Barrel switch on this motor?

[Beanwood]

At the moment my Boxford has a light switch to start the motor (It's single phase, 240v) which I feel I should replace
I've done a little screwcutting in the last few fays, and whilst I'm not great at it yet - winding the lathe backwards by hand is quite slow, so I wondered about a revesing switch.
The motor windings appear to show I only need to swap two wires, and a cheap drum switch would appear to be all I need.
But I've read elsewhere on here a post about start windings needing to be swapped (@Rrobson ?) so thought rather than launch into a capital expenditure (£12.85!!) I'd ask the collective

Can I just wire the output feed from the switch to the A1 and A2 points - or is it just the internal motor windings (Black and Red) that swap, with A1 remaining neutral and A2 remaining live (As currently)

 

[Rrobson]

With this you’ll have live and neutral on either a1 or a2, and to change direction you’ll swap the motor leads currently attached to a1 and a2 by physically unbolting and re-attaching the leads on the other posts.
If using a barrel switch you need to have the live lead wired through the switch so the motor isn’t energised without the start winding also energised because it’ll just buzz and overheat.
You also need to wire the start winding wires through the barrel switch. To do this you remove the start winding wires from their posts, lengthen them using your preferred wire joining method and wire them through the switch terminals that swap the output over. The output is then connected to the motor start posts along with live and neutral. You could wire the neutral through the switch too but it’s not necessary. If you want to neaten things up you can also wire the live and neutral post switch back into the switch start winding output terminal so youve only got two wires going back to the motor but it can sometimes get confusing if you do this.
It’s not neat but easy once you get to grips. There are a few videos on YouTube that show you how to wire motors through a barrel switch.

 

[Agroshield]

The switch has five terminal pairs. It only shows the logic for three of these pairs. It is workable like that but could be made better if you can figure out the logic of the other two terminal pairs. You want one of the unused pairs to do the same as the top pair in the diagram.

I would use a single five core cable between switch and motor (output) and a three core cable going into the switch (input).

Input (let us say this is on the RHS of the switch):

a. Live (top RHS of switch diagram). Daisy chain to second one down RHS in switch diagram.
b. Neutral (fourth terminal down RHS in switch diagram). See if either the third or the fifth terminal pair in the switch behaves as the top terminal of the switch. If they do, you can daisy chain the neutral to that one on the RHS. If not, connect the outgoing neutral (letter D below) to the incoming neutral (and it will be unswitched).
c. Earth. Connect to outgoing earth.

Output (LHS of switch):

A. Switched live (top of switch diagram)
B. 'Swappable' live (next one down)
C. 'Swappable' neutral (4th terminal down in switch)
D. Switched neutral if possible (see b above). Join to incoming neutral (4th teminal down RHS) if not.
E Earth. Connect to incoming earth.

Motor end:

Separate each motor wire onto its own stud. Put A and D of the switch output to one set of these (e.g. red/black). Put B and C of the switch output to the other two. If the motor does not follow the wording on the switch (or does not go in the right direction for you when you move the lever to the left), swap A & D only at the motor end.

---

One of the motor winding ends should always be off or live.
The other end of that winding should always be off or neutral (the off is switch-dependent)
One of the motor winding ends should be live, off or neutral (in that order).
The other end of that winding should be neutral, off or live (in that order).

 

[not done it yet]

Cheap drum switches are for selecting the direction, not really for switching on or off. You would need a heavy duty drum switch for that.

 

[Beanwood]

Cheap drum switches are for selecting the direction, not really for switching on or off. You would need a heavy duty drum switch for that.

Not quite understanding you - it's rated at 60A - which is a hefty chunk more than a 550W motor can pull?
(I could have mentioned I'm planning a NVR switch ahead of the drum switch, and ideally an emergency mushroom ahead of that.)

 

[brightspark]

Not quite understanding you - it's rated at 60A - which is a hefty chunk more than a 550W motor can pull?
(I could have mentioned I'm planning a NVR switch ahead of the drum switch, and ideally an emergency mushroom ahead of that.)

if thats the cheap drum switch from china which it looks like . i have one and you can can hardly wire 1.5mm cable in it .be lucky to get 16 amp through it

 

[Beanwood]

if thats the cheap drum switch from china which it looks like . i have one and you can can hardly wire 1.5mm cable in it .be lucky to get 16 amp through it

Agreed - but even with blatant exaggeration/optimism on behalf of the vendor - I'd still hope it could manage a 550w motor (1.5A?)

 

[brightspark]

Agreed - but even with blatant exaggeration/optimism on behalf of the vendor - I'd still hope it could manage a 550w motor (1.5A?)

it will do not much room in them though best wiring in a bit of 1.5mm flex max

 

[Wedg1e]

Don't forget you need to let the motor spin down before you reverse it, as if it still has enough momentum it'll ignore the reversed polarity and carry on spinning the same way.

 

[Bsmith]

Glad you have the lathe going. I also had a problem trying to work out the wiring with one of these switches, but sat down one day with the switch and multimeter and managed to find a way by adding links to the switch connections.
For what it is worth, my post....

Cable size?

Elect has drawn me up a diagram so I can wire my lathe with a reverse switch, he told me to get a piece of 6 core cable on Monday for between the switch and motor. Can someone tell me what size of cable I would need to ask for please? If I remember right it's sold by 2.5, 3.5 etc. 1,1/2 hp...

www.mig-welding.co.uk

I since changed to a 3 phase motor and vfd.