# What size generator do I need....



## Julie798 (Jan 10, 2010)

Hi

Can anyone tell me what size generator do I need to run a 700 watt microwave, and do I need to run it through an invertor, so invertor plugged in to genny and microwave plugged into invertor ! 
Sorry if its a simple question to some, but I am clueless 

Thanks !


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## Deleted member 5759 (Jan 10, 2010)

Depends on the wattage of the microwave, eg 800watt you need a 1KW aprox genny and you dont need an inverter unless the m/w runs on 12v DC

Most microwave ovens are 240v AC

There are some cheapo gennys about but be carefull as they can damage electronic stuff like laptops, tv's etc

There are some Planet gennys on our website that will be perfectly safe, quiet, portable but not cheap!

Peter


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## derekfaeberwick (Jan 10, 2010)

JohnsCrossMotorHomes said:


> Depends on the wattage of the microwave, eg 800watt you need a 1KW aprox genny and you dont need an inverter unless the m/w runs on 12v DC
> 
> Most microwave ovens are 240v AC
> 
> ...




  Sorry but I disagree. A 2 kw genny would be needed for a 700 w microwave.

  700 is the output, the input during start up is about twice the output, about 13-1400 watts.


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## Deleted member 5759 (Jan 10, 2010)

Thanks Derek,

I stand corrected! mind you I meant to add, buy the biggest you can afford!

Peter


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## lenny (Jan 10, 2010)

Julie798 said:


> Hi
> 
> Can anyone tell me what size generator do I need to run a 700 watt microwave, and do I need to run it through an invertor, so invertor plugged in to genny and microwave plugged into invertor !
> Sorry if its a simple question to some, but I am clueless
> ...



Hiya Julie, why dont you PM" rickboy" with this query, he,s a whizz on generators

http://www.wildcamping.co.uk/forums/general-chat/8329-stir-crazy.html#post82236

Just joking Julie, It,s just that time of the year


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## ajs (Jan 11, 2010)

Julie798 said:


> Hi
> 
> Can anyone tell me what size generator do I need to run a 700 watt microwave, and do I need to run it through an invertor, so invertor plugged in to genny and microwave plugged into invertor !
> Sorry if its a simple question to some, but I am clueless
> ...


 

whish i had asked this question
... tried mine plugged into 240 system... nope.. genny cut out
tried it plugged into inverter... nope.. genny cut out.

made me wonder... 
what the frigginbell do i have a genny for if it won’t even power a microwave.



regards
aj


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## coolasluck (Jan 11, 2010)

ajs said:


> whish i had asked this question
> ... tried mine plugged into 240 system... nope.. genny cut out
> tried it plugged into inverter... nope.. genny cut out.
> 
> ...









answer is that you get them to power hairdryers and hair straighteners for her indoors.Im lucky im as bold as you AJ.


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## bigboack (Jan 11, 2010)

Onan 2.5 KW (2500watts) Built in to the motorhome, powers microwave, tv and lights, all at the same time, Bit noisy though as the silencer fell off it in June.Also charges the battery, nice bit of kit, It runs off GAS also.


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## robjmckinney (Jan 11, 2010)

*Around 10 amps so 2 to 2.5KW*

The microwave does tend to draw considerable power and can have a spike when the magnetron is energised by the combination of transformer, diode and capacitor to produce 2500 volts, all magnetrons require such voltage to work. Maplins does supply a 12 volt microwave oven that uses a heavy duty power supply through the cigerette socket.

So anyone choosing a generator or inverter should be looking at 2000 watts plus. Try using a manual clock version, not touch control microwave, obviously cheap means low power in general and you may find 8 amps or slightly less is used during operation!


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## ajs (Jan 11, 2010)

robjmckinney said:


> The microwave does tend to draw considerable power and can have a spike when the magnetron is energised by the combination of transformer, diode and capacitor to produce 2500 volts, all magnetrons require such voltage to work. Maplins does supply a 12 volt microwave oven that uses a heavy duty power supply through the cigerette socket.
> 
> So anyone choosing a generator or inverter should be looking at 2000 watts plus. Try using a manual clock version, not touch control microwave, obviously cheap means low power in general and you may find 8 amps or slightly less is used during operation!


 


errr yes... i think..... _did i understand that _



my problem is ....i think.... i have an 800w m/wave
and a 600w inverter.


micro works.... takes 3 times longer to cook anything but before it has the batterys flat.


something not quite right ....
mind you.. she bought me some srewdrivers for xmas 
so now i'm realy dangerous

regards
aj


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## derekfaeberwick (Jan 12, 2010)

ajs said:


> errr yes... i think..... _did i understand that _
> 
> 
> 
> ...




  50 Watt inverter should sort you out for your hair drying requirements and 50 cc in a bike should sort out your licence retention problems, simples.


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## robjmckinney (Jan 12, 2010)

*800w m/wave*

The microwave does not alter output by varying the power, it is simply on or off. To get the variation in power levels it simply turns off for part of the cooking time. Half power, simply off for half the time, quarter power off three quarters of the time. The magnetron needs 2500 volts to operate, any less it will not energise so will not work!

There is no difference to the simple fact of the required 2500 volts, to get more power for say a commercial microwaves they simply multiply the magnetrons to improve power output. For a large commercial may have four magnetrons. The most variation you get from manufacturers is touch controls and additional components like grill or oven.

They use fast blow fuses inside normally around 6.3 amp (Sharp), 8 and 10 amp for most other makes. These are quite different to normal fuses which blow at nearly twice their rating, fast blowing blow more or less at their rating. 

So your 600 watt inverter would be certainly struggling and may fail over a long period of use. You may be lucky if your inverter manufacturer makes various sizes, your particular model may be a larger power output with a 600 watt label. This happens a lot in industry as it is to expensive to supply such variation in power in appliances. For example spin speed variations on washing machines were simply minor adjustments of speed control otherwise washing machines were exactly the same internally. Cheaper models having less programs have the same parts but less choice on dial. Outboard motors models are similar to look at but different power outputs had a simple screw restricting the power on smaller hp models.

Not always the case but no doubt the public would be suprised how much the case this occured in industry!


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## ajs (Jan 12, 2010)

robjmckinney said:


> So your 600 watt inverter would be certainly struggling and may fail over a long period of use.



 errr fanks... so i change the inverter then..

 regards
aj


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## robjmckinney (Jan 12, 2010)

*Why change if it works for you!*

If it works, why not simply run the engine while using the microwave!

Your alternator pushes out some 90 amps and you don't run your microwave oven all day!


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## degzie (Jan 13, 2010)

will this do lol


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