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Thread: Three phase question.....

  1. #1
    Join Date
    Aug 2010
    Posts
    31

    Three phase question.....

    I know the most common/modern three phase arrangement is a 208 volt wye, my building has a 240 volt delta arrangement. Anyone else have this set up or used it? The way I understand it is the 240 three phase is usable, just not as common. The power company is working up the numbers to switch to 208. If using the three phase as is will create headaches and conversion is too expensive I can run the elements on 240 single phase.

    Any experiences appreciated
    Craig.

  2. #2
    Join Date
    Nov 2009
    Location
    Moab, Utah
    Posts
    496

    Service Types

    Quote Originally Posted by Craig Dhonau View Post
    I know the most common/modern three phase arrangement is a 208 volt wye, my building has a 240 volt delta arrangement. Anyone else have this set up or used it? The way I understand it is the 240 three phase is usable, just not as common. The power company is working up the numbers to switch to 208. If using the three phase as is will create headaches and conversion is too expensive I can run the elements on 240 single phase.

    Any experiences appreciated
    Craig.
    There are different types of Delta configurations. Most commonly you will have a high leg as referenced to Neutral on one phase if you have 240-120V Service at the panel.
    This type of service is intolerant of shade tree electricians.
    The main problem is a lot of single phase loads will imbalance the service for 3 phase as you can only land them on 2 phases in the distribution panel. The best thing is to get with a Master Electrician on your proposed panel load schedule and get his input. This will require you get fairly detailed in writing down all your loads as required by a POCO load sheet. Everything gets converted into watts. Its not necessarily a fun exercise, and needs to include everything along with possible future additions.
    Warren Turner
    Industrial Engineering Technician
    HVACR-Electrical Systems Specialist
    Moab Brewery
    " No Cell Phone Zone."

  3. #3
    Join Date
    Aug 2010
    Posts
    31
    Warren,
    Thanks for the information. The electrician I’ve spoken to made many of the same points; it seems the imbalancing effect may negate some three phase advantages. I’ll wait and see what the power company says.
    Thanks again,
    Craig.

  4. #4
    Join Date
    Aug 2010
    Location
    Enterprise, Oregon
    Posts
    1,812
    We've been running for 20+ years on a 240V Delta feed. We pay an off-set for phase adjustment, but our electric bill requires a couple of lawyers, an accountant, a seer and an astrologer to decode so I don't know how much it costs.

    As for running most equipment, it's fine. Resistive loads (heating elements) have to be rated for the 240V or they will draw significantly more amperage than rated. We ran 3-phase heating element arrays wired as Delta for years with no problems. Almost all 3-phase motors can be configured for either 208 or 240 V or simply don't care. A VFD doesn't care. You do have to be wary of that high leg--we have one breaker box (wired by a PO) which has the high leg wired to the wrong buss, and this has lead to a couple of small disasters over the years. Most things designed for 120V don't like running on 240V!
    Timm Turrentine

    Brewerywright,
    Terminal Gravity Brewing,
    Enterprise. Oregon.

  5. #5
    Join Date
    Aug 2010
    Posts
    31
    Thanks Timm,
    Good to hear no problems with the 240v delta set up. I guess I’ll wait a few days and see what the electric company and the electrician say. With a small set up, I don’t think it’ll be a huge factor on power consumption. As for the power company Ouiji Board billing methods.....
    Craig

  6. #6
    Join Date
    Nov 2009
    Location
    Moab, Utah
    Posts
    496

    On the Star patterns

    Quote Originally Posted by TGTimm View Post
    We've been running for 20+ years on a 240V Delta feed. We pay an off-set for phase adjustment, but our electric bill requires a couple of lawyers, an accountant, a seer and an astrologer to decode so I don't know how much it costs.

    As for running most equipment, it's fine. Resistive loads (heating elements) have to be rated for the 240V or they will draw significantly more amperage than rated. We ran 3-phase heating element arrays wired as Delta for years with no problems. Almost all 3-phase motors can be configured for either 208 or 240 V or simply don't care. A VFD doesn't care. You do have to be wary of that high leg--we have one breaker box (wired by a PO) which has the high leg wired to the wrong buss, and this has lead to a couple of small disasters over the years. Most things designed for 120V don't like running on 240V!
    Timm, I am glad to see you have an awareness of the Astrology, as it hits machinery Ultra Hard 3x/year when mercury goes retrograde. What people do not seem to get is that we are in an " Electric " universe and machinery as well as humans are subject to those forces, both EM, and others that are much well less understood. Take note that all Solid State Technology will continue to become more unstable as we move forward in the Time Line. The seeming laws of Physics that are thought to be immutable are in a state of " transition."
    This is a good thing.
    The Sun is an Electric Body. It is not burning anything, and there is only Fusion in the flares, which are a different matter altogether........
    Warren Turner
    Industrial Engineering Technician
    HVACR-Electrical Systems Specialist
    Moab Brewery
    " No Cell Phone Zone."

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