DC to AC convertor

[The Master]

Hi, I have a 1.5/2W 6V AC motor and i need to run it from 12V DC. I know DC to AC convertors exist but the ones ive seen usually deal with 240V. I can regulate the voltage down to 6V DC but i need a component that will convert the DC to AC. Do simple, small convertors like this exist and are they expensive? Ive already searched but i only found the high power ones.

[Archangel]

Hi, I have a 1.5/2W 6V AC motor and i need to run it from 12V DC. I know DC to AC convertors exist but the ones ive seen usually deal with 240V. I can regulate the voltage down to 6V DC but i need a component that will convert the DC to AC. Do simple, small convertors like this exist and are they expensive? Ive already searched but i only found the high power ones.
I am pretty sure you could build one. I used to see circuits for these, often in the electronics magazines, used a 12v ct pri and 6v secondary transformer, a couple of transistors . . called it a multivibrator, I think. Base of Q1 took signal from collector of Q2 and vice versa.

[The Master]

I had an idea involving a 555, transistors and diodes that i think will work. The problem with that method is that i get a square wave instead of the normal AC sine wave. Would that matter to an AC motor?

[Archangel]

I had an idea involving a 555, transistors and diodes that i think will work. The problem with that method is that i get a square wave instead of the normal AC sine wave. Would that matter to an AC motor?

I think motors complain voiceferously to square waves, but a 555 can output various waveforms with a little work, I am pretty sure they brew up function generators using them. http://www.physics.udel.edu/~nowak/phys645/555%20timer%20lab_files/555%20timer%20lab.pdf
http://www.simplecircuitdiagram.com/2009/06/17/sawtooth-wave-signal-generator-using-555-ic/
Why not use a PIC ? You are already good at them, yes?
Oh here is a circuit you might glean some use from project 100 watt . . . http://datasheetreference.com/2n3055-datasheet.html
swap out the transformer for the voltage you want, scale it down, in terms of power used / produced

[The Master]

I could use a PIC but im not sure why. Wouldnt that just turn things on/off to generate an AC output? That would result in a square wave too.

Thanks for the links. Ill have a read through them.

[Byte_Butcher]

A 6VAC motor? What frequency does it want?
Is it really AC only, or is it a "universal" motor that runs on AC or DC? Does it have brushes?

Building a converter to drive it should be easy enough, but I'd be curious to know more about the specifics of the motor first.


steve

[The Master]

Unfortunately i dont know much about the motor. I tried searching google for its number but i didnt find anything useful.

Heres what it says on the label:-
41TYZ-A synchronous motor
AC 6V 50/60Hz 1.5/2W
5r/min Cw/CCw

[Byte_Butcher]

Ahhh. It's a synchronous motor, so it not only wants AC, but it wants AC at 50/60 Hz and it probably wants at least a modest approximation of a sine wave. A square wave will probably make it unhappy...

Is efficiency a big issue? Gonna plug it into the wall, or run it off a battery?

If efficiency isn't really an issue, then a hardware solution with an op-amp based sinewave generator feeding an audio amplifier type driver is probably easiest.

steve

[The Master]

Im not too bothered about efficiency. It will be run from a mains transformer but the 12V DC needs to be turned on/off using a transistor and the motor will be connected with 64 LEDs (on the DC side). I can use a more powerfull transistor than normal but i dont want it to be using too much current.

Ill have a look for op-amp sinewave circuits. Ive not done much with op-amps before so this is the perfect learning opportunity

[Acetronics2]

An OPA triangle generator with clamping diodes on the output, plus a bridge audio amp ( TDA2005 i.e ) could produce an acceptable waveform ...

"Sine" generator is not so difficult to build nor ...

don't you think ???

Alain

[Byte_Butcher]

Op-amp sine generators are easy to build. A google search will get you lots of hits. Here's a couple of pages to start:

http://www.ti.com/sc/docs/apps/msp/journal/aug2000/aug_07.pdf
http://www.national.com/nationaledge/jun04/article.html

Drive a TDA2005 or similar like Alain suggested and you're done...


steve

[The Master]

That looks easy enough. Ill add the parts to my next order and see how it goes. Thanks :)