the requirement to run 5.5kw 3phase motor?

Discussion in 'General Electronics Chat' started by jessica3000, May 18, 2011.

  1. jessica3000

    Thread Starter New Member

    May 18, 2011
    4
    0
    hi All, i'm new here... plz help...

    if a 3phase motor with 20.4A 220volt 50hz 5,5kw

    1. what is the minimum power requirement to run that motor ? **1
    2. will 13,200VA source good enought to run that motor ?
    3. some people said, when motor start, it will consume minimum twice as much as the power rating on its label.


    **1 this motor is used in an mixing/blending machine
    if you need the label (spec) of the motor, i could post

    thx for your help...
     
    Last edited: May 18, 2011
  2. GetDeviceInfo

    Senior Member

    Jun 7, 2009
    1,571
    230
    the load will dictate the draw profile. If you don't have a lot of inertia, it will spool up in a realtively short time, decreasing your inrush duration.

    Most of your answers can be found in your local codes. Wire should be #10, your overloads set for the FLA, your overcurrent at 50 amp if a breaker, 60 amp if a non TD fuse, 35 amp if TD. You'll also need a local disconnect. Your trans is 60amp, so your good to go, but make sure it's properly fused as well.

    As always, check your codes. A licensed Electrician is your friend in these cases.
     
  3. gerty

    AAC Fanatic!

    Aug 30, 2007
    1,153
    304
    As advised above, your load will be determined by what you are mixing. Something like dough, which is thick and heavy, will draw more current on start up than something liquid.
     
  4. jessica3000

    Thread Starter New Member

    May 18, 2011
    4
    0
    thx so much bro getDeviceInfo,

    1. how much power needed for 5.5kw in VA ?
    2. source of 13,200 VA good enough ?

    please explain in simple term cause i'm still learning!


    local codes = local technician ?
     
  5. GetDeviceInfo

    Senior Member

    Jun 7, 2009
    1,571
    230
    Watts translate to VA by the powerfactor, which may be stated on the nameplate.

    Inrushes can be quite high, and locked rotor can be up to 6x FLA. But as can been seen, fusing reduces that exposure, protecting your circuit. Overloads protect your motor from overheating due to heavy loads or extended start cycles. Regardless, code dictates that you utilize nameplate data.

    13.2kVA at an output of 220vac, equals a 60amp capacity, to which you would fuse (non TD) your motor, so yes, adequate.

    Codes are national, but local would probably be most cost effective
     
  6. jessica3000

    Thread Starter New Member

    May 18, 2011
    4
    0
    [​IMG]
    the motor (mixer machine) is turn on with no load (container of mixer is empty, no powder)!

    would you look after the laber and give more explanation of
    13.2kVA 220vac 50hz source is adequate ?

    should i try to turn the mixing blade to see if it is locked or not?

    what does non TD and 6x FLA means ?

    thx so much bro, you had been so much help!
     
    Last edited: May 18, 2011
  7. GetDeviceInfo

    Senior Member

    Jun 7, 2009
    1,571
    230
    your 5.5kw is 85.7 % efficient at a pf of .83, so, 5.5kw /.857/.83 = 7.73kva input. Check that with your 220vac * 20.4amps * sqrt 3 = 7.77kw. Close for calculations

    Locked rotor means a stalled motor (no speed, energized). 6x FLA is a general value used to indicate what the motor can draw when at stall. FLA is the Full Load Amperage, when delivering it's rated output, and what is marked on the nameplate, in your case 20.4amps

    When fusing, you have a choice of TimeDelay, or non TimeDelay. A TimeDelay fuse allows an overdraw from rated for a short time period before opening. A Non TimeDelay opens above it's rating. The TimeDelay fuse is commonly used for inductive loads where inrush currents exceed it's running draw.

    If by code, you used a non TimeDelay fuse of 60amps, then anything more would open the fuse. Your transformer, if it is infact 13.2kva at 220vac, will source the 60amps. You could employ a larger transformer, but the fuse wouldn't allow it to be utilized. This is assuming the motor is your only load.

    Are you having problems with this equipment, or why the inquiry, may I ask.
     
  8. jessica3000

    Thread Starter New Member

    May 18, 2011
    4
    0
    when the start button of the mixer is pushed,

    the main circuit breaker BREAKS,...(which is 13,200va 220v 50hz)
    why it is so ?

    what does it means
    delta and star
    regarding of dynamo (motor) ?
    will al motor have delta and star ?
     
  9. GetDeviceInfo

    Senior Member

    Jun 7, 2009
    1,571
    230
    Star and Delta describe the configuration in which the internal windings of the motor are wired. These windings, if the manufacturer of the motor allow, can be rewired to obtain various voltage implementations. Your nameplate indicates a fixed voltage Delta configuration. You likely only have the 3 phase wires for termination.

    Your best bet is to bring in someone qualified. Motors are relatively expense to replace, but a shorted wire is very cheap. Your safety and it's implications don't compare in value.

    Just to be clear though, are you saying that your transformer primary breakers are throwing? What are thier ratings and what is the input voltage? Your overcurrent devices should be coordinated so that the load devices go before the supply devices.
     
    Last edited: May 19, 2011
Loading...