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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.

<< First < Prev 97 98 99 100 101 102 103 104 105 106 107 Next > Last >>
Thread: cutting round bar
21/08/2011 18:10:03
Hi all,
Here is a design for a power hacksaw using a washing machine motor that I found on the web.
I did not find the drawings that clear as I was looking for a sliding mechanism. It uses a double pivot system rather than a sliding mechanism.
Les.
Thread: Small machine casting kits supplier in UK?
16/08/2011 18:39:30
Here is my attempt at posting the link to one of the videos
 
 
Les.
Thread: Chemical milling
15/08/2011 22:25:24
Hi Brendan,
Have you considered using photographic film supported on a metal hub instead of metal with slots in it. If you could find someone with 21/4" square format camera you could create a large master on paper and photograph it at at calculated distance to produce the size you require on the negative. If it is just a simple quadrature encoder you want I may still have a copy of a program to print out an encoder.
Les
Thread: tilting vice
12/08/2011 17:51:16
Hi Mick,
Search on this forum for "sine vice". Nobby has a nice picture of his modified vice on that thread. I have one of these which I need to modify to get the pivot parallel to the base and the jaw faces.
Les.
Thread: speed control pcb for Clarke CL300 lathe
25/07/2011 23:17:04
Hi Mira,
Looking at the schematic it looks like contact on the reversing switch connected to P4 causes the motor to run at about half the maximum speed when in reverse. I suspect the trimmer P15 may be faulty. With no power to the board check the resistance between the slider of P15 and the end connected to -12V and make sure that as the trimmer is adjusted the resistance goes between zero ohms and about 30 - 50 k. Also check that the +12 V and -12V supplies are correct. (+/- 10%)
Richard Parsons comments refer to a fault he had on an AC induction motor. It is not relevant to your problem.
 
Les.

25/07/2011 09:46:58
Hi Mira,
Measuring the voltage on the optical couplers with a digital meter may not give meaningful results as it is not a smooth voltage change. It will be a square wave with varying duty cycle. You should see a change using an analogue meter as it will read the average voltage. As adjusting a trimmer seemed to fix the problem for a couple of days I suspect a capacitor or resistor changing in value as semiconductors usually fail suddenly. Electrolytic capacitors are the most likely component to fail. If you have access to an ESR meter (Effective series resistance.) then checking the capacitors with this would be a good place to start. Since I built an ESR meter I have found it a very quick way to find faulty electrolytic capacitors.
 
Les.
Thread: Raglan littlejohn Mk1.
24/07/2011 10:12:09
Hi donhe7,
If spooky is lucky enough to have that type of motor when he removes it from the washing machine I think it would be ideal.
Regards Les.
22/07/2011 10:34:10
Hi spooky,
Most washing machine motors are universal (Series.) design and run at quite high speeds (Up to 20000 RPM) so they would need a lot of gearing down. if you have plenty of room you could use the belt and pulley that drove the drum as the first stage of speed reduction. These motors are easy to reverse but they need a speed controller. I have never found a circuit diagram or data on the speed control IC used on the boards I have removed from washing machines. Here is a website with some information on using these motors.
They sell a speed controller using a TDA1085c IC. The data sheet for this can be found on the web and contains enough information to design your own speed controller.
Even though you could use one of these motors I think a normal 1400 RPM induction motor
(Or VFD inverter package and 3 phase motor.) is a better option.
Les.
Thread: mini lathe speed control
18/07/2011 22:40:35
Hi David,
There have been two threads on this topic. One in 2009 and one in 2010.
If you put cl300 in the keyword search box it will take you to these two threads. You may well find an answer there. If I remember correctly there are a few different versions of speed controller used. These threads should at least help you identify the version you have.
Les.
Thread: Nut runner
11/07/2011 09:03:23
Hi Dave,
0.118" * 25.4 = 2.9972 so a socket screw that uses a 3mm hex key should work.
The 4mm socket screws in the Screwfix catalogue use a 3mm key.
Regards Les.
Thread: Tearing hair out with disc sander
09/07/2011 20:23:58
Hi Charles,
First I will sate what my interpretation of the way the disk is mounted.
My understanding is that the bush is a good fit on the unthreaded part of the motor shaft and the alloy plate fits on the motor shaft between the bush and the retaining nut and washer. If the centre part of the plate is thick and a good fit on the motor then it will be how perpendicular this hole is to the surface of the plate that determines the axial run out of the plate. If the centre part of the plate is fairly thin and the hole a loose fit on the motor shaft then the run out will be more influenced by how parallel the front and back surfaces of the plate are and the axial run out on the face of the bush. You could true up the hole in the alloy plate using a boring head in your mill and make a bush so it again fits the motor shaft.
Regards Les.
Thread: Motor as Dynamo/Generator
06/07/2011 08:51:12
Hi Alan,
These comments refer to permanent magnet motors. (Which is the type you will probably use.) First choose a motor with a rated current equal to or greater than the current you require when used as a generator. The voltage output when used as a generator will be slightly less than the voltage required to drive the motor at a given speed. So if you chose a motor rated at 1000 RPM at 12 volts input I would only expect about 10 volts when used as a generator. As most small motors rotate at much more than 1000 RPM at their rated voltage you would probably need to select one of a much higher voltage rating. So if the motor was rated at 8000 RPM then you would need a motor rated at about 96 volts times about 1.2 which would be about 115 volts. To give the output you require do not expect the motor to be all that small. Even if you use a stepper motor an rectifier as John Stevenson suggests you will probably need a reasonable size motor. Wind up torches normally use a stepper motor but are geared to run at a very high speed.
Les.
Thread: Wiggly amps, NVRs and motors?
30/06/2011 17:50:02
Hi Cornish Jack,
The RCD detects a different type of fault to a thermal overload.
The RCD detects leakage current to earth. The normal domestic type trips at about 30 mA and does so quickly. The thermal trip trips if the current is too high over quite a long period of time (several tens of seconds.) It is designed not to trip with the high starting current which only occurs for a short time. If the thermal trips in the NVR are designed for say a 1/4 HP motor then if it was used with say a 1 HP motor they would probably trip even though there was no fault.
Les.
30/06/2011 14:40:09
Hi Cornish Jack,
The 5 amp fuse blowing could just be due to the high initial start current of the motor. Are you sure that the thermal overload trips in the NVR are a suitable rating for the motor. (What is the rating of the motor and what is the current rating of the trips in the NVR ?) Have you checked that the spindle turn freely ?
Les.
Thread: Wiring problems
29/06/2011 17:30:36
Hi Martin,
I do not think the two black wires should go to the same terminal on the motor.
I assume there is a reversing switch on the lathe. If so two of the four wires will go to the run winding the other two will go to the start winding. (I am assuming it is a single phase motor.) When you say it" throws the trip switch on the main power board" do you mean the consumer unit for the house / workshop ? If so do you mean the MCB for that circuit or the main RCD ? If it is the main RCD that trips then there is a fault to earth. If it is an MCB that trips then the lathe is drawing too much current.
(If is a RCBO for that circuit that trips then there is no way to decide if it is an earth fault or over current fault. ) I cannot read the letters against the top and bottom terminals on the motor. Could you say what these are labelled and add a copy of your notes. Do you have a multi meter to help identify the winding in case no one has a lathe with an identical motor to yours ?
Les.
Thread: Using the technology
28/06/2011 22:19:29
The pictures show up OK on both my PC's. One 32 bit XP pro with Firefox 4.01 the other window 7 64 bit with Firefox 5.0
Les.
Thread: Sparky Circuit Help wanted
27/05/2011 12:48:02
Hi Dick,
The difference in the pinout will mean that you will have to bend the leads so that they go into the correct holes in the PCB. (assuming it is built on a PCB.) All three leads still go to the same place on the circuit diagram as this does not relate to the physical construction of the transistors. The emitter is the lead with the arrow on it. The collector is the one that is the mirror image of the emitter but without the arrow and the base is the straight line. I hope this is clear as it is not easy to describe.
 
Les.
Thread: Reply to Post Disappears
26/05/2011 19:58:21
Hi Richard,
I am entering this reply win7 64 bit and IE9 64 bit as a test. I do not have access to the digital archive so I cannot test if that works on this system.
Les.
Thread: Internal Threading
25/05/2011 22:34:54
Hi Paul,
I think the tool you were using must be poor quality HSS or it was not ground correctly and was rubbing. If the hole you are threading is a small diameter it is quite difficult to get the tool shape correct. I would stick with HSS but others may recommend an indexable tool. It is a matter of personal preference.
Les.
Thread: Sparky Circuit Help wanted
25/05/2011 18:37:17
Hi Dick,
The 2N3702 is PNP so the BC212 should be OK to use. The other two also look to be suitable equivalents.
Les.
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