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  1. #1
    Join Date
    Aug 2006
    Location
    Columbus Ohio
    Posts
    1,980

    VFD on an Air Raid Siren?

    I have a buddy who is a volunteer firefighter, his department is looking to get rid of a old air raid siren that they sound anytime there is a fire call, it's kind of a tradition in volunteer FD's. They claim it costs too much to sound the thing. I suppose they are looking to "go green" with a electronic speaker siren.

    I suggested putting a VFD on it to help with the cost but the more I think about it it may end up distorting the sound only running at say 75% of speed and once you go to 100% you aren't really saving much.

    What says the hive?

    Video of a like siren.

    http://www.youtube.com/watch?v=h6D6XP_F5PY
    UA LU189

    10mm, because it's better than .45acp

  2. #2
    Join Date
    Jan 2005
    Location
    steeler nation
    Posts
    2,045
    i dont know if it would work but i would love to try it!
    IV IV IX

    use your head for something other than a hat rack.......Gerry

  3. #3
    Join Date
    May 2011
    Location
    North FL.
    Posts
    204
    Sounds like a York air cooled chiller. Screw compressors on a drive that run up to 200 hertz

  4. #4
    Join Date
    Feb 2012
    Location
    Upstate SC
    Posts
    84
    I am aware of a situation like this, however it was the fact that it was a three phase motor and it was the minimum power company charge that was costing them so much and not the actual usage.

  5. #5
    Join Date
    Aug 2006
    Location
    Columbus Ohio
    Posts
    1,980
    Quote Originally Posted by jburchstead View Post
    I am aware of a situation like this, however it was the fact that it was a three phase motor and it was the minimum power company charge that was costing them so much and not the actual usage.
    Ahhh... I never tonight of that. I am not sure if that is the issue or not?
    UA LU189

    10mm, because it's better than .45acp

  6. #6
    Join Date
    May 2011
    Location
    North FL.
    Posts
    204
    Could you use single phase power and install a VSD and use it to create your 3 phase power source??? To avoid power charges?

  7. #7
    Join Date
    Mar 2010
    Location
    Kent, WA.
    Posts
    184
    Quote Originally Posted by henpeck View Post
    Could you use single phase power and install a VSD and use it to create your 3 phase power source??? To avoid power charges?
    Yes you can use a VFD on single phase to create 3 phase. I think the ABB guidline is at least a 50% derate. so if you have a 5 hp motor you would need a 10hp drive for it to work.
    Experience
    Is what you get when you didn't get what you wanted.

    A positive attidude will not solve all your problems, but it will annoy enough people to make it worthwhile.

  8. #8
    Join Date
    Mar 2003
    Posts
    7,321
    check with your utility to see if you can get a rebate for installing the vfd, lol.

  9. #9
    Join Date
    Jul 2001
    Location
    Southern NJ
    Posts
    1,241
    If it draws 100 amps at 240V for 3 minutes, that's 1.2KWH for each fire. at $.13 a KWH, that's about 16 cents for each fire.

    I think the fire sirens are a nuisance now that we have other ways to communicate but if the FD doesn't mind annoying the neighbors in the name of tradition, run the siren they have.
    Ryan
    Maintenance Guy
    -----------------
    naysayer, skeptic, conspiracy theorist

  10. #10
    Join Date
    Jun 2010
    Location
    Southwest NM
    Posts
    22

    Feeding a VFD with single phase power

    Quote Originally Posted by hotrodrob View Post
    Yes you can use a VFD on single phase to create 3 phase. I think the ABB guidline is at least a 50% derate
    Just be sure there's no hard-wired phase failure shutdown in the VFD firmware. Most anything 3HP or less comes equipped for single phase input (rectifier diodes rated for at least 1.73x input current, no phase failure shutdown.) Gets a little tougher at 5HP - the Hitachi's we used to use were discontinued a couple years back.

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