GAWWWW-LEEEEE youse guys!!! I JUST got done writing up the text for what I was going to start as a new thread here, regarding that very same Dayton drum switch and a 230 volt reversing motor. And here ya done got it started already!!!
Anyway, the following is the ORIGINAL text and photos I was about to post. It's posed as a question, because I'm not
absolutely sure my "new" solution is valid. If it sounds like it's just a slight bit off-topic, my apologies. I'm just a bit too lazy to re-write the whole durn thing:
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About a month ago I bought a vintage (1990) Grizzly DF1224G/G1003 12x24 lathe. As purchased, it would run OK in reverse but only buzz when switched to forward. When I got it home I checked the existing drum-type switch, and it just about fell apart in my hands. The 2HP motor had been wired for 115 volts, which spec’d out at 18 amps - no wonder the switch was toast!
I bought a new Dayton 2X440 drum switch and started puzzling out how to wire it. The data plate inside the motor, as well as what diagrams I could find in the manual, called for connecting the two run coils (motor wires 1-3 and 2-4) in series, and connecting the start coil (motor wires 5-6) between the common point (2&3) and L2. To reverse the motor, the 5-6 leads are interchanged. The photo (thanks to Chris, aka Shadowdog500) shows a similar (3/4HP) motor’s connection data plate.
View attachment 82189
Unfortunately, the above scheme requires 6 conductors between the motor and the switch enclosure (1, 2-3, 4, 5, 6, and ground). Six conductor cables are about as easy to find as hen’s teeth! In addition, because the Dayton switch has only 6 contacts, there’s no choice but to leave L1 connected to the motor at all times! Yes, I did mount a local service disconnect ... but nevertheless, leaving a motor connected to a live wire gives me the willies. See schematic below.
View attachment 82190
Recently I found another Grizzly 12x24 lathe manual to download, and it had what I *think* is a viable alternative. The idea is to permanently wire one end of the start winding (5) to the common point between the run windings (2-3), then switch the other end of the start winding (6) between L1 and L2.
In theory, the common point (2-3-5) will be at neutral potential, so the start winding, whose other end is switched to either L1 or L2, will always be seeing just a nominal 115 volts (then go to zero when the centrifugal switch kicks out).
The nice thing about this scheme is that (1) it only requires 4 conductors between the motor and switch box, and (2) BOTH L1 and L2 are safely disconnected when the switch is set to the center position.
View attachment 82191
My question for any motor electricians here is: Am I OK on this? What might I be missing?
PS - The data sheet that came with the Dayton drum switch was absolutely no joy. Note that both of the schematics for “Single Phase” and “Induct. Repulsion” indicate a continuous connection between one side of the power line and the motor.
View attachment 82192
Thanks!