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: Blown band saw circuit.|
I have just been reading through the thread again. I had misread the first post and thought that the motor ran when the start button was held pressed but you actually said when the TRIP SWITCH was held pressed. All I have said so far is not relevant. If you have to keep the trip switch pressed in then the motor is taking too much current or you have been supplied with the wrong current rating of trip switch. (You should never hold a trip switch in as it is designed to remove the supply id the load is taking too much current.) Sorry for my error in reading your first post.
Edited By Les Jones 1 on 29/08/2020 18:11:45
Hi Phil, Many of these NVR switches do not even have a separate maintainer contact. If It turns out that the only fault is the maintainer contact (2 to 6) then I am going to suggest linking 1 to 4. I think it is unlikely that the 2 to 6 contact AND the coil have both failed.
I am even more confused. Are you using an analogue or a digital meter and if it is digital is it auto ranging on the resistance setting ? I don't understand the 1 reading. (You don't say if this is 1 ohm, 1 K ohm or 1 Meg ohm.) Normally on a resistance range with the test probes not conneted to anything or each other the meter would display something like ol to indicate the resistance between the probes is higher than the meter is capable of reading. If the probes are shorted together it would read 0.00. (If it is set to al low resistance range it can give a small reading of probably les than 1 ohm which will be the resistance of the test leads.) Does your meter behave this way ?
Note to Phil. This type of NVR switch does not have a normal start an stop button. The start button just manually pushes the solenoid to the closed position and the stop button just forces the solenoid to the open position.
Edited By Les Jones 1 on 27/08/2020 15:00:05
I assume that when you say "nothing" you mean infinite resistance. If not what do you mean ?
What was the resistance reading between 1 and 5 ? (I don't understand what you mean by "thing".)
Edited By Les Jones 1 on 26/08/2020 17:43:33
If the fault is the contact set 2 to 6 then it should be possible to get it to work by a small change to the way it is wired.
This is my interpretation of the wiring.
Contacts 3 to 7 and 4 to 8 must be working as the motor runs while the start button is held in, (The start button just pushes the solenoid in,)
There is probably a centrifugal switch inside the motor that disconnects the start winding when the motor is up to speed. Probably an NVR switch such as this can be used. (There are also many advertised on ebay.)
It sounds like either the coil on the coil on the contactor is open circuit or the maintainer contact is not holding the coil in after the start button has been pressed. The stop button will be a normally close push button and if that was open circuit it would also prevent the the coil from holding the contactor in. I assume the rectangular thing with 8 connections is the combined contactor and start and stop buttons. you have not shown which connections go to the coil or the layout of the contact sets. I have tried to find a picture of your contactor assembly but failed. Some pictures of the contactor may help in understanding the contact and coil connections. I think a standard NVR switch can be made to work.
|Thread: Coping with voltage spikes|
Tim, You are going to have to provide more information on the "LED". A single actual LED (I am assuming it is a white LED as different coloured LEDs have different forward voltages.) would have a voltage of between 3.0 and 3.6 volts across it when driven with it's rated current. As you are calling it a 12 volt LED it must contain something to limit the current and it may consist of more than one actual LED. Until we know more about the "LED" we can't work out a possible reason for it failing.
|Thread: Death of a PSU|
The TNY264 is also a 7 pin low power switch mode regulator chip. It would be nice to know the part number of the chip on the board as the picture is not good enough to read it.
|Thread: Son`s mini lathe Clarke CL300|
This is a link to the manual for the CL300M which contains a wiring diagram but not a schematic of the board. (Which I have not been able to find.)
Am I correct that when you say " mixed up he has said they were the ones going to the emergency stop button the on and off." that you mean that he connected the output of the on/off switch to terminals K3 and K4 and that he connected the wires from the emergency stop switch to terminals L1 and L2. If so I don't see that this would cause the varistor to fail but it almost certainly would have damaged other components as he connected the mains to the low voltage part of the board. The varistor is probably connected directly across the mains input to the board (terminals L1 and L2) so I think this just failed or failed due to a high voltage transient on the mains.
Telling us which wires you connected to the wrong place may help to identify what damage you have done. Tell us the correct places the wires should connect to and where you actually connected them. can you also post a picture of the under side of the board near the burned area.
|Thread: Voltage feeding DRO "usb" digital scales?|
I have always supplied this type of scale with 1.5 volts when using home made remote displays. I think you will find the remote power connections connect directly to the internal battery contacts. The recommended silver oxide cells are rated at 1.55 volts when new. I have used an LM317L to provide the 1.5 volts supply from the 5 volt rail for the logic in my remote displays. Although USB connectors are used on these scales they DO NOT use USB protocol.
Edited By Les Jones 1 on 01/07/2020 09:10:19
Edited By Les Jones 1 on 01/07/2020 09:25:05
|Thread: 3 Phase in a Model Engineers workshop|
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