On Board Microwaves

Hi.  Can anybody help with this one.  We have a Daewoo microwave oven fitted in our 2008 Bailey Pageant Majestic.  It works perfectly well for the first cooking spell but then cuts out when trying to start another meal.  The first time this happened I checked connections, fuses etc which were all ok.  After some time (probably about 5 minutes) the oven works again.  There is no problem with the door mechanisim.  I wonder if there is some sort of cut out device built into the oven and, if so, why might it be cutting out?  My caravan manual offers no clue.  Anyone else had similar problems?