Roatary Phase converter ??

[ultrarunner]

Maybe I just got lucky powering my 1 hp tape mill with a 1 hp slave motor?

Really have not had a single issue and it has been decades... don't even need a rope to start the 1 hp slave... I can twist the shaft with my fingers and it starts just fine if I am quick.

 

[Big Barn]

Maybe I just got lucky powering my 1 hp tape mill with a 1 hp slave motor? Really have not had a single issue and it has been decades... don't even need a rope to start the 1 hp slave... I can twist the shaft with my fingers and it starts just fine if I am quick.

I had to google 'tape mill'. Very interesting and too cool!!

Terry

 

[ultrarunner]

It's an old Bridgeport tape mill with Slo-Syn controls... point to point with a third function rotary table... nothing like the continuous path machines today... NC vs CNC

 

[muddstopper]

Been away for a fw days and lots of good info posted. I have sort of talked myself out of getting the old mill. A mill without tooling is sort of like a car without gas, Looks good sitting there, but it aint going to get far. My experience with machine equipment is that the equipment is cheap, its the tooling that cost you. With all the irons I have in the fire right now, if I bought the mill, it would just sit around until I had a real need for it and then I would spend a bunch just getting it ready to work. I dont think the mill is going anywhere soon as he isnt advertiseing it for sale, so maybe it will still be there when I am ready for it. I'll probably go visit the owner this wkend and check it out a little better, see if he'll let me make a few chips or something. He's got the original manual for the machine, I might just spend some time reading thru it.

As for the converter, I think I am going to go ahead and try and build one. I wont be under any pressure to get it built and I can just keep a eye open for the right parts. I'll probably go ahead and pick up the 25hp 3phase motor I was offered, even tho it is way bigger than anything I might possibly need. I can mess with it and as long as I can fiddle around without spending any money, I should be able to learn a little about how to build a rotary converter and either sell or trade it for what ever size i do end up needing.

 

[Shield Arc]

I assembled a phase converter about 30-years ago. I ran a 1-ton chain hoist, and a 18-inch chop saw I built. Mine has such a high pitch scream, it will drive you crazy in no time at all. :confused2:

 

[woodlandfarms]

Silly question... in the end not that important but I assume that to run a motor phase converter the motor will draw electricity as well as the device that needs the 3 phase. What I am getting at is that to provide 3 phase in a non native environment your electric bill is going to go up. Not that this really matters, I doubt many of us use these machines on full day in day out basis but intrigued.

 

[Big Barn]

Silly question... in the end not that important but I assume that to run a motor phase converter the motor will draw electricity as well as the device that needs the 3 phase. What I am getting at is that to provide 3 phase in a non native environment your electric bill is going to go up. Not that this really matters, I doubt many of us use these machines on full day in day out basis but intrigued.

Interesting story. Please do not question me on the technical aspects of it as I am totally ignorant but...

Years ago an elderly retired machinist/inventor/genius friend had a converter in his basement workshop to run his 3 phase welder. He said when welding the meter would actually run backwards. His comment at the time was the more he welded the more money he saved.

Sadly he passed away many years ago. I wish I had the time back then to pay more attention. Terry

 

[newbury]

<snip>
As for the converter, I think I am going to go ahead and try and build one. I wont be under any pressure to get it built and I can just keep a eye open for the right parts. I'll probably go ahead and pick up the 25hp 3phase motor I was offered, even tho it is way bigger than anything I might possibly need. I can mess with it and as long as I can fiddle around without spending any money, I should be able to learn a little about how to build a rotary converter and either sell or trade it for what ever size i do end up needing.

Be careful going too big.
HP requires amps. Check to make sure that whatever you are going to hook it up to will have the amps. No sense buying 25 HP at $15/HP if the max you can use is 10 HP.

Plus they are HEAVY. 25hp may be about 350 lbs. My 10 HP is about 150 lbs I think.

 

[CNC Dan]

Silly question... in the end not that important but I assume that to run a motor phase converter the motor will draw electricity as well as the device that needs the 3 phase. What I am getting at is that to provide 3 phase in a non native environment your electric bill is going to go up. Not that this really matters, I doubt many of us use these machines on full day in day out basis but intrigued.

The converter motor is not loaded, so it won't use much power.

But it may need large wireing, to handle the large currents it may need. The current will be out of phase with the Voltage, so Power draw will be low, but the current may be high.

 

[newbury]

The converter motor is not loaded, so it won't use much power.

But it may need large wireing, to handle the large currents it may need. The current will be out of phase with the Voltage, so Power draw will be low, but the current may be high.

What I was trying to explain was that getting a 25hp converter would probably enable him to power 18 hp of equipment, which when operating will take a lot of amps. If he tries to run 18 hp of loaded equipment off a 40 amp breaker I think it would be a no go.

 

[muddstopper]

I dont see me ever needing 18hp for anything. The most I would run at the same time might be my lathe, which is already single phase, but I am looking for a newer one, and then possibly a mill. Chances are neither machine would run at the same time and a 10hp converter would be more than adequate. The 25hp 3phase motor is a freebie, so guiney pig it will be. I will experiment with it on a 50amp breaker. But I guess I need some clarification on power draw because i am under the impression that no matter how big the motor, it will only use what power it needs to run the 3phase equipment. To small of a converter and you can burn something up, to big a converter??? Can you really get to big? I know it will take some power to make the converter run, but I would think that unless under a good size load, power consumption would be minimal and not much more than what the equipment would draw if it was just hooked to standard 3phase power. I havent had my wrong quota for today so somebody correct me.

 

[CNC Dan]

What I was trying to explain was that getting a 25hp converter would probably enable him to power 18 hp of equipment, which when operating will take a lot of amps. If he tries to run 18 hp of loaded equipment off a 40 amp breaker I think it would be a no go.

Thats right. The breaker will trip due to current level, not power level.

 

[newbury]

I dont see me ever needing 18hp for anything. The most I would run at the same time might be my lathe, which is already single phase, but I am looking for a newer one, and then possibly a mill. Chances are neither machine would run at the same time and a 10hp converter would be more than adequate. The 25hp 3phase motor is a freebie, so guiney pig it will be. I will experiment with it on a 50amp breaker. But I guess I need some clarification on power draw because i am under the impression that no matter how big the motor, it will only use what power it needs to run the 3phase equipment. To small of a converter and you can burn something up, to big a converter??? Can you really get to big? I know it will take some power to make the converter run, but I would think that unless under a good size load, power consumption would be minimal and not much more than what the equipment would draw if it was just hooked to standard 3phase power. I havent had my wrong quota for today so somebody correct me.

I'm pretty sure you are correct in that it won't draw a lot more power than your mill.

 

[Big Barn]

I havent had my wrong quota for today so somebody correct me.

Send me your address, Bill. I think quota is transferable. I can top it up for you.

Terry

 

[CNC Dan]

I'm pretty sure you are correct in that it won't draw a lot more power than your mill.

that's right. won't use much power, but might need a lot of current.

How can it need a lot of current if it uses little power? Power Factor.

The current in an unloaded motor is not in phase with voltage. So at some point in the AC cycle you are drawing power fron the grid, and some point you sending power back into the grid. The result is that you use little power overall, but there is a lot of current flowing. So you may need heavy wire, and large breakers.

 

[Kyle_in_Tex]

Send me your address, Bill. I think quota is transferable. I can top it up for you.

Terry

good one.

 

[ultrarunner]

Interesting story. Please do not question me on the technical aspects of it as I am totally ignorant but...

Years ago an elderly retired machinist/inventor/genius friend had a converter in his basement workshop to run his 3 phase welder. He said when welding the meter would actually run backwards. His comment at the time was the more he welded the more money he saved.

Sadly he passed away many years ago. I wish I had the time back then to pay more attention. Terry

Had the same with my retired machinist friend and he showed me... thing is we all have smart meters now and apparently the smart meters don't run backwards?

 

[Big Barn]

Had the same with my retired machinist friend and he showed me... thing is we all have smart meters now and apparently the smart meters don't run backwards?

I was once told that was deliberate to punish the "alternate source" power users so that they could not receive 'credit' when back feeding into the grid.

Terry

 

[ultrarunner]

I was once told that was deliberate to punish the "alternate source" power users so that they could not receive 'credit' when back feeding into the grid.

Terry

Same has been said here... the analog meters were very simple... all they did was measure the flow of current... adding one way and subtracting the other.

 

[BukitCase]

"I was once told that was deliberate to punish the "alternate source" power users"

Yup, apparently the power companies finally learned a business lesson from the insurance companies ...Steve