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Gear driven power feed motor

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Dynahoe Dave

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Hi,
does anyone have the old gear driven power feed? It has a Master 1/8HP 203 / 230 V single phase motor.
Mine is drawing around 4 amps @ 240V running with no load, which seems really high for such a low power motor. Almost 1000Watts!
The starting winding gets a pulse initially, and drops to zero, so it's not stuck on. The starting cap also only has current during the spin up.
I have had no luck searching for anything related to the motor, even the frame number 5217 seems to be so old school nothing comes up.

It seems to run ok, but it does get pretty hot after a short while, - which I would expect with close to 1KW going into it...

The nameplate has a current rating, but it is damaged right near the number, so I am not certain what it is. It could be anything - X.7 amps.

Can anyone read their nameplate and or measure the current?
 

mksj

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If you calculate that an ideal motor is 750W/Hp, you come up with ~100W or 0.42A at 240VAC, given an efficiency for a single phase motor of around 60% you would end up with 0.7A. If you have a local motor shop, probably worth having them take a look at it.
 

Dynahoe Dave

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That makes sense. I'll have to remove it and look it over. I was trying to figure how to confirm my suspicion that something is way wrong, but just wasn't getting to the basic 750w/ hp thing.
 

Dynahoe Dave

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Oooh! It's possible the start and run windings are swapped . The wiring on this machine was pretty sketchy.
 

Dynahoe Dave

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So far , so weird.... Took the end off, nothing looks burned up or damaged. Bearings nice and free, no binding.
Run winding seems happy with much less than 240V The start winding is the start winding, they don't seem to have been swapped.
 

Dynahoe Dave

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Did a bunch more testing and experiments, it doesn't seem like I have the wiring wrong. It just draws way too much current. Bearings are good, and most of the testing today was with it removed from the gearbox, so there was absolutely no mechanical load on the motor.
For now, I wired it up with a transformer to drop the voltage to 180V. It draws around 2 amps that way, so won't go up in smoke... I'm thinking that it's going to be difficult to find a good one of these motors, since even H&W doesn't support them.
I'm sure I could get it rewound, but $. I also have seen aftermarket power feed drives...
 

Kilroy08

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Oct 7, 2018
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Sounds like a problem in the windings. If there's an internal short, I.E. the laquer on the windings having flaked off somewhere, the motor will run; however, it will draw excessive current and overheat.

I have the same gearbox power feed on my Bridgeport. Only difference is mine came with a 3 phase 1/8 horse motor. The face mount is Bridgeport specific. As is the output shaft. Which as fate would have it is the armature shaft, as well. With adapting a different motor to the box being not impossible, but extra work, I decided to see if I could fix what I had.

My problem was that the idiots that owned it before me put regular gear oil in and over filled it. The front seal failed and the windings got soaked. I got lucky and was able to soak the motor in my then new parts washer to leach out all the oil. Then I let it sit for a few weeks to dry out. (I run 50/50 odorless mineral spirits and clear K1 kerosene in my tank) I put a new seal in the face of the motor and carefullishly picked the shields off of the bearings and re greased them. Got a second VFD for cheap to run the power feed and I was back in business. The seal was an oddball size. If memory serves correctly, I ended up getting an input shaft seal for an '80s Mazda or Nissan pickup manual transmission that fit perfectly. I think I spent somewhere around a week scouring various seal catalogs before I found something close and gave it a shot. Why the heck a 1960s American made electric motor took a metric sized seal is beyond me.

Crossing lubes over to what's on the market today, I ended up running Mobil DTE 26 in the gearbox. I also got a roll of one of the better grades of Felpro gasket sheet and made new gaskets for the motor face and side cover.
 

Kilroy08

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Well, I had a chance to actually use the power feed for serious work. I had forgotten that the story I was told when I bought my mill was that some knuckledragger left the power feed engaged, walked away, and the machine crashed. Well, being bound up and stalled, the windings got cooked. I could fry bacon on the motor housing!

I'll make some notes when I go to adapt another motor to the gearbox in a couple weeks and share what I came up with. I'll probably press out the armature shaft and make a sleeve to fit an output shaft. The sleeve will get welded to the armature stub and pinned to the new motors output shaft so it doesn't get pulled off under load.
 
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