three wires going to the centrifugal switch. You could also check if there was anything connected to the terminals on the underside of the terminal board.

Les.

08/02/2021 14:54:58

Keith,
Now all the wires are re connected to the terminals can you measure the resistance between terminal K and terminal AZ. (You will initially get a lowish reading (Due to the capacitors.) but it is the steady reading I am interested in. This is to try to understand why the run capacitor did not seem to be connected and also see if the number of conductors between the motor and the reversing switch can be reduced from 5 (+ earth) to 4 (+earth).

Les.

08/02/2021 13:13:59

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.

Les.

08/02/2021 09:29:55

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

Les.

07/02/2021 13:19:59

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.
Was it an MCB or the RCD that tripped out ?

Les.

07/02/2021 11:40:40

This is my revised diagram.

070221.jpgLes.

07/02/2021 11:01:55

I have no solid conclusions but here are some comments.
As a result of some further tests after I posted what I thought was the way it was wired at 9:27 on the 6th my diagram is wrong. The centrifugal switch is NOT connected between K and S which I had assumed as a result of the zero ohms reading in the post at 23:12 on the 5th and the fact that it would seem to connect the start and run capacitors in parallel. The post at 16:12 on the 6th now shows no continuity between K and S and Keith has since proved that what I thought MIGHT be a thermal cut out (Even though it not in the right place to remove the supply to both windings.) is in fact the centrifugal switch. I seems that there is nothing connected to K other than one wire from the run capacitor. When the motor ran with the original way the auxiliary winding (Yellow and blue wires) was connected I think it was just running as a capacitor start motor as one side or the run capacitor does not seem to be connected to anything. The only explanation I can see for swapping yellow and blue over is that one of them is shorting to (Or flashing over to.) earth. This is what Emgee suspected in his post at 18:37 on the 4th.

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.)
Keith, Was the picture of the connection box taken before or after you swapped the blue and yellow wires over ?

I would be interested to here comments from Emgee and/or John Fletcher as they may have spotted something I have missed.

 

Les.

Edited By Les Jones 1 on 07/02/2021 11:09:34

06/02/2021 17:48:12

Hi Keith,
Tracing the wires to the capacitors confirms that the markings fro the start and run capacitors is correct. The start capacitor will be the larger capacity of the two.)
When you refer to the switch is this the centrifugal switch and you managed to operate it manually ?
In your post at 23:12 on the 5th you say the resistance between K & S is zero ohms but today you say it is open circuit between K & S . Which is correct ?
I have tried to confirm that in your post at 13:12 on the 4th that the wiring in the motor connection box is the same as the diagram in the same post but could not see the marking of the top two terminals, Also I can not see which terminals some of the wires connect to. Can you confirm that it does match the diagram as you can move wires to see underneath them, (Apart from the yellow and blue being crossed over and assume this is after you swapped then over.)

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.

Les,

Edited By Les Jones 1 on 06/02/2021 17:51:06

06/02/2021 09:27:45

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 ?

060221.jpg

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.
With the 6 wires not connected to any of the terminals can you test for continuity between each of the 6 wires and all of the terminals. This is to see if there is any connections that are not visible. I suspect there is a connection that we don't know about as from the diagram I have traced out above swapping the blue and yellow wires is the correct way to reverse the motor and should not trip the breaker, I think the centrifugal switch is connected between terminals K and S. I would like to confirm this.There are a few ways to do this.1! dismantle the motor and follow the wires. 2 Spin the motor using an electric drill or other means to about 1500 RPM and check that there is no longer continuity between K and S, 3 With all the wires connect as originally connect your meter set to AC volts between S and K and apply power. There should be a short pause after applying power when there is no reading but once the motor is up to speed there should be some reading. This will probably be less than 240 volts.
4 Repeat the above but with the meter connected to K and Z. The meter should briefly read a voltage and drop to zero when the motor is up to speed.

Les.

05/02/2021 10:11:18

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 ?
I am reasonably sure that the centrifugal switch is between terminals S and K
Assuming that you have a multimeter do the following. Remove the 6 wires that come from inside the motor from the terminals.Take resistance readings between all pairs of those 6 wires. (I think that will be 15 readings.) Your meter test leads will have some resistance (Probably less than 1 ohm.) so subtract that value from the displayed readings.
Also measure the resistance between terminals S and K (I think these are connections to the centrifugal switch which will be closed when the motor is stopped. Post the results of these tests.

Les.

04/02/2021 18:04:30

The first reply to your post has a link to the instructions to post pictures on the forum,
Just click on the bold text to take you to the information.

Les.

04/02/2021 17:11:06

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 ?

Les.

Magazine Locator

Want the latest issue of Model Engineer or Model Engineers' Workshop? Use our magazine locator links to find your nearest stockist!

Find Model Engineer & Model Engineers' Workshop

Support Our Partners
JD Metals
emcomachinetools
ChesterUK
Eccentric July 5 2018
cowells
Warco
Eccentric Engineering
Subscription Offer

Latest "For Sale" Ads
Latest "Wanted" Ads
Get In Touch!

Do you want to contact the Model Engineer and Model Engineers' Workshop team?

You can contact us by phone, mail or email about the magazines including becoming a contributor, submitting reader's letters or making queries about articles. You can also get in touch about this website, advertising or other general issues.

Click THIS LINK for full contact details.

For subscription issues please see THIS LINK.

Digital Back Issues

Social Media online

'Like' us on Facebook
Follow us on Facebook

Follow us on Twitter
 Twitter Logo

Pin us on Pinterest