Converting 5V DC to 120 or 230 V AC

Discussion in 'General Electronics Chat' started by NewCurly, Jun 12, 2016.

1. NewCurly Thread Starter New Member

Mar 20, 2016
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0
Hi,

I am new to circuits and I am working with converting 5V DC to 120 or 230 V AC for powering a motor. Following is the circuit that I am using: http://www.sentex.ca/~mec1995/circ/555dcac.html

And I am using a 6-0-6 AC to DC Transformer and connected the secondary coil to the circuit. The supply power is 5V DC and 500 milli amps and I am not getting any out from the transformer. I measured the AC voltage after the Inductor L1 which is 0V and also measured the AC voltage in 3rd pin of 555 timer and before the C4 capacitor which reads as 7 to 8 V AC.

Please can some one tell me whether I am providing less power to the circuit or is there something that I am doing wrong. The C4 capacitor is
2700uF 25V and the L1 is 1uH.

Thanks

2. tracecom AAC Fanatic!

Apr 16, 2010
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I don't really understand what transformer you are using, but I think that may be the problem. You need a step up filament transformer.

3. NewCurly Thread Starter New Member

Mar 20, 2016
16
0
I am using the following listed transformer.

http://robocraze.com/6-0-6-transformer-500ma.html

But my concern is I am getting 0V after the Inductor L1.

Thanks

4. NewCurly Thread Starter New Member

Mar 20, 2016
16
0
I will also check for a filament step up transformer.

5. bushrat Member

Nov 29, 2014
209
58
Hi NewCurly,
Transformer (step-down or step-up) transfers power from one side to another. You can step up voltage thousands of times, but power on both sides must be same. So if you want to make 230VAC on output side of transformer and enough power to run a motor, it will come as a suprise that it will not work. For example, if the motor takes 1 A to run at 230VAC, that's 230 Watts (230V X 1A = 230W). This means that you will also need to have 230W on the input. If your input is 5V, then you will need to have 46A of current on your input side (230W / 5V = 46A). I don't think you have components that can handle this much current.

While circuits like this show what can be accomplished with electronics, they are not the greatest of ideas to build blindly.

6. Alec_t AAC Fanatic!

Sep 17, 2013
9,444
2,288
The voltages and currents in your circuit are not sinusoidal, so your meter doesn't give accurate AC measurements. If the supply voltage is 5VDC, then 7-8VAC cannot be present at the 555's pin 3 or before C4.

Last edited: Jun 12, 2016
7. NewCurly Thread Starter New Member

Mar 20, 2016
16
0
Thanks for the inputs and the video. But I am not getting an output from the transformer.
Following links provide the motors that i am planning to use : http://www.elimomotors.com/induction-motors-25-watt.html

8. bushrat Member

Nov 29, 2014
209
58
48 W motor, so that will be 10A minimum from your 5V power supply. Hopefully you have that covered.
Ok, getting back to your circuit, do you have oscilloscope? If yes, used it.
Remove transformer, and see if you have sine wave (or in your case square wave) before and after L1. and C4. What's the voltage P-P of your signal?
Can Q1 and Q2 handle 10A? (datasheet says no link ) That's still a lot of power for a 5V circuit.. you are running a risk of overheating or burning something.. Is there any way you can get another source of power for your project?

Last edited: Jun 12, 2016
9. BobTPH Senior Member

Jun 5, 2013
1,439
332
Okay, that is a quite small motor. But still, 0.4A at 120V is 48W. You need almost 10A at 5V to run this.

Bob

10. NewCurly Thread Starter New Member

Mar 20, 2016
16
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Hi,

If the circuit I have linked in my first message is not correct or appropriate, wondering if someone can provide me with a circuit that can help me convert a low voltage DC to 120 or 230 V AC.

I read some content in a webpage which mentioned about converting a 1V 500 milli amp DC into a considerable power using DC to DC converter and then converting it to AC for use, also would like to know whether that's possible.

Thanks

11. bushrat Member

Nov 29, 2014
209
58
No matter what circuit you build, you must remember that you cannot create energy, only convert it. Any power out, must equal power in (plus heat loss, and few other things). So basically, you must put in more power that you can take out.
If you want to convert low DC into AC, the simplest option i can think of is car battery and one of the DC-to-AC converters that can handle higher wattage than what your device requires.

Nov 4, 2013
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13. Alec_t AAC Fanatic!

Sep 17, 2013
9,444
2,288
Do the sums. Maximum input power there is 1V x 0.5A = 0.5W. So the output power at higher voltage would probably be less than 0.4W. Is that "considerable"?

14. KeepItSimpleStupid AAC Fanatic!

Mar 4, 2014
3,154
566
there's a whole bunch of considerations in this project, the big one is:

Vp*Ip=Vs*Is

primarys and secondaries can be reversed with an efficiency penalty, You can't exceed the designed I on either side.

I is an RMS current. Your meter may be average responding, RMS reading. It assumes a sine wave as the input.

Motors also need a LOT more current to start. They are usually rated in VA or Volts*Amps. It could be 4x the normal running current.

Then there is wave shape.

For higher power applications, a center-tapped transformer is usually used with the center tap at +V and the ends switched to ground 180 deg out of phase.

I successfully designed one for a friend to operate a small synchronous motor for his telescope. He built it and it worked fine.

I suspect you killed the transformer. Check the resistance of the primary and secondary.

15. BobTPH Senior Member

Jun 5, 2013
1,439
332
With a 5V, 500mA supply? I doubt it.

Bob

16. mcgyvr AAC Fanatic!

Oct 15, 2009
5,394
1,194

Your power supply is 5V @500mA which equals 2.5 Watts of power..
Your motor requires 110V @400mA which equals 44 Watts of power..

You will NEVER be able to run the motor no matter what circuit you have as you only have 2.5 Watts of power and need 44 watts
NO circuit can make more "watts" than you have to start with..

You can change the voltage/current but you can't make more WATTS.. plain and simple..

17. NewCurly Thread Starter New Member

Mar 20, 2016
16
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Thanks for all your inputs and suggestions.

The inputs where valuable and time saving.

18. Tonyr1084 Distinguished Member

Sep 24, 2015
2,911
656
What will the motor be running?

Not that I think this circuit has a snowball's chance in help. If we know your final goal perhaps we can recommend something better suited to achieve this.

19. NewCurly Thread Starter New Member

Mar 20, 2016
16
0
My plan is to design an agri weeder machine that can be controlled through remote control and can operate by using power from battery. This machine will cut the weed and also maybe slice the ground so it cuts the weed to the roots. But after some calculations about energy stored in batteries and capacity of motors, what I see is a machine can be designed but this machine cannot be operated for a longer period of time.

So I am currently planning to remove the batteries from the device and connect it straight to the main through extension in agri fields, so the device can be used for a longer period of time. But live wire in agri fields is a concern which has to be looked into.

20. mcgyvr AAC Fanatic!

Oct 15, 2009
5,394
1,194
Is "weeder machine" just a tiller?

Why not just use a gas powered motor?