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So many posts about phase conversion to 3-phase

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DFWKen

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#31
The new lathe arrived today. UPS called and said it would be delivered yesterday, but they were wrong. It missed the truck in Kansas City. Nonetheless, it's here today.
so is a 10hp rotary phase converter. It was listed on Craigslist about 70 miles from my home. I offered a low-ball offer and he came back with a slightly low-ball price. I committed and traveled to Burleson, Texas to pick it up. Tested it on 220 VAC and it started and ran quietly.

I had also made a low-ball offer on eBay for another rotary phase converter; not expecting to win it. This one included a manufactured control box and a 10hp motor with a shaft sticking out. To my surprise, the seller agreed to my low ball offer. So I paid for it. Now, I have two nice 10hp rotary phase converters. Not sure which I want to use for my workshop. Will sell the other.

When UPS delivered, the worker said that they're not allowed to drive in allys. Bummer. I'd even gone to the local UPS freight office a couple of days ago to make sure that they could deliver via bobtail and liftgate in my rear entry. They said yes. Today, they said, "No".
Without a plan B, I didn't know what to do! Too far to walk it around back on a pallet jack. But the UPS guy was very friendly and cooperative. He understood my plight. so he drove to the end of the alley where we off loaded. Then, I used a towing strap and my pickup to pull it about 300 yards up the alley to my driveway. I tipped him very nicely! He deserved it.

Took all the rest of the day and into the night to get it uncased and moved into my workshop. I have a 4,000 lb shop hoist. It did the job nicely, although lifting it off the foot-tall pallet was a chore requiring lifting the pallet 8" in several steps with cribbage so that the legs of the shop crane would go under. With my towing strap, I was able to raise the lathe off the pallet, slide the heavy pallet out, and lowered the lathe to the pavement (after removing the center panel and brake so that the legs would fit without bending the brake). Pulled it into my workshop with a come-along and put it in its new home. It'll be there now for the duration. It's going to take days and plenty of solvent to get the preservative off. Then, I'll hook up the phase converter (still not sure which converter to keep and which to resell), and go through the several pages of initial lathe setup. I think I'll take a break and level it tonight.

I think I should start a new post about setting up my new 14 x 40 lathe in case anyone is interested.





 

Downunder Bob

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#32
The new lathe arrived today. UPS called and said it would be delivered yesterday, but they were wrong. It missed the truck in Kansas City. Nonetheless, it's here today.
so is a 10hp rotary phase converter. It was listed on Craigslist about 70 miles from my home. I offered a low-ball offer and he came back with a slightly low-ball price. I committed and traveled to Burleson, Texas to pick it up. Tested it on 220 VAC and it started and ran quietly.

I had also made a low-ball offer on eBay for another rotary phase converter; not expecting to win it. This one included a manufactured control box and a 10hp motor with a shaft sticking out. To my surprise, the seller agreed to my low ball offer. So I paid for it. Now, I have two nice 10hp rotary phase converters. Not sure which I want to use for my workshop. Will sell the other.

When UPS delivered, the worker said that they're not allowed to drive in allys. Bummer. I'd even gone to the local UPS freight office a couple of days ago to make sure that they could deliver via bobtail and liftgate in my rear entry. They said yes. Today, they said, "No".
Without a plan B, I didn't know what to do! Too far to walk it around back on a pallet jack. But the UPS guy was very friendly and cooperative. He understood my plight. so he drove to the end of the alley where we off loaded. Then, I used a towing strap and my pickup to pull it about 300 yards up the alley to my driveway. I tipped him very nicely! He deserved it.

Took all the rest of the day and into the night to get it uncased and moved into my workshop. I have a 4,000 lb shop hoist. It did the job nicely, although lifting it off the foot-tall pallet was a chore requiring lifting the pallet 8" in several steps with cribbage so that the legs of the shop crane would go under. With my towing strap, I was able to raise the lathe off the pallet, slide the heavy pallet out, and lowered the lathe to the pavement (after removing the center panel and brake so that the legs would fit without bending the brake). Pulled it into my workshop with a come-along and put it in its new home. It'll be there now for the duration. It's going to take days and plenty of solvent to get the preservative off. Then, I'll hook up the phase converter (still not sure which converter to keep and which to resell), and go through the several pages of initial lathe setup. I think I'll take a break and level it tonight.

I think I should start a new post about setting up my new 14 x 40 lathe in case anyone is interested.





 

Downunder Bob

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#33
Nice looking machine, will be waiting for install and setup pics and story.
 

DFWKen

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#34
Phase converter all wired up with appropriate fused (breaker) power main and supplying 3-phase power to my lathe. All seems well.
HOWEVER, the idling current draw of the converter seems excessive. With no 3-phase load, the converter/motor is drawing 15 amps on one leg and 14 on the other from the single phase power main. I was expecting much lower power consumption when not under any load other than its own internal friction and power losses. (like almost zero . . .just enough to keep the Phase Converter spinning.

Does 14 amps and 14 amps sound correct?
 

Ulma Doctor

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#35
14A @ 10hp is quite good for an idling 3 phase motor on single phase supply
is your line voltage closer to 220v or is it closer to 240v?
 

Downunder Bob

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#36
Phase converter all wired up with appropriate fused (breaker) power main and supplying 3-phase power to my lathe. All seems well.
HOWEVER, the idling current draw of the converter seems excessive. With no 3-phase load, the converter/motor is drawing 15 amps on one leg and 14 on the other from the single phase power main. I was expecting much lower power consumption when not under any load other than its own internal friction and power losses. (like almost zero . . .just enough to keep the Phase Converter spinning.

Does 14 amps and 14 amps sound correct?
It does seam rather high, I assume we're talking about a rotary converter here. does it spin freely with the power off, , (bearings), what size is the motor? could you be measuring circulating currents by measuring the phases? what is the current draw back at the single phase supply?
 

DFWKen

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#37
It does seam rather high, I assume we're talking about a rotary converter here. does it spin freely with the power off, , (bearings), what size is the motor? could you be measuring circulating currents by measuring the phases? what is the current draw back at the single phase supply?
I'll need to go measure the unloaded 220VAC primary to see if it's closer to 240V or not.

Bobshobby, the current draw is measured at the single phase supply to the 3-phase motor while it is running and there is absolutely no 3-phase load at all. It seemed high to me and would add a hunk of $$$ to our electric bill if the phase converter was accidentally left ON overnight.

I was going to mount the converter outside in a weather-resistant enclosure to get the noise out of the workshop. But that invites accidentally leaving it energized. I should put a motor timer on the motor start that turns it off in 3 hours unless I extend the time.
 

Ulma Doctor

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#38
15a is roughly about 2hp equivalent consumption of the single phase line @230v
 

whitmore

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#39
Phase converter all wired up with appropriate fused (breaker) power main and supplying 3-phase power to my lathe. All seems well.
HOWEVER, the idling current draw of the converter seems excessive. With no 3-phase load, the converter/motor is drawing 15 amps on one leg and 14 on the other from the single phase power main.
That might not be energy that you're paying the power company for; there's a phase-angle correction,
which you can check. Turn off electric water heater and furnace/AC, look at five minutes of
power-company-meter reading with the RPC running, then turn it off and look at another five minutes.

Some of the current you're measuring is due to the start/run capacitors in the RPC, and doesn't
mean real electric power. The power meter indicates this, but ammeter measurements don't.
 

Downunder Bob

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#40
I'll need to go measure the unloaded 220VAC primary to see if it's closer to 240V or not.

Bobshobby, the current draw is measured at the single phase supply to the 3-phase motor while it is running and there is absolutely no 3-phase load at all. It seemed high to me and would add a hunk of $$$ to our electric bill if the phase converter was accidentally left ON overnight.

I was going to mount the converter outside in a weather-resistant enclosure to get the noise out of the workshop. But that invites accidentally leaving it energized. I should put a motor timer on the motor start that turns it off in 3 hours unless I extend the time.
OK you had me a little confused, you said 15A on one leg and 14A on another, I assumed you were referring to phase leads, so am I to assume you are referring to the single phase active and neutral leads,if so they should read the same. I still think it's rather high although Ulma doctor says it's about right. And I suspect he knows more about it than I do. It will be interesting to see how much it draws when running a good 3 phase load.

As for running the RPC outside or in any out of the way place, you could wire up a lamp that will show when the RPC is powered on. A mate of mine did that with his shop compressor, he had a green light next to the remote on off switch.
 

Downunder Bob

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#41
15a is roughly about 2hp equivalent consumption of the single phase line @230v
Mike are you sure that it's about 2HP. I would have thought it would be closer to 4HP. unless it has a very poor power factor.
 

Ulma Doctor

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#42
Mike are you sure that it's about 2HP. I would have thought it would be closer to 4HP. unless it has a very poor power factor.
the draw is slightly greater than 2hp on the single phase input, a 3hp single phase motor would draw around 17a full load current
full load current for a 3 phase 10 hp motor running on 3 phase 230v, is about 28 amps
 

Downunder Bob

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#43
the draw is slightly greater than 2hp on the single phase input, a 3hp single phase motor would draw around 17a full load current
full load current for a 3 phase 10 hp motor running on 3 phase 230v, is about 28 amps
Mike, I have just realised my confusion, I'm not used to thinking in terms of 3 ph at those low voltages, here in downunder all our single ph is 240v and our 3 ph is 415 v.As a result I'm thinking of currents roughly half of what you are using. Sorry, thanks for the patience.
 

Ulma Doctor

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#44
No worries mate!
We have 240v single phase and 208 or 230v 3 phase as well as 440/460v 3 phase
I have wired up a few machines that came from down under to run on our supply
The machines come in with 415v 5 wire plugs
I omit the blue neutral and i convert the control systems. the remaining 4 wires do the work with 208-230v 3 phase supply to the machine.
The conversions are battle tested and have served many well

All the best
 

DFWKen

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#45
That might not be energy that you're paying the power company for; there's a phase-angle correction,
which you can check. Turn off electric water heater and furnace/AC, look at five minutes of
power-company-meter reading with the RPC running, then turn it off and look at another five minutes.

Some of the current you're measuring is due to the start/run capacitors in the RPC, and doesn't
mean real electric power. The power meter indicates this, but ammeter measurements don't.
Interesting, Whitmore. I'll do that. I just figured that if my ammeter shows 15 amps, then that's what I'm paying the power company for.


OK you had me a little confused, you said 15A on one leg and 14A on another, I assumed you were referring to phase leads, so am I to assume you are referring to the single phase active and neutral leads,if so they should read the same. I still think it's rather high although Ulma doctor says it's about right. And I suspect he knows more about it than I do. It will be interesting to see how much it draws when running a good 3 phase load.

As for running the RPC outside or in any out of the way place, you could wire up a lamp that will show when the RPC is powered on. A mate of mine did that with his shop compressor, he had a green light next to the remote on off switch.
Thank you, Bobshobby. I'm using a clamp-type ammeter, clamping it around one input lead to the phase converter motor and then the other. It does seem strange that they're not reading the same current. All current going into the motor should also be going out, shouldn't it? But indeed, one leg consistently reads 14 amps while the other reads 15.
 

Downunder Bob

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#46
Interesting, Whitmore. I'll do that. I just figured that if my ammeter shows 15 amps, then that's what I'm paying the power company for.




Thank you, Bobshobby. I'm using a clamp-type ammeter, clamping it around one input lead to the phase converter motor and then the other. It does seem strange that they're not reading the same current. All current going into the motor should also be going out, shouldn't it? But indeed, one leg consistently reads 14 amps while the other reads 15.
Interesting and somewhat intriguing, I can only assume you are losing 1 Amp somewhere. Is it possible you have an earth leakage problem? Do you have earth leakage breakers on your system or not? I wonder if Ulma doctor can throw any light on this, as it is my understanding that current in equals current out.
 

Downunder Bob

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#47
No worries mate!
We have 240v single phase and 208 or 230v 3 phase as well as 440/460v 3 phase
I have wired up a few machines that came from down under to run on our supply
The machines come in with 415v 5 wire plugs
I omit the blue neutral and i convert the control systems. the remaining 4 wires do the work with 208-230v 3 phase supply to the machine.
The conversions are battle tested and have served many well

All the best
Glad you know what you are doing, electricity was not my best subject when I studied marine engineering, sure I get the basics of generation and distribution, even fault finding and repair on a known system, but when it comes to wiring up motors onto a system that is different from their name plate, I'm well out of my depth. BTW your 5 wire 3ph plug woud have been L1, L2, L3, N and E. If you leave the blue out that is the N does that mean you are usinhg the E (yellow/ green or just green on older stuff ) as your N. Are you wiring star (WYE) or Delta?

The 240v single ph here is about to change to 230v to bring us into line with Europe as they change from 220 also to 230v. We will retain the 50hz and they will keep their 60hz, So it's only a partial common system, but we will avoid the problem we have had for years where asian manufacturers design and build to the much larger European market at the old 220v and just relabel them 240v for us here in downunder, as a result we have had an unacceptably high level of failures in motors, transformers, and other induction devices Taiwan has recently and finally caught on, but the rest of asia, China in particular is still a problem.
 

British Steel

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#48
Hi Bob,

Most 3-phase machinery doesn't use the neutral from what I've seen, when it does it's to get 240 for a control and low-volt lighting transformer or such - most of those can go across 2 phases using their 415v tappings instead, so no problem losing the Neutral.

NEVER use the green/yellow Earthing (Ground, USAn) wire for carrying load current, it's there to keep you safe! If used for load and a Disaster happens, e.g. a short to the machine frame, it's intended to keep the conductive parts (and anybody touching them) at local earth voltage (e.g. no volts at all!) so no current flows through you, the user, then the current should either blow a fuse/breaker or (the safer way) trip the RCD/GFI - if load current is passing through, the earth resistance can be enough to raise the machine to a dangerous voltage although it *SHOULD* trip the RCD/GFI - I've experienced this on green Chinese machines sold here in England with faulty electrics and high-resistance cables direct from the factory... Other importers may be as bad or worse.

The UK changed from 240 to 230 as well, "harmonising" with Europe, but there's a 5% supply tolerance on that 230v, a lot of folk in the UK complained that they weren't going to get the same power per amp and so it would put up prices, then it was explained that the voltage was staying at 240 as 230 + 5% = 241v, similar in the EU, 230 - 5% = 219v... SO everybody's happy, and the Eurocrats get to enjoy long sessions in council with 5-star meals and hotels on their expense accounts, making up more regulations that make no difference to anybody's lives :)

One bit of info' re line frequencies, Europe's on 50 Hz, has been since the 40s/50s, as far as I know it's only the US and the "Pacific Rim" countries that are on 60Hz - and using 60Hz kit on 50Hz is more of a problem than the 5% voltage difference, as transformers and induction motors are "Volts per Hertz" devices and need lower applied voltages for the same current at lower frequencies (somewhere between 15 and 20% lower) - which is why USAn kit sometimes blows on everywhere else's mains, probably why the Asian devices blew, designed for 60Hz? As an example, exporting UK 415v 3-phase kit to the USA works, as their 460 - 480v at 60Hz gives near as dammit the same current, coming back the other way ditto, as their 460-480v kit's being fed 380 - 415 so stays within current ratings - not so good going from 220/60 to 240/50 though, where it should be running closer to 200v... Lets the Magic Smoke out for good :(

Dave H. (the other one)

P.S. - Glossary!

RCD - Residual Current Device (sometimes "Disconnect") - has phase and neutral conductors passing through it inside a transformer, any imbalance between phase and neutral currents means current is going somewhere else, i.e. to earth so there's a fault - it trips and disconnects the phase and neutral to keep the appliance / installation safe, usually at 30 milliamps as that's been ruled the max safe current a human can take in about 99% of electrocutions.

GFI - Ground Fault Interrupter - much the same but translated into USAn!
 
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Ulma Doctor

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#49
Glad you know what you are doing, electricity was not my best subject when I studied marine engineering, sure I get the basics of generation and distribution, even fault finding and repair on a known system, but when it comes to wiring up motors onto a system that is different from their name plate, I'm well out of my depth. BTW your 5 wire 3ph plug woud have been L1, L2, L3, N and E. If you leave the blue out that is the N does that mean you are usinhg the E (yellow/ green or just green on older stuff ) as your N. Are you wiring star (WYE) or Delta?
Hi Bob,
Yes sir, the green/yellow is earth ground- there is no neutral being used, just 3 hots and a ground lead
90% of the stuff i work on is wired WYE, i have only a few pieces of equipment that use Delta wired motors
 
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