Sorry for the silly question but, Do you have 3 phase on your street?
If so It might be worth it to have the power company run it to the house...
Putting the cart before the horse…..Three Phase power question???????
- Thread starter Runs With Scissors
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If so It might be worth it to have the power company run it to the house...
ken erickson
Well-known member
Equipment
B7100 hst, 2650 front mount snowblower, L2501 hst qa loader
In my situation with low HP machines, Bridgeport and Harig surface grinder, I had good results with static converters. They were an inexpensive solution , easy to wire and served me well.
Now if I was running large industrial machines running lots of hours and hogging big chips the rotary converters would have been the way to go.
No internet myth. Here are some experts explaining why. Pay close attention to Forrest Addy who is an expert of experts.
VFD Derating and the Math
I have searched the achives and haven't seen this addressed. If for example I have a 5hp 3phase input VFD and am using single phase. The maximum output hp is 5/(sq rt 3)= 2.88hp. I assume that using a 3 hp motor is acceptable, but only would be capable of creating 2.88hp. So could one use a 5hp...
www.practicalmachinist.com
You will find that same info straight from the OEM sites
Basically when using single phase input you are increasing input current draw on L1 and L2 beyond the 3 phase design rating. You have to be very careful when shopping to read the manufacturers fine print. Most headline ratings are for 3P input and the derating number is hidden in the fine print.
Dan
It depends on the converter.
I say they suck because with most low cost units you only get 2/3 the rated motor HP and the motors run hot when loaded. The cheap units are simply motor starters and you are actually running the motor on just two of the three legs. Not at all good for the motor. Better ones also have run caps and you get a third leg and about 80% power. At this point you have an RPC minus the idler motor. Adding an idler motor gets you an RPC, roughly 98% power and better balanced legs.
Higher end solid state converters generate quality three leg power and are a different and much more costly animal.
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I'm sure your right.
So, what is the advantage of a 3ph machine?
Other than they are cheaper because very few folks can power them.... (correctly)
I mean, for a hobbiest guy wouldn't it be more practical to buy a single phase machine OR swap out the motor for a single phase lump?
That has to be possible... No?
There are a multitude of advantages to 3 phase induction motors. Ask Google for a list.
But the biggy is single phase motors top out around 5-7 HP and even at that relatively small size require "massive' input current draws.
Take a look at the big green mill in my earlier post. It has 4 motors, a 7.5HP main spindle, a 3 HP vertical head, a 3HP knee motor, and a 1/8 HP coolant pump. Converting it and all the electrical controls to single phase is not practical but powering it with a El Cheapo DIY rotary phase converter is.
Dan
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Russell King
Well-known member
Lifetime Member
Equipment
L185F, Modern Ag Competitor 4’ shredder, Rhino tiller, rear dirt scoop
Just to clarify…How many converters did you use? If more than one why?
I can swear when I was discussing the use of small single phase input converters to get three phases out I was told by a power electronics engineer that more than one would be required but I may have been understanding this incorrectly or maybe it was to change the voltage also and go to three phases. I was just discussing it casually as in ”is that possible and what people are doing now”.
I worked at an electric motor (large industrial motors - usually 4000V 3 phase) that also designed and built adjustable speed converters to drive the motors. So they would commonly use “more slices” to increase power output where a slice was similar to a slave drive that all communicated to each other through a master control slice that was the “brains” that controlled most everything.
As a mechanical engineer they were interesting devices that just made my job a bit more complicated due to the various speeds the motors could be operated on (two pole motors on 60 Hz power usually went through the first critical shaft speed and ran fine at 3600 RPMs but not well at 70 to 80% synchronous speed for example)
In the class of motors abd inverters we are talking about an inverter produces 3 phase output. Period. You only need one to convert 240v single phase input to 240v 3 phase output.
If your machine has mulltiple motors and you want to use the inverter to CONTROL each one separately you need multiple inverters - one for each motor.
Dan
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I have been running my Bridgeport on a static phase controller for 30 years without a problem but getting ready to switch to a VFD. For my CNC spindles I use Chinese VFDs. I switched to a single phase motor on my southbend lathe.
When I first got my vertical mill, I built a rotary phase converter for it. It was fine and, at the time, the least expensive way to go. I long ago ditched the RPC and switched to VFD (actually two VFDs - one for the feed motor and one for the spindle). Hell - I've put VFDs on my belt sander and bandsaw too...
Hooking up a VFD takes a different skill set than building a rotary phase converter - a skill set that involves reading and understanding the Chinglesh owner's manual that'll come with the VFD. But lots of folks have done it.
Anyway - get the VFD. All the cool kids are doing it...
Hooking up a VFD takes a different skill set than building a rotary phase converter - a skill set that involves reading and understanding the Chinglesh owner's manual that'll come with the VFD. But lots of folks have done it.
Anyway - get the VFD. All the cool kids are doing it...
Lil Foot
Well-known member
Lifetime Member
Equipment
1979 B7100DT Gear, Nissan Hanix N150-2 Excavator
My mill is 2hp 220v 3 phase, powered with a Phase-a-matic PAM-300 solid state 1 phase to 3 phase converter.
It has run flawlessly for over 30 years.
I pulled the power from an unused 30a 220v dryer circuit.
I'm told that this setup will provide less than full power, but I have never been able to detect any evidence of that.
I also run my 220v 3 phase diamond/alox tool grinder on the same circuit, but not at the same time.
I have a 12-4 rubber cord from the converter connected to the mill through a 20A 250V 3 phase twist lock cord cap, and just disconnect it from the mill and connect it to the grinder's cord with the same cord/cap.
I forward/reverse power tap with large taps (1"-8 UNC & 1"-12 UNF) and have taken heavy enough cuts to make the belt slip with no problems from the converter.
I suppose if I had it to do over again, I might go with a VFD, but this was cheap & fast to acquire & hook up.
I think I installed it & was up and running in less than an hour after the converter was delivered.
It has run flawlessly for over 30 years.
I pulled the power from an unused 30a 220v dryer circuit.
I'm told that this setup will provide less than full power, but I have never been able to detect any evidence of that.
I also run my 220v 3 phase diamond/alox tool grinder on the same circuit, but not at the same time.
I have a 12-4 rubber cord from the converter connected to the mill through a 20A 250V 3 phase twist lock cord cap, and just disconnect it from the mill and connect it to the grinder's cord with the same cord/cap.
I forward/reverse power tap with large taps (1"-8 UNC & 1"-12 UNF) and have taken heavy enough cuts to make the belt slip with no problems from the converter.
I suppose if I had it to do over again, I might go with a VFD, but this was cheap & fast to acquire & hook up.
I think I installed it & was up and running in less than an hour after the converter was delivered.
Lil Foot
Well-known member
Lifetime Member
Equipment
1979 B7100DT Gear, Nissan Hanix N150-2 Excavator
When the company closed down the quartz research lab I worked in, I considered buying the 11-20 Blanchard grinder for personal use.
I contacted the local power company about bringing in power for it, and when they got through laughing, they told me it would be cheaper for me to buy a property in an industrial area that already had the power the grinder needed.
If I remember right, it was 480V, 60A, 3 phase.
20hp spindle, 14hp table drive, 8hp spindle feed, 4hp coolant pump.
Sigh, it was a fabulous machine.
I contacted the local power company about bringing in power for it, and when they got through laughing, they told me it would be cheaper for me to buy a property in an industrial area that already had the power the grinder needed.
If I remember right, it was 480V, 60A, 3 phase.
20hp spindle, 14hp table drive, 8hp spindle feed, 4hp coolant pump.
Sigh, it was a fabulous machine.
Runs With Scissors
Well-known member
Equipment
L2501 TLB , Grappel, Brush Hog, Box Blade, Ballast box, Forks, Tiller, PH digger
WOW guys, thanks for all the info.
Looks like I have some “homework” to do.
So this whole “power tapping” thing looks to me like it would "hurt the machine”.
From a beginners perpsctive, doesn’t that "instant reversing" damage the gears of the machine?
I have seen lots of videos of people doing it, but I still have a hard time wrapping my head around how in the world that can be OK to do to a machine. And would I miss not having the capability???????
I’m a “Cherry Boy” when it comea to 3 phase power.
I’m still reading through the plethora of material provided by y’all, and have not ruled out anything yet.
@TheOldHokie do you have any recommendations for building one of these? (i.e. brands to get or stay away from? Are they loud? )
The bottom option is very intriguing. I currently have a 1 HP machine, so “technically” I would be upgrading my HP…..(although it’s a Chi-Com motor so…..)
Attention VFD proponents……..
Since I have no experience with VFD’s, any reccomendations on brands? I obvouisly went to Amazon and started looking.
Lots of “cheap options” but they almost seem “too good , to be true” ……
Thanks for the help/advice/opinions so far though…….
Looks like I have some “homework” to do.
So this whole “power tapping” thing looks to me like it would "hurt the machine”.
From a beginners perpsctive, doesn’t that "instant reversing" damage the gears of the machine?
I have seen lots of videos of people doing it, but I still have a hard time wrapping my head around how in the world that can be OK to do to a machine. And would I miss not having the capability???????
Yes sir, you are probably right about that. Hence my question.
I’m a “Cherry Boy” when it comea to 3 phase power.
I’m still reading through the plethora of material provided by y’all, and have not ruled out anything yet.
@TheOldHokie do you have any recommendations for building one of these? (i.e. brands to get or stay away from? Are they loud? )
Two options
Phase Technologies Home | Variable Frequency Drives and Digital Phase Converters | Phase Technologies
POWER ELECTRONICS, POWERFUL SOLUTIONS At Phase, we understand no two installations are exactly the same and our manufacturing process reflects that. We treat every order like a custom order, meaning every unit that leaves our facility is hand built, fully tested, and approved for installation.www.phasetechnologies.com
I bought a digital phase converter 20 years ago.
Set it up in my shop wired the output to a 3 phase panel.
Wired my whole 3 phase shop to the panel .
I have moved twice since then and it all came with me.
I have had zero problem with this setup.
It comes with a price though. 20HP converter in 2005 was $6000.00
I was running 2 CNC machining centers, compressor, grinder, lathe etc.
If this is going to be your only need for 3 phase....
eliminate the need.
Single Phase Conversion Kit for 1 HP Bridgeport Motor | SP2SP-WW
Bore and Borach of Pully Not Required. See the product descriptions below to ensure you're selecting the right product.machinerypartsdepot.com
The bottom option is very intriguing. I currently have a 1 HP machine, so “technically” I would be upgrading my HP…..(although it’s a Chi-Com motor so…..
)Attention VFD proponents……..
Since I have no experience with VFD’s, any reccomendations on brands? I obvouisly went to Amazon and started looking.
Lots of “cheap options” but they almost seem “too good , to be true” ……
Thanks for the help/advice/opinions so far though…….
Runs With Scissors
Well-known member
Equipment
L2501 TLB , Grappel, Brush Hog, Box Blade, Ballast box, Forks, Tiller, PH digger
So you are using "Method 1” in their description?My mill is 2hp 220v 3 phase, powered with a Phase-a-matic PAM-300 solid state 1 phase to 3 phase converter.
It has run flawlessly for over 30 years.
I pulled the power from an unused 30a 220v dryer circuit.
I'm told that this setup will provide less than full power, but I have never been able to detect any evidence of that.
I also run my 220v 3 phase diamond/alox tool grinder on the same circuit, but not at the same time.
I have a 12-4 rubber cord from the converter connected to the mill through a 20A 250V 3 phase twist lock cord cap, and just disconnect it from the mill and connect it to the grinder's cord with the same cord/cap.
I forward/reverse power tap with large taps (1"-8 UNC & 1"-12 UNF) and have taken heavy enough cuts to make the belt slip with no problems from the converter.
I suppose if I had it to do over again, I might go with a VFD, but this was cheap & fast to acquire & hook up.
I think I installed it & was up and running in less than an hour after the converter was delivered.
METHOD #1
Using the Phase-A-Matic™ Static Converter only will produce approximately 2/3 normal HP.* This method is inexpensive, the most popular, provides excellent results on most machines tools and numerous other uses. Motor speed is not changed. Most two-speed motors, power feeds, coolant pumps, etc., will operate normally. Motor will instant reverse. There is nothing to change. All switch gear will work normally. *Refers to wye-wound motors; delta-wound motors will run at 50% rated HP. Delta-wound motors are very rare in the USA, occasionally being found on some imported equipment, and are particularly found on German and Italian machines.
Runs With Scissors
Well-known member
Equipment
L2501 TLB , Grappel, Brush Hog, Box Blade, Ballast box, Forks, Tiller, PH digger
Runs With Scissors
Well-known member
Equipment
L2501 TLB , Grappel, Brush Hog, Box Blade, Ballast box, Forks, Tiller, PH digger
You can.build a 2 HP rotary phase converter yourself using a used 2HP 3 phase idler motor and a handfull of capacitors. Its cheap, provides clean 3p power and full load motor HP. Just plug the Bridgeport in and it will operate exactly as it was designed. Did you get one with a variable speed head? If not thats the only advantage to using a VFD.WOW guys, thanks for all the info.
Looks like I have some “homework” to do.
So this whole “power tapping” thing looks to me like it would "hurt the machine”.
From a beginners perpsctive, doesn’t that "instant reversing" damage the gears of the machine?
I have seen lots of videos of people doing it, but I still have a hard time wrapping my head around how in the world that can be OK to do to a machine. And would I miss not having the capability???????
Yes sir, you are probably right about that. Hence my question.
I’m a “Cherry Boy” when it comea to 3 phase power.
I’m still reading through the plethora of material provided by y’all, and have not ruled out anything yet.
@TheOldHokie do you have any recommendations for building one of these? (i.e. brands to get or stay away from? Are they loud? )
The bottom option is very intriguing. I currently have a 1 HP machine, so “technically” I would be upgrading my HP…..(although it’s a Chi-Com motor so…..
Attention VFD proponents……..
Since I have no experience with VFD’s, any reccomendations on brands? I obvouisly went to Amazon and started looking.
Lots of “cheap options” but they almost seem “too good , to be true” ……
Thanks for the help/advice/opinions so far though…….
Three phase motors are self reversing. My Cincinnati has a push button on the end of the quill feed lever for reversing the spindle when doing rigid tapping operations. There are also adjustable travel stops on the quill that allow you to set the depth for repeated operations and the machine automagically does it for you. Its a bit noisy but at tapping spindle speeds there is no risk of damage to the machine.
I will be happy to walk you through a build. Its not complicated and you will come away with a nuch clearer understsndung of how 3P power works. At least investigate what you do and dont get with the various options. If using a static converter be very carrful about what you buy. The cheap ones are just a start cap in a box snd you are actually running the notor with single phase power. Thats a FAULT condition that a VFD would sense and shutdown the motor.
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