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Look what showed up at my shop door yesterday
- Thread starter olddude
- Start date
What ever company that is there, way to wasteful.
They must be making things for the government wasting our tax dollars.
Unfortunately there are too many gov contract companies like that.
But I'm sure they rite off there wast and don't really pay for it, we do !.
Yeah... I was gonna post that... beat me to it!
Probably better to not carry this much farther...
TPTB at this forum do not like political discussions... regardless of the truth in them.
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4GSR
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Nothing to do with the government or contractors.What ever company that is there, way to wasteful.
They must be making things for the government wasting our tax dollars
Unfortunately there are too many gov contract companies like that.
But I'm sure they rite off there wast and don't really pay for it, we do !.
I've seen this same thing happen with many industrial companies out there. The bean counters are the one's coming in and saying "Get rid of this and that!" It has to do with the IRS rules on inventory and equipment, and how it is controlled. Basically, your required to write off "X" amount of dead inventory, equipment, fixtures, and so on. And if you don't take advantage of this tax write off, you wind up getting taxed for this inventory! That's why you see this happen. I've seen high dollar parts made of Inconnel thrown into the dumpster, perfectly new tooling chunked out, out dated machines scrapped off and so on. It just part of Corporations doing business today! Ken
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You can run that motor on 50hz or 60hz. No problem there. The speed will just be a little different. Either about 600 RPM or 300 RPM difference depending on the pole count of the motor.
// Add about 20% to the labelled speeds, and if the motor says 415v or 230v, add about 20% to the 3-phase line voltage if you can (motors, most wound components, are "volts per Hertz", e.g. 400v 50Hz Vs 480v 60Hz, the motor current will be about the same)
A rotary phase converter uses a motor, caps and a few other little things to turn single phase into three phase, but the frequency in is the frequency out. If you have 60hz in you get 60hz out, and that determines the speed of your motor.
// A rotary is a good solution if you have a machine with more than one motor (e.g. a mill with separate spindle and feed motors, perhaps a coolant pump) or magnetic clutches/brakes, otherwise you'll need a VFD for each motor and to change the (probably high-power) transformer for the magnetics. You can also power other 3-phase equipment with it, and you're going to buy some (often cheaper than single-phase, as a lot of home shops wont have 3-phase!)
A VFD (depending on the model) can provide from a fraction of a cycle upto 1000hz. (maybe more?) They can be controlled by an external signal source, programming, or a simple POT depending on the features of that particular. Most 3phase motors at reasonable loads can be speed controlled by frequency from about half speed to about double speed with little or no ill affect. The problem at lower speeds is most motors have an internal fan for cooling that fails to move enough air when its turning slow.
// The more sophisticated / professional VFDs often let you configure one of their relay outputs to close below a certain frequency (may be called "supervisory frequency" in the menus) - I've used this to switch in a large (10") axial fan on the (open frame) motor, stays on until the motor's fed over 30Hz and can cool itself, stays on and cools the motor until I power the whole lathe off (the fan noise reminds me to...) at the isolator.
The motor simply may not have good enough bearings or be well enough balance for higher speeds. Sometimes you can overcome the heat dissipation issues of low speed operation by installing an external fan that continuously blows air through the motor at full speed regardless of spindle motor speed.
// see above
VFDs have the secondary benefit that at about 60-70% of their rating most can use a single phase input and produce a 3 phase output. There are just a few that are full rating with single phase input, but they will be advertised as such. If it doesn't say it then assume you need to derate it by about 30-40%.
// e.g. my 3HP lathe is fed by a vintage ABB 5HP inverter hacked to give 415v out from 240v in - simple mod, invalidates all the warranties and approvals, I'm pretty sure it's what one company in the UK does in the process of making theirs do the same and charging twice the price for it
For example: On my Hurco KMB1 it runs from 96 RPM at 3hz to 3600 RPM at 120hz. Its controlled by a VFD that uses a 0-10VDC signal from the CNC controller. The motor actually originally came as two motors. Inside the case of the motor is a second motor that just drives a fan. On my little high speed mills they have spindles that turn upto 24,000 RPM at 400hz. I am running single phase input to the VFD.
An aside note: Often on small to medium size drill presses guys switch out the single phase motor for a 3 phase motor with a VFD that is either POT controlled or front panel programming controlled so that they can vary speed more easily with fewer belt changes.
// it does, however, lose the torque multiplication that the belt provides at low speeds, I worked for an importer of Chinese drills (painted green...) which had no gearing to speak of and wouldn't push a drill through materials if it was as big as the chuck would take! For a pricey and apparently "industrial" drill it was very light duty...
Interesting factoid: Upto about 1HP there are some name brand VFDs that will also allow you tun run 230V motors with a single phase 120V input. There are some Chinese VFDs that claim to be able to handle higher HP in this circumstance, but I don't trust them.
Dave H. (the other one)
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- May 4, 2015
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How did anybody live without them in the fortys with a war looming big industry taking off wow . They must have done it all wrong. Now you throw all the best machines ever made cause some lunkhead thinks his cut from the sales is best for the company.
Bingo!! You sir are the winner of the debate.....good job! No politics here just the way business is done today. Actually, in this case a little gubment was involved. It's known as OSHA, hey come in to a plant and anything they don't like the looks of they tell you (they don't 'ask' you nicely) to either fix it the way they want you to or get it off the floor before their next visit or face thousands of dollars in fines.
This machine they said needed a couple of guards on the spindle and table slides. They checked on it and the cost was too high to justify it being done so they scrapped it. At one time they had another warehouse that stuff like this went to and about once a year they would auction this stuff off but it always cost more to do this than it was worth. Warehousing was bad enough but once you throw in labor to move this stuff around, inventory it, track it then pay a auction company to come in and auction it off they figured it out that they come out better just getting paid for the scrap. Once the decision is made it's simple, a $15.00 an hour man drives up to it with a folk truck and drops it in the dumpster. Fifteen minutes later it's done, what's that.... like about $3.50 then they wait for the scrap truck to come and get a check at the end of the month.
This company builds very expensive parts that are shipped all over the world and when the estimate is made on a piece of equipment everything is added in to the estimate. Parts, labor, freight, time, engineering and I'm sure a few other things are thrown into the pile then on top of that then they add in a plus or minus figure is added in. They get paid once the estimate is approved before the first nut or bolt is ordered. They have a lead time in the contract and they never miss this time frame and most of the time they ship it weeks before it is due. If a part or piece of material comes in to the loading dock with a scratch on it no matter how small it gets scrapped and who ever sent it in gets hit with the bill for a new one. That's how I ended up with those 316L stainless beams and box tube; about $1400.00 worth of material as the pallet it was on was had been bumped and part of the pallet was crushed. They had another load was at the dock the next morning and this stuff was headed to the scrap bin. My trailer just happened to be in the hood at just the right time and rather than it ending up in the dumpster it landed on my trailer and I drove off into the sunset. LOL
I can see that there is a lot to think about here. I have had the chance to get several machines from there but turned them down because they were 3 phase. I probably would have taken them anyway but didn't have anywhere to store them. I have a problem when trying to research stuff like this because there are so many different variables that go along with it. I guess I just need to find the time to sit down and read some more. I don't see me going CNC any time soon although I would like to but for what I do it would not be cost effective. But being a man that likes big toys it sure would be nice.
Another problem I have is space, when I built my dream shop I built an add on that was 12'X32' just for my machines I had at the time. This one puts a load on that space because of it's size. I have one more work bench that I want to put a nice lathe on but I haven't been able to fine anything in my price range. I have a nice old 10F Atlas lathe that I got a year or so ago that I'm still tooling up, but I want something a little more robust and easier to operate.I hear about people building their own phase converters but with my list of unfinished projects I already have I would probably be too dam old to ever get this bad girl going.
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- Nov 14, 2014
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- 851
Very nice machine! I faced the same dilemma ( VFD V. RPC) when I bought a three phase powered lathe. Eventually I decided to install an RPC from American Rotary. Main reason - the RPC became my primary three phase power supply for other machines.
I retrofitted the shop with conduit, mounted outside the walls, to run circuits to a couple of additional outlets, and all circuits are wired through a sub panel, leading off the converter itself.
Rule of thumb is buy an RPC rated at twice the HP of your motor. This provides the additional power you need at start up. Also, two stage motors - say a 3/2hp motor- apparently you would want to add both stages together E.G., 5 hp, then double that to size an RPC appropriately. As a result, I went with a 10 hp RPC for my 3/2 hp lathe. Very happy I went this direction.
Glenn
I retrofitted the shop with conduit, mounted outside the walls, to run circuits to a couple of additional outlets, and all circuits are wired through a sub panel, leading off the converter itself.
Rule of thumb is buy an RPC rated at twice the HP of your motor. This provides the additional power you need at start up. Also, two stage motors - say a 3/2hp motor- apparently you would want to add both stages together E.G., 5 hp, then double that to size an RPC appropriately. As a result, I went with a 10 hp RPC for my 3/2 hp lathe. Very happy I went this direction.
Glenn
Thanks, yeah she is a real beauty. I've turned down several nice machines because they were 3 phase and sometimes I wish I had went on and either built or bought a RPC. I know of a guy that built his for his shop and maybe I'll go over there and look at what he has set up and decide weather to build one or spring for a store bought one. If I buy one it will probably be something like a 7.5 or maybe a 10 hp if the price is right. I've heard of a place in town where you can buy 3 phase motors for like $7 a hp so $70 dollars for a 10 hp motor isn't that bad. I already have a nice empty panel box that would be large enough to hold all the parts that are needed to put it together. Just a little more research is in order before I decide, I just need to figure out what all is needed to make it work. I have a couple more projects that need to be finished before winter sets in so maybe I can get it working by Thanksgiving or Christmas.
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- May 4, 2015
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Beautiful machine , in super condition , you must be livin right. Good luck with a super machine. I'm very glad you saved it , wish I could save a few my self.