Perfect solution

This topic has 7 replies, 5 voices, and was last updated 4 June 2019 at 19:18 by Plasma.

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3 June 2019 at 20:48 #412445
Plasma
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@plasma
Just an example of how this site serves to pool knowledge and assist members with all manner of queries.

I bought a used single phase motor to power a Smart and Brown model L lathe but the direction of rotation was wrong.

A quick search thru previous posts revealed a possible solution:

Take off the end caps, turn the rotor shaft round so the pulley is on the opposite end to when you began and button it all back up.

Hey Presto, direction of rotation reversed. Obviously it still rotates the same way but moving the rotor is the same as turning the motor housing thru 180 degrees. Something that was not an option in the lathe housing.

Thank you model engineer for saving me from distraction.

Best regards Mick
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3 June 2019 at 20:48 #35498
Plasma
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@plasma
3 June 2019 at 22:12 #412466
Kiwi Bloke
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@kiwibloke62605
Bit of a faff to go through all that, should you want to run the lathe in reverse (quite useful, sometimes)… Were the ends of the start winding inaccessible? A reversing switch is useful.
4 June 2019 at 05:46 #412486
not done it yet
Participant
@notdoneityet
Induction motors are easily rewired to run in the opposite direction. Usually (often?) a wiring connection diagram is included within the terminal cover? Not all single phase motors are of that type, mind, but most are.
4 June 2019 at 08:22 #412497
Plasma
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@plasma
Wiring is not a strong suit for me so some other means was simpler.

Also the model L has a screw on chuck so reversing isn't a great thing, orher than for tapping.

Maybe I will learn a bit more about reversing switches.

Regards Mick
4 June 2019 at 10:00 #412512
john fletcher 1
Participant
@johnfletcher1
Not sure about it being SIMPLY putting the rotor and centrifugal switch the other way round. What then happens to the two wire from the start winding ? Some motor have only three wires and were not intended to be reversed, drilling machines come to mind. I've reversed the DOR of several friends lathe motors and during course of conversation I've asked do you need the facility, not at all but might come in handy,comes the answer. I wonder why Myford used those Dewhirst switches for ON/Off as well as F&R just not adequate and they should have used a proper motor starter with No Volt release. John
4 June 2019 at 16:03 #412568
Neil Wyatt
Moderator
@neilwyatt
It's a simple solution and 100% OK. The reversal of the rotor of an induction motor doesn't change anything in practice, it still rotates in the same direction – but the drive shaft stick out the opposite end so its sense of rotation relative to the body is reversed.
4 June 2019 at 19:18 #412624
Plasma
Participant
@plasma
Neil, that's what I deduced from the other thread, but it's good to have it confirmed by you. There is no centrifugal switch on this motor in any event so that's not a problem.

I believe it's just as if I had turned the motor round but obviously I couldn't do that in the confines of the lathe cabinet.

As I said maybe a reversing switch set up would be good for tapping threads with the capstan unit.

Best regards mick
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