Electric motor reversing theory in practice.

Ultradog MN

Well-known Member
Location
Twin Cities
I didn't want to hijack Olit's thread below.
I mentioned that I picked up an old Leblond engine lathe here recently.
The original reversing drum switch on it was smashed and unuseable.
It has this tag on the motor.

cvphoto57385.jpg


I ordered the drum switch below but wiring it is above my pay grade and I can't find an electrical contractor who's even interested in looking at it.
"Nope. We don't do machinery or appliances."
Or "Nope, that's industrial. We'll give you new electrical service in your house or garage tho."
Now what do I do?
Is this something that someone here could talk me through?
I did install a new meter socket on my house and ran underground for new 100A panel in garage a year ago. All was inspected and passed. So I can do a little wiring...




cvphoto57386.jpg


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Use the Split phase diagram.
120V place the main windings in parallel . 240v operation Place the main windings in series .
Start Winding is 120V so it must use the centre point between the run windings .
 
(quoted from post at 03:11:29 09/27/20) I didn't want to hijack Olit's thread below.
I mentioned that I picked up an old Leblond engine lathe here recently.
The original reversing drum switch on it was smashed and unuseable.
It has this tag on the motor.

<img src="https://www.yesterdaystractors.com/cvphotos/cvphoto57385.jpg">

I ordered the drum switch below but wiring it is above my pay grade and I can't find an electrical contractor who's even interested in looking at it.
"Nope. We don't do machinery or appliances."
Or "Nope, that's industrial. We'll give you new electrical service in your house or garage tho."
Now what do I do?
Is this something that someone here could talk me through?
I did install a new meter socket on my house and ran underground for new 100A panel in garage a year ago. All was inspected and passed. So I can do a little wiring...




<img src="https://www.yesterdaystractors.com/cvphotos/cvphoto57386.jpg">

<img src="https://www.yesterdaystractors.com/cvphotos/cvphoto57387.jpg">

<img src="https://www.yesterdaystractors.com/cvphotos/cvphoto57388.jpg">
nswer (as if other way around), if it was mine I would $h1t can the junk and buy a nice new one. :)
 

120 or 240 v ?
Need an ohm meter to find the two low resistance run windings and the one high resistance start winding/starter switch .
 
Doubt I could ever afford a new one.
Not interested in a China made like a
Grizzly or some such.
A "real" lathe new would cost you $50K+.
Going to have to approach this like I did
tractors.
Started with a 2N and worked my way up to
a couple of 4000s and a 3000.
They're not new but they're "modern" in
some ways.
This old 1 HP Leblond is modern in some
ways.
It's a gear head as opposed to the old
flat belt machines like the South Bends
etc. Also has seperate lead screw and
feed rod which is better than the SBs.
Kinda like starting out with a Jubilee
which at least has live hydraulics.
Ancient yes but still better than an N.
Maybe I can work my way up to a 1960s
Sheldon or another Leblond. 5 hp,
tighter, better, faster. Get the
equivalent of PS and live pto on it.
This one Is a nice size. 14"X30"
 
I just wired in a 220V outlet for it to
match what was on the cord.
I can check/verify inside the weatherhead
for that at least.
I don't think I'll learn this stuff but
thanks for trying.
I do have a bit of exposure to motors but
not the electrical end of them.
My last 1 1/2 years in the Navy I was the
machinest in a motor rewind shop.
Stubbed a lot of shafts, turned and
undercut commutators, balanced rotors and
fans, line bored new bushings in motor
housings, repaired keyways, etc.
I purposly didn't learn the electrical
end of them. If I had I would have had to
stand main switchboard watches while at
sea. Being the dumb, non qual machinest
in an electrical division was a way to
get out of those dreary underway watches.
 
Here is my solution. The folks can critique it and say yah or I am all wet.
I don't recommend using it to start and stop the motor. Use a motor rated switch.

cvphoto57475.jpg
 
Hi again UD,
Here is one way to do it. I added a 2 pole switch to the main power wires because I don't know how your motor is wound without an ohm meter test between the black to blue wires (with nothing else connected). The first one shows the wires connected and switches OFF. The other 2 show the switch internal connections in the Forward and Reverse positions. It is a pretty quick and crude diagram but hopefully it makes some sense.
Carl
mvphoto62455.jpg


mvphoto62456.jpg


mvphoto62457.jpg
 
Ray, Carl,
Thank you both!
I believe I could follow those diagrams.
Carls70, tell me more about this,
"an ohm meter test between the black to blue wires (with nothing else connected)."
I could do that.
Would rather not have a second switch.
Was kinda hoping I could do it like the old one was by throwing the handle one way or the other and have it go.
Is this switch not heavy enough to handle the starting current?
I would look at a heavier drum switch rather than have two switches.
 
I'm not an electrician or an engineer but it looked to me like according to the motor plate that the current path of the RUN windings in the motor might be powered all the time in the 240V diagram if the there wasn't a break in the circuit between the black and blue. I could be mistaken on this but that was my logic with the second switch.

I would take an ohms reading when the meter is connected between the BLACK and BLUE motor wires (with the RED, GREEN, ORANGE and TRACER wires disconnected from each other). If there is no ohms reading (infinite / open circuit) then you shouldn't need the main switch at all. If there IS an ohms reading then I would recommend a different switch so you aren't leaving one of the windings energized all the time... Just thinking out loud here...

Carl
 
You can use this switch Square D Class 2601, Type BG-1, Series B. It has a center OFF and is HP rated for 3 hp at 240 volts.

cvphoto57528.jpg
 
Forgot to add one line L1 will always be hot to the motor.
Hope you have a master switch to turn off the circuit(s) before you do any maintenance.
 
Thanks.
My neighbor's friend is a industrial robotics teacher at a VoTech here. I will wire it but he's going to stop by and check my work. The lathe does have have disconnects. I ran a new 220v 15a circuit from the panel and it has a fused knife switch mounted on the back of the machine. Or just pull the plug...

cvphoto57623.jpg
 

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