[How do I?] How to change gearbox speed on Gorton 9J?

TheSerialHobbyist said:
Yes, electrical has been a big challenge that I'm still working through.

I actually don't have 240V in my shop currently, but may end up running it. The big problem is that the original motor requires 440V, which introduces an additional headache.

I've been working through this and my current plan is:

1. replace the spindle motor with a big treadmill motor (DC, fed by regular 120V AC). There are several disadvantages to that, but the advantages are speed control, cost, and not needing to run 240V power.
2. the quill down feed motor is actually DC and already has a rectifier, so I can feed it 120V AC.
3. the table power feed motor is 220V AC. I can get a VFD that both converts single-phase to three-phase and also boosts that from 120V to 220V.

There is a good chance that the treadmill motor won't be adequate. The one I ordered is 2HP at 2400 RPM, which is significantly less torque than the original beast of a motor. If this motor isn't up to the task, then I'll need to run 240V and likely get a VFD that pushes that up to 440V (in addition to the phase conversion). But that VFD alone is about $500, which is why I'm trying the cheap solution first.
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Okay,

My first step would definitely be running a 30 or 40 amp circuit to the garage, you'll need it eventually in this hobby.

Next would be to contact a local motor shop if you have one and see if they can rewind the motor you have. Adapting any other motor will be a challenge and you're almost certainly going to need a mill and a lathe to make that happen.

Converting from 240v to 440v will require a step up transformer. They're out there, but unless you find one used and cheap you'll be into it for more than buying a different mill.

If you do really want to adapt to another motor I'd still go with a 240v three phase as they are relatively cheap used and easy to power. I have a 5hp I'd give you that I bought for $50 but you'd have to get it over to where you are. I used to live in Mesa btw.

Don't know where you ordered the treadmill motor or how much it cost but if it doesn't come with a suitable DC drive you'll be significant money into one of those unless you can build it yourself.

Honestly, I'd get the spindle drive situation figured out before spending anything more on this machine. It could be great, or turn out to be a pig in a poke.

John
 
Oh, post a picture of the motor plate so we can see if it could just be rewired to 240v
 
Yep, that's pretty much the exact same advice I've received elsewhere, haha. You are almost certainly correct, but I want to give the treadmill motor a shot. I'm good with electronics and have a plan on how to run it and mount it. If it doesn't have enough grunt (very likely), then I'll just use the motor for another project.

I very well might take you up on that motor! Says you're in Santa Cruz? Might be worth a drive from Phoenix for an awesome motor like that!

I've attached a photo of the motor plate. I'm pretty sure it can only run on 440V as-is. Any idea what kind of cost I'd be looking at to have it rewound? I figured it would be prohibitively expensive, but maybe I'm wrong.
 

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No idea how much a rewind would cost, probably too much but a motor shop could tell you if it’s just a matter of changing leads or needs a complete rebuild.

Here’s the motor I have.

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John
 
matthewsx said:
No idea how much a rewind would cost, probably too much but a motor shop could tell you if it’s just a matter of changing leads or needs a complete rebuild.

Here’s the motor I have.



John
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Looks like a great motor! If this DC motor doesn't work out (chances are good it won't), maybe I can talk my wife into a weekend trip to Santa Cruz as an excuse to pick it up, haha.
 
TheSerialHobbyist said:
Looks like a great motor! If this DC motor doesn't work out (chances are good it won't), maybe I can talk my wife into a weekend trip to Santa Cruz as an excuse to pick it up, haha.
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Would love to meet you, Santa Cruz is a nice place to visit anytime. Most of the wharf is still there. ;)
 
The end that fell in was already closed and under construction. Fortunately the three people that were on that section were quickly rescued. Our family friends memorial bench was swept away unfortunately.

The wharf at Capitola (just south of Santa Cruz) that was destroyed last year has been completely rebuilt. There lots of pilings along the coast from destroyed piers and wharfs you can see at low tide.

John
 
matthewsx said:
The end that fell in was already closed and under construction. Fortunately the three people that were on that section were quickly rescued. Our family friends memorial bench was swept away unfortunately.

The wharf at Capitola (just south of Santa Cruz) that was destroyed last year has been completely rebuilt. There lots of pilings along the coast from destroyed piers and wharfs you can see at low tide.

John
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Geez, sorry that happened to the bench, but at least nobody lost their life when it fell!
 
It looks like a two speed motor that is only wound for one voltage. If the current motor is good. A transformer to step up the voltage to 440 may be the easiest way to go. If you replace it with a single speed motor you will sacrifice the spindle speed range. Using a vfd on a two speed motor would be a challenge. What I did with my Hardinge lathe that has a two speed motor was to used a rotary phase converter. That way I could keep the existing wiring and controls and still have the range of spindle speed. The mill looks like it is worth the effort. Keep us updated on the progress. Thanks for the pictures
 
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