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: Reversing Motor|
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 ?
|Thread: Motor reverse switch 3 phase|
You would need an extra stop button and start button.
Edited By Les Jones 1 on 02/02/2021 12:00:15
Here is a diagram of how I suggest adding the reversing switch.
Connect the reversing switch as in Martin's drawing posted at 16:13 on Jan 24th.
It would be better if you can provide information on the existing so we can tell you where to break the feed to the contactor coil. all of the interlocks, the thermal overload contacts and the stop button will probably be in series with the coil. Also we don't know if the contactor coil is powered between phases, between a phase and neutral or from the secondary of a low voltage transformer. Your existing wiring diagram should provide that information.
Reading through the thread again I notice you do have a contactor so here is a suggestion that would ensure the contactor dropped out when the switch passed through the middle off position.
Connect L1 directly to A on the motor.
Connect L2 to 6 and link 6 to 8.
Connect L3 to 10 and link 10 to 12
Link 1 to 3 We will call this point X
Link 2 to 4 We will call this point Y
Break the feed to the contactor coil and connect the two ends of the break one to X and one to Y
Edited By Les Jones 1 on 24/01/2021 14:56:22
From the truth table Noel's instructions will only work in position 1. (Post 23/01/21 at 23:33)
Edit. I see Martin has beat me to replying. His information will also work
Edited By Les Jones 1 on 24/01/2021 10:32:42
It looks like there is information on the left hand side of the switch between the connections. there is probably the same on the other side. If you post pictures of both sides it may avoid you having to meter out the connections.
|Thread: Replacement motor control box for mini mill|
As John Rudd mentioned DON'T try to use a scope to fault find unless you supply the speed controller from an isolating transformer with a floating secondary. I suggest using a 60 or 100 watt incandescent light bulb as a load in place of the motor connected directly to the board. Also don't forget to link the connections that normally go to the interlock switches.
Here is a schematic for the XMT-2335 board in case you do not have one.
Arc Euro stock them under Seig X2 spares but they are £136.31.
|Thread: VAT changes post Brexit|
Re my post on 08/01/21. The spindle that I ordered from China arrived today. There was nothing to pay.
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