Microwave on low amp supply

Discussion in 'Tech/Mech General' started by JohnH, Mar 12, 2014.

  1. JohnH

    JohnH Funster

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    We are going to an event and the supply is only 6 amp. Is this sufficient to power a low wattage microwave? I cannot remember the formula for working out wattage to amperage etc.
    I ask because that helps determine what we take in the way of food.
    We have never tripped a circuit yet but have only used it on greater amp circuits.
    John
     
  2. Welsh girl

    Welsh girl Funster Life Member

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    I don't use mine on a low amp rating as I think it would trip it.
    I then use the skillet.
    Especially if you can't reset it yourself.
     
  3. Techno

    Techno Funster Life Member

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    Yes it should cope with nothing else on at the same time like fridge and battery charger
     
    Last edited: Mar 12, 2014
  4. pappajohn

    pappajohn Funster Life Member

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    i reckon it may trip even with all other electrical goods turned off.

    A 750watt m/w oven may take 1500watts for a few seconds on startup.

    1500watts = 6.25amps
     
  5. Techno

    Techno Funster Life Member

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    OP said a Low wattage microwave
     
  6. SomeoneElse

    SomeoneElse Funster

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    The 800W microwave fitted in our MH has an input rating of 1250W.
    It runs successfully on our 1500W inverter, during operation the inverter says it is suppling 1.28kW.

    6A x 230V = 1380W, you should be OK on a 6A supply, can you see the rating plate on the microwave?

    Anyone know the powerfactor of a running microwave?

    Gordon
     
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  7. pappajohn

    pappajohn Funster Life Member

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    anything lower than 750watts you might just as well stand the food out under the sun to warm up. :Laughing:
     
  8. pappajohn

    pappajohn Funster Life Member

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    Input current and startup current are different...your calculation only allows 100watts for the startup surge current.

    230v is a european 'harmonised standard' voltage....actual UK voltage is still around 240v.
     
    Last edited: Mar 12, 2014
  9. funflair

    funflair Funster Life Member

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    We are running our 800 watt microwave on 6 amp Spanish volts no problem, as Techno says just make sure other 240 stuff is switched off.

    Martin
     
  10. cmcardle75

    cmcardle75 Read Only Funster

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    Remember that the typical Type B MCB is rated at continuous current. It allows plenty for startup surges already. Indeed, you need 5 times its rated value to be certain of tripping it instantaneously. You can manage double its rating for a period of many seconds.
     
  11. pappajohn

    pappajohn Funster Life Member

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    agreed, but many hookup posts and motorhome fuseboards have type C Breakers.
     
  12. Ed Excel

    Ed Excel Funster

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    The input rating on your M/W includes the turntable motor, light, controls, etc, but not the starting load. Power on start up will be of the order of 1600W. Your inverter is no doubt capable of 3000W, for a short time, so it's going to be happy with your M/W start up load.

    You don't say what size circuit protection supplies the M/W.

    Note: p.f. of a microwave oven on defrost setting can be around 0.5
     
  13. Reallyretired

    Reallyretired Funster

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    If I had a microwave (I took mine out to save space and weight) then I would run it off the inverter. If I had ehu I would use that to recharge the batteries as normal so no risk of blowing the ehu.
     
  14. cmcardle75

    cmcardle75 Read Only Funster

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    A Type C breaker is even harder to trip instantaneously. It has the same thermal trip curve as a Type B, but the instantaneous action is set at a higher multiple.

    Usually reserved for lifts and other devices that expect massive inrush currents. Fitted by campsites to reduce the need to constantly reset the breakers!
     
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