Pratt & Whitney 3C Bench Miller wiring diagram

[Vintagetechnic]

Does anyone out there have a wiring diagram for a Pratt & Whitney 3C Bench Miller? It happened that I had to move one of these cute little mills through a cellar doorway that was 28" wide, I was forced to separate the mill from the lower bench assembly. Although I tagged all the wires going up to the rotary switch on the side of the column, in separating the components, I wiped most of the numbers off the tags. So now I can't get the Master Speedranger operational. Can anyone help me?

 

[jim rozen]

My 3C came without the switch but there's one member here with an original speed-ranger setup, so I hope he sees the thread. Your motor is 240 volt two speed consequent pole and has six wires. The connections are basically six taps along a ring, with equal resistance windings between each tap. If you measure carefully from one lead to the other 5, you will find 3 distinct resistance values. Two will be the same, two will be the same but higher, and one will be higher yet, the highest. You'll need an ohm-meter that has about two decimal places to do this well.

 

[morsetaper2]

Bill,

When I moved my P&W 3C mill I made some sketches and took some photos of that rotary switch... I think?

I'll have to search around on my old computer to see what I have. Can't say it's what you need, but its all I can offer.

Mark Long

 

[morsetaper2]

I found some pics of my notations on the drum switch connections. But I gather from what you wrote your tags on the wires themselves are now missing?

 

[jim rozen]

MT2 - for the record, does that single switch in the 3C mill do both speed change and fwd/reverse change? Or is there a separate fwd/off/rev drum switch?

Thanks

 

[morsetaper2]

MT2 - for the record, does that single switch in the 3C mill do both speed change and fwd/reverse change? Or is there a separate fwd/off/rev drum switch?

Thanks

Jim, that switch just reverses the motor.

 

[morsetaper2]

Jim, The F/R switch also controls Hi or Low speed range. See the image.

 

[discodan]

I have a diagram of the wiring from material I got from someone on another forum. If you want to IM me your email I can send you everything I have. I cant post the picture here because of the format and even if I change format it still won't post. FYI, I have a war production 3C with hand-miller setup. And mine is powered by a variable speed Craftsman motor that has a speed dial right on the face. I have a full set of collets and a dividing head. I am missing an arbor and would love to find a vertical head.

Dan

 

[Vintagetechnic]

Bill,

When I moved my P&W 3C mill I made some sketches and took some photos of that rotary switch... I think?

I'll have to search around on my old computer to see what I have. Can't say it's what you need, but its all I can offer.

Mark Long

The motor leads are identified clearly. T1, T2, etc....T6. All I need now is which terminals on the rotary switch these leads are to be attached. I had hoped that somebody out there has an operators/owners manual that contains an image of the wiring such that I can put the wires on the proper terminals of the switch.
Bill Bonta

 

[discodan]

Bill, did you see my post? I think I may have what you need. I also see you are up near Hunt Valley. I am near Annapolis. Would love to see your 3C setup.

Dan

 

[morsetaper2]

The motor leads are identified clearly. T1, T2, etc....T6. All I need now is which terminals on the rotary switch these leads are to be attached. I had hoped that somebody out there has an operators/owners manual that contains an image of the wiring such that I can put the wires on the proper terminals of the switch.
Bill Bonta

If I understand you correctly, then the photos I placed in post #4 should be what you are looking for (hopefully).

 

[Vintagetechnic]

That might be just what I need. My email is [email protected]. FYI, if you are interested you can see a series of photos of my ols 3C on Lathes.co.uk. The one shown was my old machine. I loved working with it but upgraded for the powered feed on a Deckel FP1. The machine I moved is going into a clockmakers workshop. It too has a vertical head, a full set of collets, the P&W latchplate indexing head and the right angle table extension. Lots of gears ahead.
Thanks.......Bill

 

[Vintagetechnic]

Diamond:
Yes, the tags at the switch are now missing. I screwed up. Paper masking tape for the tags got wiped in the disassembly process.

Bill

 

[jim rozen]

Thanks for the close-up of the switch setup. My machine was missing that plate, it's been replaced with a toggle switch and a speed control knob for the VFD.

 

[SteveM]

Here's the original wiring diagram



Steve

 

[morsetaper2]

Here's the original wiring diagram

View attachment 340032

Steve

Steve, any chance you could provide that in a larger pdf size?

Thanks, MT2

 

[Vintagetechnic]

Bill, did you see my post? I think I may have what you need. I also see you are up near Hunt Valley. I am near Annapolis. Would love to see your 3C setup.

Dan

:

Maybe you do have what I want. Please call me on 410-666-3842
Regards.............Bill

 

[Vintagetechnic]

Everybody: Many thanks to all for the info. I got the exact diagram that I was looking for from discodan and SteveM. Please forgive my clumsy communication on this thread. At 83 yrs old I find it difficult to deal with the modern digital world.
Regards..........Bill Bonta

 

[jim rozen]

Everybody: Many thanks to all for the info. I got the exact diagram that I was looking for from discodan and SteveM. Please forgive my clumsy communication on this thread. At 83 yrs old I find it difficult to deal with the modern digital world.
Regards..........Bill Bonta

Not for nothing, but for an 83 year young fellow you seen to be managing just fine with this new-fangled internet stuff. Good luck on the P&W machine!

 

[SteveM]

Bill Bonta

Hey, didn't you used to own the P&W mill on Tony Griffith's website?

Steve