I'm looking to purchase a cabinet saw. I have 220 in my shop currently and plan on buying 220 machines when ever possible. While doing my research, I've heard people mention single phase and three phase power but without the benefits or limitations of each. Can anyone help me understand this a little bit more or point me in a direction? -mike
I can think of two benefits of 3-phase - More HP in a smaller frame motor. Reduced electrical cost both in demand and KW.
Keep in mind that having 220 in your shop doesn't mean you have 3-phase available.
Erik
Three phase power is more efficient. Typically 3 phase power is only available in commercial and industrial locations. One doesn't usually find it in a residence. Three phase motors require a magnetic motor starter with short circuit and overload protection.
Ms Leslie
you aren't likely to have 3 phase power unless you are in an industrial zoned area. your home would be single phase.
dave
Mike B wrote:
Is there anyway to determine what I have short of having an electrician come out? Thanks for the responses. -mike
You should be able to look at the consumption meter and see what it says also, you can call your utility co and ask them. If you have 3-Ph they will know.
Erik
Mike, discussions of 3-phase may well be moot if you're in the US. It's what industrial users of 5+ HP motors use, and not normally available to residential customers. This is probably a good thing to examine
BTW, capacitor starters generate pulses to get a single-phase motor running, then cut out. Capacitor run motors use an interboost from the run capacitor to get greater output from a smaller motor.
Yes, real easy. 220 (actually 240v) is single phase. It would be real strange for a residence to have three phase. So, you have single phase.
Your question should be whether to use 240v or 120v.
If you have 240v in your shop, then you should use it. It simply works better; do a search and see what people say about it. If you don't have 240v, then 120v should be okay also.
Lots of larger offices and most all factories are fed with 3 phase because it's cost effective and more efficient. Smaller buildings and residential are fed with single phase.
220 is single phase. Your wise in utilizing it. Upgrading to 3-phase power would require a whole new "service entrance", main panel, and perhaps "line work" to replace the line transformer feeding your location. Heck, you might not even have it available at the pole in your location. If you're situation is substantial, and your so inclined, call up a local electrical contractor that advertises "commercial and industrial" and talk to their service department manager. I'm sure he'd be glad to talk with you and clarify the finer points. If you two figure out it's worth a look-over he'll come by or send someone over to eyeball the location to see if it's feasible and makeup a quote. It's that easy.Hope this helps, Jon Veeneman
Dave, the key word there is "business". It's *very* rare in the US to have
3-phase power in a residence.-- Regards, Doug Miller (alphageek-at-milmac-dot-com)
Best explanation I've seen is on the Old Woodworking Machines site
(Even if the bunch of tightasses don't think _my_ saw is good enough!)
If you've got it, or can get it cheaply, three phase every time.
-- Die Gotterspammerung - Junkmail of the Gods
guess I didn't make myself clear, Doug. I live in San Jose, but had a business in Santa Clara. The VOLTAGE is 208 in Santa Clara, as opposed to 220 (or thereabouts) in San Jose. NOW do you understand what I was getting at? I thought you'd understand my business was in an industrial area since I had 3 phase power!!!
dave
Doug Miller wrote:
I'm pretty sure the power poles running along the front of my lot are three phase. I really doubt the power company would install a transformer and the underground feed to my shop that would provide me with three phase power, even if it is there. If they did do it, they would probably charge an arm and a leg.
I actually called one time to inquire about three phase and just got shuffled from department to department and gave up at the time.
The power for my house actually comes from poles run down the center of my two lots. There was an alley easement, but it was vacated many years ago. The power company has to drive on customer driveways and across customer yards to access their poles and wires.
Brian Elfert
Look at the main breaker in your distribution panel. If it has two handles tied together then you gave 220v single phase. If there are three , then you have 3 phase. If it is a residential installation, I doubt you have 3-phase power.
-- Al Reid
"It ain't what you don't know that gets you into trouble. It's what you know for sure that just ain't so." --- Mark Twain
All of Santa Clara, or just industrial areas?
208v/120v is comm> guess I didn't make myself clear, Doug. I live in San Jose, but had aI looked into 3 phase too, back when I was working for a company that regularly tossed 3p motors in the trash. I did have 3 phase primaries on the street. What I *might* have been able to get was 3p center tapped delta, 240 between phases, (2) 120v phases and a wild leg (208 to ground). It only required one extra transformer. It was still going to be expensive. I would need to install a 3p service disconnect, rewire my current panel as a sub and install another
3p sub. By the time I paid for the upgrade from the utility and upgraded my service I figured I could buy a lifetime supply of single phase motors so I passed. Where I live now I only have a single phase primary on the street so 3p is pretty much out of the question. There are tricks with capacitors that allow you to run 3p motors on single phase but the lack of efficiency in this trick negates any saving a 3p motor could get you. It might be a solution if you are getting the 3p equipment virtually for free and you don't use it a lot.
Would this type of service even work for three phase equipment?
The reason I want to do this is for big equipment like wide belt sanders and big planers. Ever try finding a used wide belt sander in single phase? I've got a better chance at the lottery. Three phase sanders are a dime a dozen. You can get new wide belt sanders in 10HP single phase, but only 25" and the cost is about $8,000.
The 20" Jet/Powermatic taiwanese planer for $2000 that is single phase is just junk compared to a used Powermatic. For $2,000 I could easily find an 18" or 20" old Powermatic with a three phase motor.
Very rarely you will see a Powermatic planer with single phase motor but the owners price them sky high because they know how rare the single phase beasts are.
Brian Elfert
Good stuff. Thanks for the input everyone! -mike
an arm and a leg.
Actually if the situation warrents it (demand is there) I don't believe they charge to provide power (up to the "service wiring"). Naturally they aren't going to do all that for a heating pad in fido's dog house!
If you called your local power co. I can believe that. You'd have gotten some real answers from a contractor. You know.. in regards to quoting a possible job.
Jon Veeneman
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