connections

[Terry HoldenParticipant @terryholden56477]

I want to fit a new modern tumbler type reversing switch to my existing Super 7 motor which is a Beaston 0.55 kw 3/4 HP 240 v. The switch output wires are shown as UI,U2,Z1 and Z2.

The motor connections are AZ, A, purple wire removed from post AZ and thin red wire removed from post A.

I think U1 is main live to go to post AZ. U2 is neutral to go to post A and that Z1 and Z2 are start circuit connections to go to the purple and red wires which reverse the motor. I think Z1 and Z2 can be reversed to match the direction of the motor with the switch.

If anyone has recently done such a change would be very grateful to receive confirmation I have this right (or wrong ! ) before I proceed.

Can confirm that on wiring diagram with switch U1 is is connected to live and U2 connected to neutral.

Thanks

[Terry HoldenParticipant @terryholden56477]

Connections for new reversing switch

[noel shelleyParticipant @noelshelley55608]

I would counsel against doing this as the most likely outcome is to unscrew the chuck on an S7. I have one on mine as thats how it was wired and I'm to lazy to change it – I also never use it ! If you do do it, then you will also need a contactor as this switch should never be used as a stop start switch – only to reverse the direction of rotation of the motor – a failure to do this will burn out the contacts. Many do it but on a myford, not a good idea !!! Noel.

Edited By noel shelley on 06/02/2021 14:40:31

[Terry HoldenParticipant @terryholden56477]

Many thanks for reply. Yes I am aware of the risk of reversing the chuck but it was never a problem with my previous 7 over many years. Just need to be careful. Would still like to connect up this new switch but will also use DOL starter switch for off / on duties.

The internals of the new switch I have are illustrated in the thread under General Questions titled Reversing Motor by Keith Jenkins.

Can any body confirm the wiring connections please.

Thanks

[Harry WilkesParticipant @harrywilkes58467]

Posted by noel shelley on 06/02/2021 14:39:43:

I would counsel against doing this as the most likely outcome is to unscrew the chuck on an S7. I have one on mine as thats how it was wired and I'm to lazy to change it – I also never use it ! If you do do it, then you will also need a contactor as this switch should never be used as a stop start switch – only to reverse the direction of rotation of the motor – a failure to do this will burn out the contacts. Many do it but on a myford, not a good idea !!! Noel.

Edited By noel shelley on 06/02/2021 14:40:31

i have had reversing on my S7 for 4 years and have yet to unscrew my chuck, it is however a point to bear in mind. Before fitted an VFD I fitted this type of reversing switch *link* along with the original MEM starter

H

Edited By Harry Wilkes on 06/02/2021 15:35:55

[SteviegtrParticipant @steviegtr]

Sorry this is a bit of a fag packet drawing, but was in the drawer of the lathe when i bought it. Super 7.

Steve.

[SteviegtrParticipant @steviegtr]

Here's some more from the Myford manual. Hope they help.

Steve.

Edited By Steviegtr on 06/02/2021 15:58:28

[Terry HoldenParticipant @terryholden56477]

Thanks Steve those are the connections for a Dewhurst switch. The one I have is similar but with different connections. I still need to check that I am getting the right connections between switch and lathe as in my second paragraph at start. Thanks for the help.

[David George 1Participant @davidgeorge1]

My wiring for the reversing switch goes through the reversing switch. The power is diverted through the spare 4 -8 contacts so that the power to the on off switch is turned off if someone tries to reverse the motor using the reverse switch with power on.

David

[SteviegtrParticipant @steviegtr]

Posted by Terry Holden on 06/02/2021 15:55:29:

Thanks Steve those are the connections for a Dewhurst switch. The one I have is similar but with different connections. I still need to check that I am getting the right connections between switch and lathe as in my second paragraph at start. Thanks for the help.

Sorry just added another type of sw.

Steve.

[Terry HoldenParticipant @terryholden56477]

Thanks everyone for your replies but above information relates mainly to fitting a Dewhurst switch. My new switch has different connections.

from my first post

"I think U1 is main live to go to post AZ. U2 is neutral to go to post A and that Z1 and Z2 are start circuit connections to go to the purple and red wires which reverse the motor. I think Z1 and Z2 can be reversed to match the direction of the motor with the switch."

Can anyone who has done this confirm what I think is correct ? Alternatively is there anyone here who is an electrical expert who I could send the diagram and information to by e mail to get advice.

Terry

[Trevor Jones 11Participant @trevorjones11]

Hi Terry, I'm in the same situation, except that I'm wiring up a Crompton-Parkinson 3/4 hp motor for my old Myford S7. It caused my a little bit of effort as it only had three terminals – two of them jumpered together – in the motor junction box with another two field wires on one post. I had to slightly dismantle it to confirm which were the start and run wire pairs, remove the jumper, fit an extra 3BA terminal post on the board and wire all it up nicely with four distinct terminals.

I think your initial statement is almost correct. Z1 and Z2 will be the start field terminals and are the ones that get reversed by the switch to change run direction.

I think that main live should go to post A and neutral should go to post AZ. But happily it doesn't really matter as the run field is not very fussy that way.

And of course you need a No Voltage Release switch before the reversing switch.

[Terry HoldenParticipant @terryholden56477]

Thank you very much for your reply Trevor. Think that with the information I now have I am good for go. I have DOL

to wire in as well. Thanks Terry

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