Instructables

How to: High current Microwave oven Transformer

Step 2: Adding in new secondary and the Final product. (VIDEO)

Now the last part! this was easy wasn't it..?

Step 1) Now that you have removed the secondary windings, shunts and filament windings and its as tidy as possible, you can take your new secondary wire (whatever gauge your using) and wind as many turns as possible on your transformer as you can fit, the more turns the more volts. and the thicker the wire the more current you will get. to wind the new secondary, just wrap your new wire round the core of the transformer where the old secondary was.

Step 2) Now you can attach whatever you want to your new secondary's two output leads, whether it be some big heavy duty alligator clamps or connecting it up for use as a spot welder or stick welder 

Step 3) Get your 3 pin grounded wall plug and connect the ground to the base of your transformer, and the hot wire and the neutral wire to your transformers primary inputs.

Step 4) Plug it in, turn it on and you have yourself a power supply that theoretically should be able to supply up too a kilowatt of raw output power! 

And of course a video. 2-3 turns approx 3v AC and around 500 amps of steel melting power...



Heres a snapshot of one rewound MOT i put a bit more effort into. I wound it into a power supply that has 5 voltage taps which once rectified the voltage on each is 0v (GND), 12v, 24v, 30v and 50v DC! all of the voltages besides the 50v can put out 30 amps+ and the 50v limited to around 20 amps.
 
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stuffdone1 year ago
Says VIDEO DOES NOT EXIST?
charlieb0003 years ago
question!
does that work (heating of nails and screwdrivers) if the secondary was left at 2000v?

if not then why? the same input power is consumed....
i guess the secondary would burn....
as well as the primary, when i shorted out my mot the primary got hotter than the secondary.
HazzWold1993 (author)  charlieb0003 years ago
yeah
HazzWold1993 (author)  charlieb0003 years ago
When the output is at 2000vac the output current is around 400mA on a standard 1000watt MOT which isnt enough to heat resistive elements like a nail. even some batterys have up to 1200mA
HazzWold1993 (author)  charlieb0003 years ago
it wont work because the output on the secondary is a balance between voltage and current, the more voltage you want, the more turns you must use but the less current you get, and vice versa. and by lowering the amount of turns to 2 for example like shown above ^ you only get 2.4vac (1.2vac per turn in areas running on 240v) but you get about 500amps + (measure on a clamp meter) but the more turns you add the higher the voltage gets and the lower the current gets. hope this helps