Rusty Mill

Apparently they are going to hold this as a live auction too. So when you bid on the web you may still be beaten on live auction day by a "real person" :grin:

I would love to go to that auction. Did anyone notice that they have a bunch of these 75HP 3 phase pumps starting at $25 opening bid?

https://sierra.proxibid.com/Industr...urora-Pump-with-Motor/lotInformation/46923610

It's hard to believe that these would really be 75HP. But if they are imagine the Rotary Phase Converter you could build with one of those motors!

You could use that to drive anything.

It must be a misprint? Surely they are only 7.5 HP. Even that wouldn't be bad if you could get them for $25. I'd buy 3 or 4 of those at $25 each if I could. They would make great rotary phase converters. Surely they aren't actually 75HP. That would be unreal.

They have tons and tons of 3 phase motors at that auction. I'm sure a person who wants to build a rotary phase converter could find some gold there.

I was looking for a 7.5 HP 3-phase motor to use and the cheapest used one I could find was $99. Like I say, at $25 I'd buy 3 or 4 of them.
 
JimDawson said:
Those motor are really 75 HP, 175 amps at 230V. A little big for most home shops o_O
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Ok, probably don't want those then. :grin:

Although as rotary phase converters they most likely simply wouldn't generate that kind of power.

But you're right. None the less, with the tons of 3-phase motors they do have in various lots in that auction you probably could find some suitable motors to use as a 3-phase rotary idler motor. For my purposes I'm thinking 7.5 HP would probably work. Although something slightly bigger would probably be better. Maybe 10 HP.

In a rotary phase convertor the idler motor needs to be about 3 times larger than the motors you want to run. So if you want to run a 3 HP motor you need a 10 HP idler motor. Although I've heard of people running a 3 HP motor with rotary phase converters that only had 7.5 HP idlers. They still work, they just wouldn't be as strong.

I've been thinking of building a 3-phase rotary converter to run 2 HP 3-phase motors. So a 7.5 HP motor should work well. In fact, some people have told me that I could get by with a 5 HP idler. It just wouldn't deliver as much power as a 7.5 HP would.

Anyway. I'm sure I could find something there that would work. Problem is that the auction is too far away. I live in PA. They don't ship anyway, and even if they did the shipping costs would destroy the original deal. Nothing saved in the end.

But yeah, someone could find a great deal on some 3 phase motors there. Assuming you could get them for the starting bid or very close to it.
 
Robo_Pi said:
In a rotary phase convertor the idler motor needs to be about 3 times larger than the motors you want to run. So if you want to run a 3 HP motor you need a 10 HP idler motor.
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I'm running my 10HP lathe on a 15HP RPC. 1.5 to 2X is all you really need. It handles a 150% intermittent load with some growling. Having said that, I do have a 2HP hydraulic pump on that circuit also that is always on when the spindle motor runs, so that adds to the RPC starting power. Anyway that system runs the 10HP spindle on a VFD, four 1.8 KW servos, two coolant pumps, and the hydraulic pump.
 
I agree. The approximate 3 time larger is the theoretical ratio often given in theory books. And I believe that number is actually given to account for other losses in a typical system. But as a practical matter you can actually get by with far less.

In any case, whatever size motor a person might need they might be able to find one at this auction at a pretty decent price. I'd be happy to get anything from 5 to 10 HP for $25. And it appears that some of those lots include far more than one motor. So you might be getting the motors for only a few bucks each in come cases. Assuming those opening bid prices don't go up much. That might be the case since there typically aren't a lot of people looking for 3-phase motors. So this is a chance to get a bunch cheap. For someone who actually wants them.

I wouldn't mind having a bunch of cheap 3-phase motors to play around with. :grin:

If nothing else I'd have fun experimenting with them. I'd definitely go to that auction and pick some up if there wan't any serious bidding competition. I'm not going to pay a lot of money for them. But if I can get them for close to that $25 starting bid, I'd pick some up. Especially if they are being sold in lots.


Here's a 3-phase 10 HP starting bid $25

5217.jpg


Here's a lot of 23 motors starting at $25. Some of these might even be 110-220v single phase. That's almost a buck a piece. I'd grab up on those for that price.

5227.jpg


Here's 3 big ones. Sold as a lot starting at $25.

5228.jpg


With my luck if I went to this auction there would be a bunch of other people wanting these motors too. :grin:

For $25 a lot I'd love to have these. But if I had to pay much more than that I wouldn't want them. So it all depends on how many people show up who would want these motors. If I lived close by I'd bid on all three of these lots at the starting bid, and just see if I win. If so, I'd go get them. If not, nothing lost.
 
View it! spend ten minutes going over it, then walk away and look at other stuff. Then go back and give it another ten minutes, and if you get chance, do it again. If the machine is basically good, dont worry about the rust, it will clean off easy. I buy machines like this(or used to, retired now) all the time, for pennies, spend a few days on them, and sell for thousands, and have equipped my worksop with a range of pristine machine tools for very little money. If there is a serious problem on it, you won't spot it first time you look! in many years of auction buying I have never regretted a purchase, only the ones I didnt buy! Transport is the bugbear, I was limited to 2 (english) tons!
 
I'd go 300 on that mill, if I needed one. It would need complete dissasembly, de rusting and repairs made to all the stuff you can't tell is messed up till you get it apart. As long as the ways are not pitted, the surface rust will come off with some phosphoric acid and scrubbing. If it belonged to a public works, you can bet it didn't get much use, so wear probably won't be a problem.
 
hermetic said:
View it! spend ten minutes going over it, then walk away and look at other stuff. Then go back and give it another ten minutes, and if you get chance, do it again. If the machine is basically good, dont worry about the rust, it will clean off easy. I buy machines like this(or used to, retired now) all the time, for pennies, spend a few days on them, and sell for thousands, and have equipped my worksop with a range of pristine machine tools for very little money. If there is a serious problem on it, you won't spot it first time you look! in many years of auction buying I have never regretted a purchase, only the ones I didnt buy! Transport is the bugbear, I was limited to 2 (english) tons!
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You didn't answer the question of the OP. What would it be worth?

What would be your max bid? (assume no major problems other than the rust). You've looked it over well many times. And found nothing major save for the rust issue. At what point in the auction would you walk away?

I offered $400. You you bid over that? Or would you have already walked away earlier when the bidding was still lower?

Just curious whether I would have won this mill at $400 if you and I were the only two bidders. :grin:

If you were willing to go $405 I'd be the one going home without the mill.
 
cjtoombs said:
I'd go 300 on that mill, if I needed one. It would need complete dissasembly, de rusting and repairs made to all the stuff you can't tell is messed up till you get it apart. As long as the ways are not pitted, the surface rust will come off with some phosphoric acid and scrubbing. If it belonged to a public works, you can bet it didn't get much use, so wear probably won't be a problem.
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I already bid $400 in an eariler post (hypothetically of course) So if you and I were the only people bidding on the mill I would have won it for $305. :grin: $95 less than I was willing to pay.

I'm not going to bid on this mill in reality because it's too far away from me. I live in PA and the mill is in AZ. So I won't be bidding on this mill for real. But if this auction where just down the street from me I'd head over there with $400 in my pocket. :grin:

I hope I get to see what the thing actually goes for in real life.

Anyone bidding $405 for it?
 
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