Rockwell 46-450 Lathe Wiring Questions

[Michael Kroart]

Hello,

My Rockwell 46-450 lathe has resurfaced from 10 years of storage and I'm just now getting into an electrical problem that existed back then. I used the lathe for a couple months after purchase from a high school (1999) without any issues, but then it started turning off when I made heavier cuts. After a while I couldn't get it to start without a little help from my left hand. Eventually all I could get was a sharp rapping noise from the junction box located inside the stand - the noise came from what I believe to be the magnetic motor starter. When I exposed it and tried again I noticed sparks coming from the contacts in that unit.

The lathe is wired for 110/1 phase (at least that's how I've been able to use it). Other than than, I've posted pics of the major components in the hopes some one might have a theory as to what's going on and what may need to be replaced. I did remove and clean the contacts from the magnetic motor starter, but to no avail.

It was stored in a fairly damp basement over that period, and was urinated on by at least 1 cat...but I doubt the cat reached the wiring or motor.

I have now removed all wiring and components from the lathe and have them in a pile. I may drop off all the components to a motor repair shop at some point, but I'd appreciate any theories or suggestions for cost-effective repairs.

Main component specs

Motor Starter(?): Furnas, 42BD35AJ
Bimetal Overload Relay: 48DA17A, 600VAC Max, Non-Ambient Compensated
??? Brown paper/metal housing: Basler Electric, BE12120002, 24V 55VA
??? Small Yellow Coil/Contact: 10 A, 120VAC 1PH

The upside down switch near the pulleys is activated by the speed control shaft; switch is activated at 340 RPM (min speed).

Thanks for your time,

Mike

[Dennis Ford]

To narrow down the possible source of problems, try wiring the motor directly to a cord with a plug on the other end. With the belt removed and the motor secured, plug in the cord. If the motor runs, you can begin working on the starter and wiring.

Since you saw sparks coming from the starter contacts, it definitely has problems. It would probably be better to replace it, but a good cleaning and some careful filing of the contacts might make it serviceable.

Check over all the connections carefully, a bad connection could have caused all the problems.

[Michael Kroart]

Dennis - thanks for the suggestion.

The wires coming from the motor are tagged with the numbers 1,2,3,4,5, and 8. Currently they're grouped 1,3,8 and 2,4,5 to two leads respectively. (photo of groupings attached)

Any suggestions for which of these to use for testing?

Mike

[Dennis Ford]

Your motor has a wiring diagram on it (the red section on the left is for 115v). I can not read the wire numbers in the picture but it does show two groups of three wires. Connect one group to the black wire of test cord, one group to the white wire and connect the ground to the motor frame.

The controls for this machine seem overly complicated, most machines this size do not have an overload relay. I do not understand the "speed switch", does it prevent the motor from starting until the speed control is moved to minimum speed? If this was my machine, I would simplify the controls.

[Tom Baugues]

Michael, I have this lathe myself. Actually mine is the 46-451 model but they are the same. I do not have all of those starters and such. Mine is simply wired to the motor and on/off switch with a cord coming out and plug at the end. As Dennis has mentioned you might want to try to simplify all of that. These were designed to run on either 3 phase 240 volt or single phase 120 volt. I have read that alot of people want to keep using the 3 phase system but my garage does not have 220 power so 110 volts works well for me.

Tom

[Steve Bistritz]

Thought i would weigh in, have the same lathe but mine is set up for three phase on a VFD and all controls are 24 volt. A 110 motor can run just with an on/ off switch like stated above. If you can swing the price of the VFD you can have infinite speed dialing. on/off switch and forward/ reverse. You get spoiled really fast. Simplify for now just to see how healthy the motor is and go from there.

[Michael Kroart]

Thanks for your responses.

I came across a wiring manual for 1968 Rockwell factory wired 12 inch wood lathes (4 pages attached). None of the schematics match my setup exactly but there are similarities:

Page 5: Push Button Switch and Magnetic Starter with Full Voltage Control for Single Phase Motors (this one seems the closest)

Page 2: Push Button Manual Switch Control for Single Phase Motors (this would match suggested workarounds from previous posts)

Page 6: this schematic is for a 3 phase motor, but shows the heater coil (my heater coil appears to be a separate component from the relay, as shown in pics)

Page 7: this schematic is also for 3 phase, but includes a 24V transformer; looks like this would only be required for 230, 460, 208 and 575 volt setup.

As far as the "speed switch" - my guess is it acts as a remote shutoff for the motor. I don't remember whether the machine actually cut off or not when the handle was moved to the lowest rpm setting (it was 10 years ago). Is it possible that this speed switch/remote cutoff control is only only supported when a 3 phase magnetic starter and peripherals are installed?

I read somewhere else that older motors may not include thermal protection- that this feature may require addition of a matched overload overload component. Doesthis ring a bell to anyone?

I'll wire and test the motor as suggested by Dennis and post results. If the "speed switch" does function as described above, I may hold off on rewiring in order to see what the costs are to repair the existing setup.

Thanks,

Mike

[Michael Kroart]

The "speed switch" (for lack of a better term) was the culprit. We tested all connections with a meter, and noticed no voltage was passing through the switch - then clicked it a few times and freed up the mechanical parts. For whatever reason the switch appears to have been stuck but now works correctly. I wired the motor independently the circuitry and it runs fine.

In removing the wiring I also removed the reeves drive, which was nearly locked up and could have contributed to an overload and activation of the relay control.

Thank you all for your suggestions.

[Michael Kroart]

I found a .pdf parts beakdown for the hardware I previously referred to as a "speed switch". This was an optional feature referred to as a "Slow Start Option". I assume it was designed to permit lathe startup only at low RPM.

I attached the manual for anyone who's interested.