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Motor reverse switch 3 phase

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Me.23/01/2021 08:39:00
97 forum posts
13 photos

I want to fit a new rotary 3 phase motor reverse switch to my Mill.

Ive found a switch which is suitable but need advice on how to wire it.

The switch is an on-off-on rotary with 12 positions.

I have my 3 wires coming from the contactor, what goes where into the switch and what positions goes to the motor to enable it to run forward and then to reverse.

Martin Connelly23/01/2021 09:10:54
avatar
1648 forum posts
179 photos

The usual way 3 phase motors are reversed is to swap two of the phases feeding the motor. Without full details of the switch that is all that can be said for definite. There are probably lots of wiring diagrams for dedicated switches but since the dedicated switches will be likely be just 2 or 3 positions (forward/reverse or forward/off/reverse) they will not help. Can you confirm if the switch is 12 positions and not 12 connections. 12 position rotary switches are available but would usually not be suited to switching motor wiring.

Martin C

DC31k23/01/2021 09:26:31
384 forum posts
1 photos
Posted by Martin Connelly on 23/01/2021 09:10:54:

There are probably lots of wiring diagrams for dedicated switches but since the dedicated switches will be likely be just 2 or 3 positions (forward/reverse or forward/off/reverse) they will not help.

If we take the concept of a three phase reverse switch and the number '12', a good possibility is a fwd/off/rev/off cyclic mode of operation*. That would correspond to a 4 position switch in your terminology above so the diagrams for a 3-position one might at least give a starting point.

In the absence of a proper wiring diagram, use a continuity meter and make up a truth table for all terminals and all switch positions. Publish it here for review and we can tell you how to connect it.

Why not publish a link to the switch you have bought? Or if the source of your switch breaches the rules here, find an identical one from a 'clean' seller and point us in its direction.

* That is how the classic Santon ones work, even if the legend plate only has three marked positions.

John Haine23/01/2021 09:51:24
3627 forum posts
195 photos

Do you have a true 3 phase mains supply? If not and you're using a VFD it is usually a programming option to select reverse, no need to do anything in the wiring,

Me.23/01/2021 09:52:10
97 forum posts
13 photos

This is the switch - sorry i meant 12 connections - the description in the blurb says its for a motor F&R switch. I just need to know what connections to use - The truth table indicates which connections make and brake but I can't work out what is what in layman's terms.s-l1600.jpg

Me.23/01/2021 09:52:50
97 forum posts
13 photos

Yes true 3 phase supply 400v supply

DC31k23/01/2021 10:43:50
384 forum posts
1 photos

If it has a truth table, you are halfway there. Use your continuity meter to translate into layman's terms what the truth table is telling you.

Martin has already told you all there is to know on the subject: to reverse, swap any two of the three phases.

In the off position, the three incoming connections, call them U, V, W, will not connect to anything at all.

In the forward position, U, V, W will make to A, B, C respectively.

In the reverse position, U, V, W will make to B, A, C (or similar).

It is very important for your own safety and peace of mind that you understand what is going on rather than just follow a recipe that says 'connect this to that'.

Les Jones 123/01/2021 11:05:46
2214 forum posts
153 photos

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.
The make and model number of the switch may enable use to find the data on the switch.

Les.

Brian Morehen23/01/2021 12:26:42
avatar
140 forum posts
11 photos

The last one i fitted had a handle in the middle on the side which was of . Pushed up gave you one direction and down the opposite direction you the needed a separate Switch for on and off because the first one was just for rotation , I think this was a MEM switch.

Good Luck Bee,M

J Hancock23/01/2021 12:44:13
536 forum posts

Looks like a Blue Line switch.

Google 'Blue Line' , all the information you need is in their catalogue/ pdf page.

Martin Cargill23/01/2021 12:55:42
153 forum posts

Can you give us a picture of the truth table? It may be possible to use the switch to drop out the contactor (I assume your using a contactor/overload in the circuit) as this will prevent you from making a forward / reverse selection while the machine is running. Motors and mechanical bits tend not to like being changed from one to the other while running.

Martin

Me.23/01/2021 13:04:34
97 forum posts
13 photos

Thanks - Ive already had a look at the blue line page but still means nothing.

All I know is I have 3 wires from the contactor - 12 connections on the switch - 3 wires going to the motor (not including the earth).

If i connect the feed from the contactor to 1 3 5 where do the wires that feed the motor go ?? 2 4 6 ?? what are the other 6 connections for ???

Alain Foote23/01/2021 13:33:33
46 forum posts
6 photos

One phase say Red goes straight to the motor not via the switch! Then use the switch to reverse the other two phases round to reverse the motor.

Emgee23/01/2021 13:40:47
1909 forum posts
243 photos
Posted by Me. on 23/01/2021 13:04:34:

If i connect the feed from the contactor to 1 3 5 where do the wires that feed the motor go ?? 2 4 6 ?? what are the other 6 connections for ???

Seems you have a 4 pole switch so as said earlier you can use the 4th pole to switch the starter coil off to help reduce chance of going from fwd to rev without any delay.

You need to upload the schematic drawing recd with the switch to get sensible advice, or inform of the make and model of the switch.

Emgee

SillyOldDuffer23/01/2021 13:57:45
Moderator
6857 forum posts
1538 photos
Posted by Me. on 23/01/2021 13:04:34:

...

All I know is I have 3 wires from the contactor - 12 connections on the switch - 3 wires going to the motor (not including the earth).

...

That's all we know too! It's not enough. Can you identify the switch and share the truth table & diagrams please?

Dave

J Hancock23/01/2021 15:05:45
536 forum posts

This from the Blue Line on-line catalogue F071 plate, like yours.

Line Connection is terminal 2 (say red phase supply )

Switch Position 1 , term 2 will connect to term 3

Position 0 + off

Position 2 , term 2 will connect to term 1)

Line Connection is terminal 6 (say yellow phase )

SW pos 1 , term 6 will connect to term 7

SW pos 0= Off

SW pos2 , term 6 will connect to term 5

Line Connection is terminal 10 ( say blue phase )

SW pos 1 term 10 to 11

SW pos 0 = Off

SW pos 2 term 10 to 9

FOURTH POLE

14 to 15

OFF

14 to 13

not done it yet23/01/2021 15:34:50
5581 forum posts
20 photos

An interesting thread, with a comprehensive set of instructions from JH! I sorted out mine from scratch (about 6 years ago). Not too difficult when you have the right number of connections available (and a multimeter, or other circuit tester).

Me.23/01/2021 19:54:42
97 forum posts
13 photos

Many thanks for the very precise instructions. Exactly what I needed.

Me.23/01/2021 20:17:28
97 forum posts
13 photos

For those that asked the truth table for the switchI want to use.

41tgi+o1phl._sx342_.jpg

noel shelley23/01/2021 23:33:50
349 forum posts
9 photos

So, L1 to Ter 2, link 1 & 3 to A

L2 to Ter 6, link 5 & 11 to B

L3 to Ter 10 link 7 & 9 to C Correct ? Noel.

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