Why Microwave oven transformer is welded?

[MrAl]

Hello again,

Ok thanks for your input on this. I am not sure when i will get to try it though, may take a while.
I figure also i'll have to use a watt meter to monitor the input power so i know how to adjust it. I noticed as the line voltage goes down the input power goes down and the cooking power goes down. Should be interesting though.

One thing i noticed about the Panasonic is that with the lower power 'continuous' power it cooks the food better in that the meats dont get as tough this way. I would think a regular microwave oven with lowered cooking power would do the same when the power is still continuous.

 

[tcmtech]

I figure also i'll have to use a watt meter to monitor the input power so i know how to adjust it. I noticed as the line voltage goes down the input power goes down and the cooking power goes down. Should be interesting though.

I don't follow the logic.

What's wrong with just using a transformer of one type or another to step the low line voltage back up into the range that the microwave oven is specced to work in?
As in using a basic buck/boost autotransformer to bring your 90 - 100 VAC back up to the 110 - 130 VAC that the unit needs to work properly?

Why all the unnecessary run around when a basic multimeter to figure out what input to output winding ratios are needed is more than sufficient?

Which BTW, a common 120:16/32 buck-boost transformer configured as a boosting auto transformer would give you two voltage boosting points to work with as your primary line voltage drops by simply stacking the two 16 volt windings in series on top of the primary winding thus allowing you to boost 100 - 110 VAC to 113 - 125 volts at the midpoint tap and 87 - 100 VAC to 110 - 125 volts at the end point tap.
Also being the transformer only has to handle the current at the step up voltage difference a 500 VA unit would easily handle a 1500 watt load all day without issue even at the lowest 87-volt input level.

120/240:16/32 volt 500 VA transformers can be found all over the place for around ~$80 - $100 online. Or you can make your own out of an old 15 - 20 amp rated battery charger transformer too by stacking the secondary windings in series with the primary.

 

[MrAl]

I don't follow the logic.

What's wrong with just using a transformer of one type or another to step the low line voltage back up into the range that the microwave oven is specced to work in?
As in using a basic buck/boost autotransformer to bring your 90 - 100 VAC back up to the 110 - 130 VAC that the unit needs to work properly?

Why all the unnecessary run around when a basic multimeter to figure out what input to output winding ratios are needed is more than sufficient?

Which BTW, a common 120:16/32 buck-boost transformer configured as a boosting auto transformer would give you two voltage boosting points to work with as your primary line voltage drops by simply stacking the two 16 volt windings in series on top of the primary winding thus allowing you to boost 100 - 110 VAC to 113 - 125 volts at the midpoint tap and 87 - 100 VAC to 110 - 125 volts at the end point tap.
Also being the transformer only has to handle the current at the step up voltage difference a 500 VA unit would easily handle a 1500 watt load all day without issue even at the lowest 87-volt input level.

120/240:16/32 volt 500 VA transformers can be found all over the place for around ~$80 - $100 online. Or you can make your own out of an old 15 - 20 amp rated battery charger transformer too by stacking the secondary windings in series with the primary.

Hi there,

Thanks for the reply but i am afraid that you misinterpreted my intentions for this particular discussion.
This discussion was not about boosting the line voltage from 100v to 120v to get the oven to work properly. It was about 'adjusting' the 120v line down to maybe 90v to 120v (completely variable with a variac) in order to DECREASE the power going into the microwave oven.
The main idea here is to be able to set the microwave oven on 'high' yet cook at lower power levels. The reason for doing this is because when a standard mic oven is turned down to say power level '5', it pulses on and off at maybe a 50 percent duty cycle, once every 10 to 20 seconds. To avoid that, i was hoping to set it on high and then use the variac to adjust the input power down and thus set the power level manually.
The reason i believe this would work is because when i observed the line voltage naturally falling to maybe 90v in the summer time, i see the standard oven cooking much slower. The slower cooking however is sometimes desirable as the meats cook better with less dry out and more tender for example.

But yes ways to improve the line voltage here is also interesting.

 

[tcmtech]

Thanks for the reply but i am afraid that you misinterpreted my intentions for this particular discussion.
This discussion was not about boosting the line voltage from 100v to 120v to get the oven to work properly. It was about 'adjusting' the 120v line down to maybe 90v to 120v (completely variable with a variac) in order to DECREASE the power going into the microwave oven.
The main idea here is to be able to set the microwave oven on 'high' yet cook at lower power levels. The reason for doing this is because when a standard mic oven is turned down to say power level '5', it pulses on and off at maybe a 50 percent duty cycle, once every 10 to 20 seconds. To avoid that, i was hoping to set it on high and then use the variac to adjust the input power down and thus set the power level manually.

You have too much time on your hands if your concerned about how your microwave functions while it cooks.