33 amp, 3-phase Clothes Dryer

Discussion in 'Electrical Forum discussion & Blog' started by molo, Feb 2, 2009.

  1. molo

    molo Member

    Messages:
    864
    Location:
    cold new york
    Hi,

    I'm considering buying a Commercial SpeedQueen Electric Dryer.

    The electrical requirements are 33 amps and 3-phase. 240 3-phase.
    Can a standard residential electric supply provide this?

    Thanks for any replies,
    Molo
  2. Igor

    Igor New Member

    Messages:
    19
    Location:
    Oregon
    No. Three-phase power is usually available only in commercial and industrial buildings. It would be quite unusual for a home to have three-phase power. It is possible to install a phase converter to convert single-phase to three-phase, but I doubt that it would be economically practical.
  3. CarlH

    CarlH New Member

    Messages:
    175
    Location:
    Northern VA
    Probably not. As far as I know a typical residence is supplied by a single phase. And in case anybody mentions it, 240V at your residence is not two phase or two parts of three phase. It is still single phase. If I remember correctly, there are one phase to three phase converters, but they are not likely to be practical or economical. Single to three phase converters.

    That 33amp requirement may be another problem too.
  4. Speedy Petey

    Speedy Petey Licensed Electrical Contractor

    Messages:
    1,016
    Location:
    NY State, USA
    Why is that???
    The rest of your post is valid, this statement not so much.


    Molo, unless this thing is gold plated and you're getting it for free, there is no way it would be worth the expense and effort to use it with a phase converter.
  5. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    Maybe what he is asking....and I don't know either.....is how does the KW of something drawing 33 amps ~ 3 phase compare to say a 30 amp single phase 240 dryer or water heater. In other words, is the KW rating of that commercial dryer going to exceed the power available in his house?? Fill us in on that comparison.
  6. CarlH

    CarlH New Member

    Messages:
    175
    Location:
    Northern VA
    I said may be a problem. Don't know for sure. This is definitely different from supplying 30amps to a single phase dryer. How big and how much is it going to cost for a single phase to three phase converter that can deliver 33amps? In other words, this is different than trying to run something like a three phase table saw on single phase. I don't know how efficient single phase to three phase converter is, but I would expect it to draw more than 33amps to supply the dryer. I am not an electrician and have no direct experience with these converters. What do you think?
  7. Speedy Petey

    Speedy Petey Licensed Electrical Contractor

    Messages:
    1,016
    Location:
    NY State, USA
    It is really no different at all other than the draw, but you are right. :)
    It could be done with a 200A service that was not loaded to capacity, but WHY bother?

    That was my point about it being prohibitive in several ways.
  8. Billy_Bob

    Billy_Bob In the Trades

    Messages:
    422
    I think I recall reading (for at least one brand - forget which...) that commercial washers/dryers come in three phase or single phase if buying new.
  9. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    I have some familiarity with the Milnor commercial line. Basically any model can be ordered as single or 3 phase, 240, 480, etc.
  10. molo

    molo Member

    Messages:
    864
    Location:
    cold new york
    In More Detail; this is a used, commercial, coin operated Speedqueen dryer.

    I want the washing machines that this person is selling, but he wants me to take the dryers as well. I am waiting to hear back from the electric utility company about where 3-phase is even available around here. There are some roads that don't have 3-phase available.

    Thanks for any replies,
  11. Speedy Petey

    Speedy Petey Licensed Electrical Contractor

    Messages:
    1,016
    Location:
    NY State, USA
    So if you could, you would have your service upgraded to 3-phase just to have this dryer installed. :confused:
  12. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,304
    Location:
    Cave Creek, Arizona
    3 phase

    In Phoenix there are areas with residential 3 phase wiring, and some residents, such as a friend of mine, will not move because they like having it. A three phase dryer, might have a single phase motor with elements wired in a 3 phase sequence.
  13. molo

    molo Member

    Messages:
    864
    Location:
    cold new york
    Not that I want to put this into my house. I used my house as an example. Just trying to determine the trouble someone would have to go through to put one of these in their homes around here.
    There is 3-phase available at the colleges and at an industrial park, but I've got a call into the utility to see if it is available on most streets in town. I really have no idea.

    Thanks for any replies,
  14. maintenanceguy

    maintenanceguy In the Trades

    Messages:
    107
    Location:
    Pennsylvania
    all of the commercial dryers I've worked on (I've actually worked on quite a few) had gas fired burners with single phase controls. Only the motor was 3 phase. I'm sure a single phase motor could be gotten, or the existing motor could be rewired or rewound to work on single phase.

    But still probably not worth the expense.
  15. molo

    molo Member

    Messages:
    864
    Location:
    cold new york
    Anybody want a 3-phase, coin operated, electric dryer? :)
    I Heard back from the utility, and there is 3-phase available at a location I might be interested in.BUT, they would need to mount a transformer and run wire over to the house. That's going to cost a bit of change. That's opnly getting the power to the house, and then it needs to be wired into the home.
    Yikes.

    And I just got off the phone with speedqueen again and they do require 3-phase.
  16. alternety

    alternety Like an engineer

    Messages:
    671
    Location:
    Washington
    At any given location, look at the hot distribution wires on the power pole. If there is one - single phase. If there are three - three phase is available.

    The guy up the street from me has three transformers on the pole to supply his three phase power. He is also the last one on the street that has it available. The power company had to upgrade all the poles back to the nearest 3 phase feeder.

    Unless the three phase is already available on the pole, the costs could be extraordinary.
  17. molo

    molo Member

    Messages:
    864
    Location:
    cold new york
    Hi Alternety,
    I learned from the utility company that there even if three-phase is at the pole the costs could still be high. For example, I would have to pay the labor fro them to install a transformer and a service line to the house. Then I have to hire the electrician to get it into the house so I could plug the dryer in. I think that will start to get expensive, perhaps in the 2-3k range. It might make sense if I were doing a laundromat. But 2-3k (if that's accurate) is a bit high to be able to plug in a dryer. Do you guys think my estimate is close?
  18. alternety

    alternety Like an engineer

    Messages:
    671
    Location:
    Washington
    My point was that if 3 phase was not at the pole there were costs in ADDITION to the ones you were already aware of. The following information is drawn from real old parts of my brain. I am not a power guy (and I really hated the motors course).

    In figuring cost if it is on the pole:

    A new drop from the pole will be needed. Leave the old service in place and add the 3 phase drop. You are still going to need single phase for everything else. If you don't do it this way you will have to have a large transformer in the house/building to generate single phase. There are a number of permutations for obtaining single phase from the three phase but the transformer is probably the best. Amongst other things, three phase is going to be 208 V. The power company can supply it as three wire or three wire and neutral.

    Is the drop aerial or buried. In any case you will need a new entrance panel/disconnect and breaker panel, and meter box. Your electrician should be familiar with the concept of "phase order". For non-resistive loads it matters.

    As you noted, you will also then need the wiring routed to the load.

    You have to really really want to use three phase to pay for all of this. If you really want to do this I would suggest just seeing what it would cost to just replace the appropriate pieces of the dryer. I suspect it may be cost effective to simply buy other dryers. The advantages of three phase are smaller wires (for the same load) and more efficient motor operation.
  19. Norcal01

    Norcal01 New Member

    Messages:
    23
    Why would anyone use anything but gas for a commercial dryer, gas(natural) is usually more economical then electricity, but that does assume that natural gas is avail. On a second note depending the utility, voltage could be 120/240V 3Ø or 208Y/120V 3Ø one cannot automatically assume they will supply 208V.
  20. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,304
    Location:
    Cave Creek, Arizona
    wires

    Australia may use a single wire, and it is 240 volts, but everywhere in the USA has three wires for single phase 120/240, or 4 wires for three phase.

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