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# I was just wondering if this can drive a motor if i replace the transistor with mosfets? Answered

i want to power a 100w 220V~ motor with this circuit. what will happen if i replace the 2 transistors with an irfp250n with this circuit. i am pretty new to electronics. there are another things that i want to power with this thing. i will be using a rewound MOT. is there a way to convert this circuit current output from square wave to a sinus wave.

the 1k resistor will be changed to 100R ones.

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## 6 Replies

iceng (author)2011-04-10

Some things to consider in using a transformer, the rough transfer ratio 12V to 220V is about 18:1..

If you draw a 100 watt load the current is .45A at 220V and when reflected back to the 12V side is 8A per semiconductor for half the time.

If you draw a1000 watt load the current is ten more 4.5A at 220V and reflected back to the 12V side is 81A per semiconductor for half the time.

Neither of the loads can be done using the 2N6121 by-polar transistors only. The 2N6121 good for mostly 4A with a gain ( hfe ) of only ten.

The 30A MosFet idea can handle the smaller 100W load but no-way a 1000W drill.
Don't forget heat-sink cooling the semiconductors.

Now, the power aspect of the control transformer, I like Stancor the P-6379 is an 8lb monster that could barely do the 12V 8A input to 230V output conversion.

A transformer for more power is not easily available. You may have to run several in parallel and consider what 80 amps will do to a little old 12V battery.

I would start to consider a rechargeable portable tool.

A

lemonie (author)2011-04-10

You want to power a 100w 220V~ motor with this circuit?
It only outputs 12V, what have you actually got and is the motor AC or DC?

L

rickharris (author)2011-04-10

It all depends on the transformer. The transistors are providing an AC current into the primary of the transformer so it can raise the voltage - BUT this will at the same time reduce the current. (nothing for nothing).

The motor will draw current from the secondary so the transformer must be rated to meet your requirements.

in addition the motor will more than likely expect 50 or 60 Hz (cycles) and this set up might well not be giving that.

All in all I think I would go out and buy a suitable inverter.

ARJOON (author)2011-04-10

i think that you're wrong here. a MOT is rated about 1000W of power. and judging from the circuit, the transistors are not giving enough power. in the datasheet in maximum ratings the transistor can switch upto 65W of power. that is why he is asking if it will work if he uses 2mosfet(220W).
Therefore from this link it says it gives different frequency about RC change. What is this RC?

and for the mosfet idk. this link below gives part of information

http://www.eleccircuit.com/micro-inverter-by-2n5121/

rickharris (author)2011-04-10

Your right about the MOT - I didn't read that far!

Bet it still won't work without a lot of messing around.

To make the C part of the RC it needs 2 suitable capacitors in the base circuits.

ARJOON (author)2011-04-10

how about using mosfets this is also interesting me