Phase shift Oscillator

[yasir_ali]

there Must be some way to design this class D amplifier.

 

[yasir_ali]

Hey Hero! what i want is that, what i've designed the Oscillator, i should use it in the Circuit.
i'm including the schematic. but a 741 Ic can provide Max: 20mA but as you know the motor require 2.4A. so tell me that how can get more output Current? what i think is to simply replace the 741 Ic with an OPAmp that can provide 3A or More at the output. i think it is possible. what do you think? if YES then tell me how?
Thanks

 

[audioguru]

You must amplify the current of the opamp sine-wave generator plus you must amplify its voltage.
A linear (class-B or class-AB) audio amplifier would make a lot of heat so a class-D switching amplifier can be used.
But I have never seen a class-D audio amplifier with an output voltage as high as you need so it must drive a stepup transformer that increases the output current of the amplifier.

 

[yasir_ali]

Yes, Audioguru. i'm talking the same to use a step-up transformer instead of using a class D Amplifier.

 

[Hero999]

Have you looked to see if you can buy a controller for the motor?

Where did you get the motor from?

Unless it's specialist you should be able to buy a motor controller which will enable you to power it from 110V or 230V mains.

 

[yasir_ali]

Yes we can find the controller But it's my intention to drive this motor using my circuit.

 

[audioguru]

Yes, Audioguru. i'm talking the same to use a step-up transformer instead of using a class D Amplifier.

You must use a power amplifier to boost the current enough. The current into the low voltage primary of the transformer will be much higher tham the motor's current.
A linear power amplifier will produce almost 400W of heat. A class-D power amplifier will produce only 60W of heat.

 

[yasir_ali]

Now this is the problem that We can use class B amplifier because losses energy in heat form and Somehow Can't use class D Amplifier because it is Damn! Hard to design. we'll find a way in between them.

 

[audioguru]

Texas Instruments and other semiconductor manufacturers have class-D power amplifier ICs. The datasheet tells you exactly how to make the amplifier.

 

[yasir_ali]

Hey Guys One Rediculous Question araises in my mind is. after my Oscillator Stage which is providing 20mA. Can i use a power Amlifier? will this Amplifier increase POwer when the max: output of 741 is 20mA?
and help me in my circuit.
Thanks

 

[yasir_ali]

Hey audioguru! that's Fantastic. i'm searching for these Ics.

 

[Hero999]

What about using a simpler modified sinewave inverter?

The waveform can be filtered to make it more like a sinewave, if it's a problem for the motor.

The good thing about using 300Hz is the transformer can be on sixth of the size of a 50Hz mains transformer.

Using a modified sine wave inverter will make the project more feasible.

 

[yasir_ali]

you mean that we should modify the 50Hz from to the 300Hz?

 

[Hero999]

No, Google modified sine wave inverter and you'll se what I mean.