3 phase or no 3 phase?

ddushane

ddushane

Active User
Registered
Joined
Jan 29, 2013
Messages
176
Hey guys I'm need some advise. If you guys could give me some help here I'd appreciate it. I'm trying to get my shop set up, I've got it pretty much done but not quite. My knife shop has plenty of 110 & 220, my engraving room has both as well, I don't have anything hooked up on 220 in the engraving room but pulled a line in there for future unseen needs. I've got another area where I'm going to set up my forging & welding area along with my Logan 1920-1 lathe. My Logan has a 3 phase 3/4 1725 motor on it, I have a 6" x 18" surfacing machine that needs rebuilding but the motor is fine & it's 3 phase, 25lb Little Giant trip hammer that has 3 phase, I'm also wanting a Bridgeport Knee Mill or clone & Lord willing I'll have one one of these days, I have 3 phase to one of the meters on the shop, just needs the electric co. to put in a fuse & then I have to wire it into the shop run ample wire & hook it all up. All of that said here's the question, Since I have access to 3 phase would I be better off to go that way or buy VFDS controllers for each of them & go that way? Thank all of you for your time on this question.

Dwayne
 
Hey Dwayne

You can go the VFD route either way, as they make them for 220 single phase, and multiple voltages in three phase input.

As I type this, I am wondering if three phase input and output VFD is quieter than 220 single phase in? But I digress. They are usually silent, but some make a slight radio-carrier-frequency-noise.

So it really depends on if you want the speed control. I personally LOVE the VFD speed control. Mine even makes a little noise still, probably a setting a little off, and LOVE it. I ave one machine I run off of a rotary PC, and use the original power handles.

You can really fine tune your speeds based of how your cut looks and sounds. I even gradually change speeds As I cut a powered cross feed on a large diameter part to save time roughing. Otherwise you have to cut the same speed at the middle radius as the outside!

Luckily with three phase in, you can take your time and get them when you want. Just don't spend any money own fancy switches, as that would probably pay for half of a VFD!


Bernie
 
Last edited:
If you have access to three phase from the power company, USE IT!!

Since you already have three phases at the meter, it will be easier and cheaper to just run an extra wire and not purchase several hundred dollars worth of VFD. And that way, if you want to add a VFD later, its a piece of cake, and easier to find VFD's that run on three phase. It will also be cheaper in the long run, than using single phase, due to the lower amp draw which will lower your electric bill.

Using a VFD to get three phase is a great alternative when you don't have access to three phase, as with most home machininst, but if you have it, its better to use it.

-Cody
 
Go with the 3-phase! Especially if the power company is right there.
I picked up a huge rotary phase converter.
It opened up all types of options for purchasing great equipment.
It seems that 3 phase machines are less expensive than her 1 phase sisters.
However, I expect that also means that it's more expensive to sell when that time comes.

I don't pretend to understand the science. But, rumor is that 3 phase motors are smoother and more powerful for the same amps. And is therefore less expensive to operate.
I look forward to somebody refuting or supporting this notion.
 
I really appreciate the comments guys, I've got a 200 amp service for my 220 & 110 coming from one pole and 3 ph coming from another pole, I've got a guy that wires pump jacks every day that are 3 ph, he's going to run the new line from the meter to the area I need it. I've heard that with phase converters you lose some of your power but I'm not in any form a electrician. I do some wiring, I've wired all my stuff in my shop, and seven of my machines in my knife shop are variable speed. I have even wired a VFD to a 3ph motor on a belt grinder for a friend of mine, it came with all the directions and it works well but I still can't claim to understand how everything works. It's one thing to follow directions and get good results and it's a whole nother thing to really understand what your doing. I fit the first sometimes. Sometimes I screw up & short things out. :thinking: I will take yalls advise and start with just hooking up all three with 3 phase first and later put the VFD on the Logan, No need for it on the trip hammer or the surfacing machine. & Lord willing, if I get a Bridgeport, I'll put one on it too. Thanks again for yalls help!

Dwayne
 
Heck yeah, if you can 3Ph service, go for it. Almost all VFDs will accept single or 3 Phase and if you decide you need speed control, a VFD is a good solution. I don't know the exact efficiency of a VFD but I'm guessing it's upward of 90 to possibly 95% (depending on model and configuration). They get a little warm but not terribly much, so, they seem to be pretty efficient. One of the hidden benefits to VFDs is that you can "slow-start" a motor and this prevents all the gears in the system from getting pounded on when you flip the switch.

Uglydog... Yes, 3 Phase motors tend to be more efficient for a variety of reasons. They start more efficiently because they don't have/need start caps (but his is a small consideration). Their physical geometry lends itself to smoother and more efficient operation because instead of two distinct pulses pushing the rotor, you get three very nicely synchronized pushes on the rotor in any given cycle -and in between pushes, the rotor does not slow-down as much (thus smoother operation). Also each branch (phase) draws roughly 1/3 the current and it is current (Amperage) that warms-up wires and causes resistive losses. (This is why voltages are transformed up to high values when wires must go long distances). The downside is you need to run 1 additional wire for each circuit.

Ray
 
Thanks Ray for your comments. As soon as I can get some of the electricians time, he'll get it done.

Dwayne
 
One word of caution on the 3 phase service. Billing on 3 phase power is completely different that your residential power. Around here ComEd hits you with a ~$200 per month "commercial" service charge, if you need 3 phase you must be a business so we are going to bend you over charge, that does include some kWh's like more than you will every use. Your electric company might and likely does have different rules. A friend in Wisconsin lives on a farm and get a farm plan for his 3 Phase, his monthly service charge is like 20 or 25 dollars, tolerable, this is on top of he residential service charges and use charges So be for you call the Elec. Co. and say hook me up, check out all the details. Outside of the billing/cost issues from the electric company, 3 phase circuit breaker will run you about $100 a piece. The upside is you can purchase more 3 phase equipment which often sells cheaper than single phase equivalents. You end up paying one way or another. VFDs are good alternatives and beside generating 3 phase power they give you some control over speed. If VFD's were reasonably priced back when I was looking I would have done that route but back then it was a lot cheaper for a RPC which I have. 3 phase was not an option for me at the time.
 
Shade said:
One word of caution on the 3 phase service. Billing on 3 phase power is completely different that your residential power. Around here ComEd hits you with a ~$200 per month "commercial" service charge, if you need 3 phase you must be a business so we are going to bend you over charge, that does include some kWh's like more than you will every use. Your electric company might and likely does have different rules. A friend in Wisconsin lives on a farm and get a farm plan for his 3 Phase, his monthly service charge is like 20 or 25 dollars, tolerable, this is on top of he residential service charges and use charges So be for you call the Elec. Co. and say hook me up, check out all the details. Outside of the billing/cost issues from the electric company, 3 phase circuit breaker will run you about $100 a piece. The upside is you can purchase more 3 phase equipment which often sells cheaper than single phase equivalents. You end up paying one way or another. VFDs are good alternatives and beside generating 3 phase power they give you some control over speed. If VFD's were reasonably priced back when I was looking I would have done that route but back then it was a lot cheaper for a RPC which I have. 3 phase was not an option for me at the time.
Click to expand...

Shade,
I have no experience with 3phase direct as I use a Rotary. Thank you pointing this out, as it was off my radar.
Just like all of my machines, my rotary and 3 phase commercial panel were used.
My cost on the panel with all of the breakers was $130. Everything works well. But, like anything used it comes with risks, fortunately I had the benefit of an apprentice electrician friend.

Choose carefully.
 
Here in West Texas, or at least with my electric company, they are not charging me extra charge for a commercial rate. They are showing it as commercial & my rates are actually lower than our home service, We’re paying 9.7 cents per kilowatt hr on the house & for my shop I just renewed my contract for another 3 yrs & got 7.58 cents per kilowatt hr, that was for regular 200 amp service, but when I asked them about the 3 ph, they said it was all the same price. Not sure if that’s high or low compared to yalls. Thanks for all the different thoughts on this. I appreciate yalls time.

Dwayne
 
You must log in or register to reply here.
Back
Top