PDA

View Full Version : Single Phase Reversible Motors...Wiring Question.



seanz
04-07-2015, 06:26 PM
I have an old machine in the shed that is showing its age. One of the ways it does this is by having a metal shield over it's control switch which has seen better days and cracked insulation on the leads. Leads are now replaced.
It's 3 position switch, Forward/Off/Reverse. Looked a bit tatty and I had a NIB modern switch that I thought would replace it but when I checked the diagram on the new switch it didn't make sense.
The old switch has 3 wires in and 4 wires out. The new one appears (not the best diagram) to have 3 in and 3 out. Any ideas? The motor spec plates says it's good for either 120 or 240 volt (we're240v ) so the questions open to the whole board. :)

And, how do you make a single phase motor reversible?

Might drag the NIB switch out again and check the diagram...but (I thought) the poles weren't all that well marked.

the_gr8t_waldo
04-07-2015, 08:10 PM
What type of switch is the old? While we at it.. What's a NIB switch?

Paul Pless
04-07-2015, 08:13 PM
what kinda machine?

seanz
04-07-2015, 08:42 PM
What type of switch is the old?

3 position Forward/Off/Reverse.


While we at it.. What's a NIB switch?

New In Box.


what kinda machine?

Ancient Taiwanese Mill/Drill, RF-30 type....'cept it isn't a Rong-Fu

The dials are in degrees of cubits...

Paul Pless
04-07-2015, 08:45 PM
mill/drill

sounds cool

seanz
04-07-2015, 08:53 PM
mill/drill

sounds cool

Done a couple of drilling tests on it, feels really solid. If I was you (or lived where you do) I'd have a small(ish) Bridgeport knee style mill, they cost at least twice as much as what I paid here for the mill/drill. A mill/drill looks smaller and logically easier to deal with...but you still need an engine crane to shift it.

Steve McMahon
04-07-2015, 09:20 PM
Not quite enough information for me to be able to help you. There are various types of single phase motors and few different ways to reverse them. I'm not an expert in all the variations but we have a few guys in our motor shop that are. If you can snap some pictures, a sketch or two etc. I'd be happy to chase down an answer for you. Sometimes the connection diagram for the motor will be on the inside of the junction box cover.

Paul Pless
04-07-2015, 09:24 PM
Done a couple of drilling tests on it, feels really solid. If I was you (or lived where you do) I'd have a small(ish) Bridgeport knee style mill, they cost at least twice as much as what I paid here for the mill/drill. A mill/drill looks smaller and logically easier to deal with...but you still need an engine crane to shift it.

the tool deals here are pretty crazy, phenomenal deals on high quality equipment
i'm running out of space and i have enough trouble teaching myself woodworking much less metal working
but, i should move my welding equipment from alabama to here and perhaps buy a lathe

the_gr8t_waldo
04-07-2015, 09:59 PM
I've been pouring over my reference books, to no avail. could you take a pic or three of the motor leads, switch interior? ...NIB...that's a new one on me! ( you didn't do anything crazy like take it OUT of the box, did you?)

Syed
04-08-2015, 01:05 AM
Sean, is your diagram like this?

http://www.learningaboutelectronics.com/images/DPDT-toggle-switch-diagram.png

pila
04-08-2015, 01:22 AM
Three leg three-phase...reverse any two wires to reverse motor rotation...single phase, reverse the start winding leads...
Taiwan copy of a Bridgeport ?? I've run those as well as the Bridgeport. They are OK but sometimes not quite as accurate as the original.

seanz
04-08-2015, 04:43 AM
Sean, is your diagram like this?

http://www.learningaboutelectronics.com/images/DPDT-toggle-switch-diagram.png

It's not completely (I think) unlike that. This is inside of the switch cover now.

http://i225.photobucket.com/albums/dd164/seanz_2007/042_zpsln8jm5it.jpg


This is the best of three (gave up after three) pics of the wiring diagram from the NIB switch.

http://i225.photobucket.com/albums/dd164/seanz_2007/045_zpsygogrphf.jpg

At the top of the single phase diagram it says "loop terminals thus". That's fine, that just phase and neutral. Underneath (the motor side) it has "start", and under that "run".

But it would need to hook into this...

http://i225.photobucket.com/albums/dd164/seanz_2007/037_zpstuk8xo9r.jpg

That's 3 wires plus earth. So, whatever it's for, I don't think the NIB switch is suitable for this set-up.

seanz
04-08-2015, 04:47 AM
Three leg three-phase...reverse any two wires to reverse motor rotation...single phase, reverse the start winding leads...
Taiwan copy of a Bridgeport ?? I've run those as well as the Bridgeport. They are OK but sometimes not quite as accurate as the original.

Mid Michigan? You must trip over Bridgeports...:)

This is not a knee mill, smaller, but it's a drill-press on steroids. Has a mill table, belt driven and the head cranks up/down on a column.

Syed
04-08-2015, 04:50 AM
All aside, you like NIB. :D

seanz
04-08-2015, 04:56 AM
Hey, it's nice to have something new for a change.
:)

Also, when I'm talking about two things that use the same name (switch for instance) it's nice to be able to differentiate the two easily...just so at least I know which one I'm talking about.
;)

Steve McMahon
04-08-2015, 07:37 AM
Are there numbers on the motor leads at the junction box and / or are they colour coded?

the_gr8t_waldo
04-08-2015, 09:56 AM
Arrow hart no longer make that switch......they recommend their P64 switch. A cheaper alternative would be a drum switch. Wiring diagrams for the d.s. are easily found on line.

pila
04-08-2015, 01:42 PM
We don't trip over Bridgeports like some years ago. Many small job shops have disappeared, and they are the places that had rows of Bridgeports. Saginaw Steering is now owned by the Chinese Army, as most people know, and don't farm out the small jobs stuff like in the old days.....
GM doesn't have much here now, compared to the old days.

Stiletto
04-08-2015, 04:46 PM
Can you identify which wires are the start windings and which are the run windings? Reversal is achieved by swapping the wires to one, not both.

uphill.org.uk/pages/engineering/tips/tips_2.htm

Michael D. Storey
04-08-2015, 05:06 PM
On the outside of the motor, or on the inside of the metal cover there should be a small diagram that tells how to wire it to achieve the desired rotational direction. All with two power wires coming in. That will show you where to connect the wires to achieve the desired direction. The two powers, of course, go into your switch.
P.S. NIB is N to me, too

seanz
04-08-2015, 07:17 PM
Can you identify which wires are the start windings and which are the run windings? Reversal is achieved by swapping the wires to one, not both.

uphill.org.uk/pages/engineering/tips/tips_2.htm

You're a genius, cheers.
:)

The diagrams on that page are just what I needed. The first is as installed. The second looks a lot like the Arrow Hart switch. Sweet.


So, what I've got (plus an emergency stop) should bring the machine into the 21st C.


It's a little hard to find industrial electrics locally at the moment. When you go to a big supplier and ask about insulation for switches they say "Is it a metal framed house?" The machinery switch section of the shelves was a little sparse too. Building is flat out here right now. Which is another reason I'm trying to get things sorted (by asking annoying questions on the internet) before I get an electrician in. Don't want to waste their time, and, don't want to pay for the extra time either. :)

seanz
04-11-2015, 06:28 PM
Good view of the type of switch that's fitted now.

https://misterlinnsworkshop.wordpress.com/category/myford-ml7b/page/18/

Syed
04-12-2015, 12:25 AM
Happy ending! |:)

seanz
04-12-2015, 01:59 AM
Thanks for all of the answers.
:)

PeterSibley
04-12-2015, 02:48 AM
Mid Michigan? You must trip over Bridgeports...:)

This is not a knee mill, smaller, but it's a drill-press on steroids. Has a mill table, belt driven and the head cranks up/down on a column.

I have one of those, it's a great drill press and even mills !

seanz
04-12-2015, 02:55 AM
Yep, just did its first little milling job...milling out the slots on the milling vise from 7/16" to 1/2". Interesting bit of workholding.
:)

PeterSibley
04-12-2015, 03:09 AM
I am an absolute numbie at milling, I always get my speeds wrong but have successfully milled bronze !!

Steel not so much .:o;)

seanz
04-12-2015, 04:02 AM
http://i225.photobucket.com/albums/dd164/seanz_2007/002_zpsewt9f5j7.jpg

It's primitive, but it works. First real job will be milling slots in a piece of aluminium for a new table saw fence.

PeterSibley
04-12-2015, 05:11 AM
This my model http://www.machineryhouse.com.au/K012, I bought it new for about $1200.
http://images.machineryhouse.com.au/products/K012/700/11_Left-View.jpg

seanz
04-12-2015, 05:20 AM
Oooh, how refined.

:)

PeterSibley
04-12-2015, 05:31 AM
Yep, that's me .:d