Motor reverse switch 3 phase

[BazyleParticipant @bazyle]

mmm probably very helpful thread for future fererence
but
If I were a beginner with limitted elctrical knowledge I would be well confused and a bit worried. Lots of numbers and letters but i'm not seeing nice clear statements like "mains supply" and "Motor wire". I wonder if someone could draw a nice diagram goinf from the mains pug to the motor?

[Les Jones 1Participant @lesjones1]

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 B on the motor to 5 and link 5 to 11

Connect L3 to 10 and link 10 to 12
connect C on the motor to 7 and link 7 to 9

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
This will cause the contactor to drop out when the switch passes through the middle off position.
You will then have to press the start button again after the switch has been set to either the forward or reverse positions.
As you have a contactor all three phases will be disconnected from the motor when the switch is in the off position.
Even if the switch is set to forward or reverse if the motor has been stopped with the stop button none of the phases will be connected to the motor. If you post the exiting wiring diagram and information on the contactor one of us will be able to tell you a suitable place to break the feed to the contactor coil.

 

Les.

Edited By Les Jones 1 on 24/01/2021 14:56:22

[Me.Participant @me1]

I had thought of that option and I suppose it would be safer I suppose if I did it that way – For some reason my PC isn't allowing me to upload any photos – pictures so I can't draw out what I have got but its very basic wiring.

3 phase wires + Neurtal which goes into the coil of the contactor

1 phase wire goes into the coil of the contactor (hager – 240v coli) and into the switch – one "off" and one "on" wired in series.

When I press the "on" button it energises the coil which brings in the contactor – which then feeds my (very) old existing lever switch. Up for forward and down for reverse.

To stop the motor I bring the lever switch to the middle which kills the power to the motor and then I press the "off" button.

I was just getting my head around the Linking terminals now it looks like I'm gonna have to add more….

Ive not brought the rotary switch yet so if i need a 16 terminal switch then that's ok.

[john fletcher 1Participant @johnfletcher1]

I have been following this discussion with interest, so would some one tell the part number for this switch and where can I get the truth table or was it included with the package. John

[Martin ConnellyParticipant @martinconnelly55370]

This is the basic circuit that does not involve the contactor circuit.

Martin C

Edited By Martin Connelly on 24/01/2021 16:06:19

[Me.Participant @me1]

Hi John I just went on Ebay and inputted – 3 phase motor reversing switch.

[Me.Participant @me1]

Wow Martin – Thanks- that is exactly what i needed – it is so much easier to understand when written down like that.

I can't thank you enough –

I wonder if you could do one with the other option with the It breaks the feed to the coil on the contactor as suggested by Les

[Martin ConnellyParticipant @martinconnelly55370]

This is the one where the top contacts are used to latch the contactor as described by Les. The contactor may have terminals just for this external latching with a link in place.

Martin C

[Les Jones 1Participant @lesjones1]

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.

Les.

[Me.Participant @me1]

Two pictures of the contactor and switches as fitted to my Mill.

Brown Black and grey input from the mains at the top.

the 3 pairs of yellow blue and red are the feed to the two motors. Which I am fitting the new rotary switches too.

The brown leads go to two momentary switches the green one energizes the contactor and the red one turns it off.

The blue wire sticking out at right angles is the neutral.

Where do I need to break the leads to add my new switches as per Martins wiring diagram ( X – Y connection)

Or do I need to replace the momentary switches for something else.

[Les Jones 1Participant @lesjones1]

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.
Remove the link wire between the bottom mains input (I can't read the marking on it.) and the stop button. Connect the point X on Martins diagram to bottom mains input terminal on the contactor, Connect Y on Martin's diagram to the connection on the stop button that you removed the link from.

Les.

[Me.Participant @me1]

HI Les

Many thanks again for your very easy to understand description and diagram. I will do as suggested.

As I will have two rotary switches – one to control the main spindle motor and one to control the table feed, do I take a separate feed to each X point on each switch or do I add the switches in series.

i.e "Brown (feed) – X-Y-X-Y – Stop".

Steve

[larry phelan 1Participant @larryphelan1]

Just as a matter of interest, why would you need to run the mill in reverse ?

[Les Jones 1Participant @lesjones1]

Hi Steve,
The way you have show will work but it would make more sense to have a separate contactor for each motor.
Every time you change the feed direction the spindle motor will also have to stop and start.

Les.

[Me.Participant @me1]

Thanks Les _ I can do that I have a spare contactor the same as the picture.

Will I need two more on/off buttons as well ?

My Idea was

1.Press the button to turn the contactor on

2.Switch the main motor on (rotary switch)

3.Switch Table feed on (rotary switch)

4.switch to the "0" position when finished cut

5.Press the off button to turn main power off.

*i'm now in need to know the answer to Larry's Question – why does the main spindle motor need to run in reverse ???*

It has the option too on the "old switch panel" but when would you ever need to make a cut with the spindle in reverse ??

[Les Jones 1Participant @lesjones1]

You would need an extra stop button and start button.
Your suggested switching sequence is not a good one as you are using the reversing switch to switch under load which will shorten it's life. You should set the direction then switch on and off using the start and stop buttons.

I have used my mill in reverse on a few occasions. I think it was to use a boring tool from my lathe mounted in a boring head on the mill.

Les.

Edited By Les Jones 1 on 02/02/2021 12:00:15

[Me.Participant @me1]

Thanks I will get two more switches and have each contactor control a separate motor – with your help I will get this done…..

[Martin ConnellyParticipant @martinconnelly55370]

Why do you need reverse on the mill? Knee raise/lower motor, table drive left/right motor. Head raise/lower motor. Tapping head with friction drive (not auto reverse) in the spindle.

Martin C

Edited By Martin Connelly on 02/02/2021 21:07:19

[Me.Participant @me1]

Thanks for the reply – but mine doesn't have a motorised quill or Knee raise/lower. My Mill has spindle drive motor and table feed motor left/right.

There must have been a reason for them to design the machine to have the main spindle motor to reverse.

NB: New Rotary switches installed and have just order two new Auxillary contactor blocks NO/NC type to control the other contactor. I think I will soon be ready to use the Mill – after almost 6 months of restoration and heartache…….money…… time….and trouble. But its worth having this almost 70 year old machine back up and running.

[Me.Participant @me1]

Its alive – and works perfectly.

Took my first cuts last night and its very stable. I machined a few bits of mild steel with a nice and sharp brand new end mill. Only took 10thou cuts to start, slowly built my confidence and went for a 25thou cut at 15mm deep. Looks good.

The fun begins.

Thanks for all those that helped with the new switch wiring it works perfectly and now no chance to put the motors into reveres by mistake.

[Author]

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