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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: Electrolytic capacitor
17/03/2020 11:30:50

They were probably in series as the working voltage of supercapacitors is quite low. (Less than 6 volts from memory.) So the series configuration was probably to get the required voltage.

Les

Thread: At my wit's end - need help please
16/03/2020 19:57:12

As John says take some pictures of the inside of the base and tell us if any of the wires from the inside of the motor are connected to anything else such as the on/off switch, mains input cable and capacitor if there is one. I expect there to be three (Or possibly 4 wires wires) coming from inside the motor to the base. If there is no marking on the wires to identify them put some markers on them so that we can identify them when we are telling you what resistance measurements to take.Take a few pictures from slightly different angles so that we can see where wires go without being obscured by other wires. What is the history of the grinder ? For example was it given to you in a dismantled state. Did it stop working and you dismantled it without noting the connections ?

Les.

Thread: Any motor experts on the forum?
08/03/2020 11:58:02

I too have never heard of " an induction motor with a permanent magnet rotor ". I think Brian's question about it being a 3 phase motor that has been modified needs to be answered.

Les.

Thread: Chester Model B
16/02/2020 14:55:19

I assume that the black wires (U1 & U2) feed the main winding and the red wires feed the auxiliary winding (Via the capacitors on the motor. If this is so then remove both links. Connect wire U1 to terminal U1. Connect wire U2 to terminal U2. Connect wire V1 to terminal V1. Connect wire V2 to W2. Before doing this confirm that the 4 wires are connected as I assume. WITH NO POWER TO THE LATHE confirm that with the forward reverse switch in one position (Forward or reverse. Ignore the off position if it has one.) you get an almost zero resistance reading between wires U1 and V1 and between wires V2 an U2. In the other position you get almost zero resistance V1 and U2 and between V2 and U1. If you do not have a meter I can suggest a method using 4 mains voltage lamps.
If you connect it up and forward and reverse are the wrong way round then swap over wires U1 and U2.

Les.

Thread: Lathe RPM meter not working
31/01/2020 09:18:04

Looking at the schematic posted in the second post the only output seems to be via the 10 K resistor. This would not provide enough current to power the tachometer electronics. I suspect the 10 K resistor is the load resistor for the optical sensor. (If it does use an optical sensor.) There must be some other source of power to the tachometer. For us to be able to help you you will need to provide some more information. Does it use an optical sensor or some other method ? Can you post pictures of all the circuit boards in the lathe and the speed sensor so we can get an idea of how the low voltage to the tachometer is supplied ? Can you include pictures of the component side and the etch side of the auxiliary control board so we are sure it is the same as the one posted.

Les.

Thread: Machining a 70mm hole in steel
22/12/2019 09:44:48

I had the same thought. It would be better if the question gave some more detail. I ASSUME 65mm is the thickness. The answers would be very different between a block 80mm square and a block 1 metre square. (Unless he has a VERY large lathe and mill.)

Les.

Thread: Scam alert
19/12/2019 13:05:10

This is slightly off topic. A short time ago I was ordering an item fro Amazon and I was in no hurry to get it. I clicked on free delivery thinking it was the free about 5 day delivery but it was for Amazon prime one day delivery. I tried to get back to select the 5 day option but nothing I tried worked, I even tried cancelling the free prime trial offer.I ended up cancelling that order and creating a second Amazon account using a different email address. Instead of taking a few minutes to order the item it probably took about an hour.

Les.

Thread: Three phase Variac Internal wiring
15/12/2019 12:49:33

I agree with Bill that it does not look like a three phase variac. It does not even look like single phase variac.(Although the information on the label would match a single phase variac.) Can you post a picture of the inside of the item. If you are familiar with single phase variacs then a three phase one just looks like three single phase ones mechanically linked together.

Les.

Thread: Lathe annoying 50Hz hum
01/12/2019 16:38:36

Have you checked that it is not the coil in the NVR switch that is causing the hum ? Try disconnecting the output of the NVR switch and see if the hum is still present.

Les.

Thread: Mitutoyo DRO Fault
17/11/2019 16:02:59

Your description " with similar results " is not clear. If you have proved that one of the "amplifiers" does not work in either position with either scales then that "amplifier" is faulty. Conversely I assume the other "amplifier" works in either position with either scale. I don't think the fact that the display will change between metric and imperial indicates anything about the "amplifiers" Even if you had a schematic of the amplifier I don't think we could talk you through diagnosing and fixing the fault on the faulty "amplifier".

Les.

17/11/2019 10:36:36

My understanding is that you have swapped over the two cable connections at the top right and this proved that both scales work on one of the inputs but neither works on the other input. You should now be able to prove it the fault is one of the "amplifiers" or deeper inside the DRO by swapping the positions of the "amplifiers" in the DRO. So does it always fail with the top position (For example.) or does it always fail with the "amplifier" that WAS in the top position (For example.) ?

Les.

17/11/2019 09:03:59

In your first post I got the impression that each scale connected directly to the DRO (The unit with with the displays for the 2 or 3 axis's and the buttons for setting zero points etc.) I interpreted your use of the word amplifier as the internal circuits on the DRO that convert the signals from the scales to the logic levels that connect to the internal micro controller. I am assuming the scales are glass quadrature scales with 2 or possibly 3 output signals that are either sine wave or square wave. Are you now saying that the output of each scale goes via an "amplifier" before feeding the inputs on the DRO. Can you clarify how things are connected together with a block diagram.

Les.

Thread: Headstock Dividing Attachment from Hemingway
10/11/2019 12:55:11

I have done a similar thing using the rotary table to drive the spindle. The table is attached with an adaptor that fits into the end of the spindle and the drive is transmitted with an expanding collet. The spindle supports the weight of the rotary table and the rotary table base is prevented from rotating with an arm attached to a fixed point on the lathe.

img_1457 (medium).jpg

img_1458 (medium).jpg

The pictures above show it mounted on my Chester DB10G. The second picture shows how the rotary table base is prevented from rotating.

Les.

Thread: Motor wiring
14/09/2019 10:52:58

It looks like that only 2 connections are used on the terminal strip so live and neutral will connect to them. It looks like there is no way to reverse it. If I was connecting it up I would first remove the two screws that hold the terminal strip to the motor to see if there are any wires connected to the underside of the terminal strip.

Les.

14/09/2019 08:43:44

Just swapping over live and neutral in the motor should make no difference BUT there are probably more than two terminals (Plus earth.) in the connection box on the motor. IT DOES MATTER WHICH TWO TERMINALS THAT THEY ARE CONNECTED TO. Post a picture of the connection box and any information that may be inside the lid of the connection box if you are not sure which two terminals to connect to.

Les.

Thread: Power feed for mill table
07/09/2019 16:59:55

Try monitoring the voltage from the power supply. I suspect the power supply may be shutting down with the increased load when the speed controller is turned up. You could also try connecting the motor directly to the 12 volt supply.

Les.

Thread: Mains power supply for 12v dc motor
31/08/2019 14:40:16

Hi William,
I don't think that is really suitable for your purpose. It will be designed to control the speed of a motor designed for around 180 to 220 volts. It will provide no isolation from the mains. It will probably use phase control so when it is set to a low speed (Low AVERAGE voltage.) the output will be short pulses of a much higher peak value than the average output voltage. I am assuming that your saw is designed for an 18 volts battery.

Les.

31/08/2019 09:14:55

Hi Michael,
Thanks for pointing out the information I missed in the first post. One point about using PC power supplies is that some of them require some load to be put on the +5 volt output before the rated current can be drawn from the +12 volt output..

Les.

30/08/2019 22:36:05

You will need to know how much current the motor takes so you can obtain a power supply capable of driving it.

Les.

Thread: How to wire a 4QD controller
28/08/2019 19:50:48

I had not heard of 4QD so I had a look at their website. They make more than one controller so telling us which one it is and details of what you don't understand would increase the chances of having your problem solved.

Les.

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