2PAC Mafia
Member
Hello,
Someone Electro: get an MOSFET that can suply more curnet.If its high enugh it will be just warm whithout an heatsink.
the IRF3205 can suply 110A at 55V and its in an TO-220(This is like most power transistors and voltage regulator) Over here you can get it for $2.
I have checked the price here and is around 8€, a little bit more expensive than in your country. Anyway if you think with this one would not be necessary heatsink sounds good...
Someone Electro: All you need then is an simple 555 timer to drive it
Why? With the tests with the IRFP350A I only drove it with 2 resistors to get the 10V at Vds.
Oznog: Still, off the shelf, I'd say this project can easily run 30-40euro or more, and the results will be less than "satisfactory" due to the size and heat generated. It will also run down your battery pretty fast! That's why I suggest getting a 12v vacuum which is quite common.
I take it you want a learning experience here. First thing to learn is nobody will ever design a linear regulator like this, it's impractical. When we have to step down voltages like this we use a DC/DC converter- a switching reg- which will do the job cleanly. Cool, efficient, and cheaper than huge FETs and heatsinks. It would be difficult for us to communicate how to do this to you because it doesn't sound like you're ready for advanced circuits like this.
At the moment I didn´t pay any euro in all my tests, I found this IRFP350A on an used board I had from a broken gym running machine and I worked on my job workbench where I have all the material for working, power supplies, soldering station, oscilloscope...
I also checked the prices for this 12V vacuum and I won´t buy one, not necessary. The battery I will use is the car´s one when the car is running at idle so it took the power from the alternator so no problems to discharge the battery.
I don´t care about people do themselves, I had an idea and I´m trying to find the best and cheap way to do it, if it´s finally not possible to do due to the price and it has no sense then no problem, at least I know I tried it and I learnt a lot of things. In my job I´m the only electronic technician and although my studies were for designing electronic circuits (1 year private school for general electronic knowledge + 2 years official school for electronic technician), I don´t have a lot of options to design. I try to learn new things every day because sometimes my job don´t give me that knowledge or I have to take it myself, I don´t have job mates to discuss here about pure electronic, all my mates are pure mechanic guys. I always then have to test or think myself only using my electronic knowledge or asking in forums as I´m doing to get new ideas...
I know there are a lot of more professional ways to do this project I asked for but it´s only like a hobby in this case exactly so I don´t want to use a SMPSU or DC/DC or whatever has no sense in this case.
I think I´m prepared to analyse circuits, design, repair... because I already did it, may be not so as you or not so as I would like, but why not?
Sebi: When You thinking about independent box, i think my idea a with car-bulb better. Try with 120W bulb (or two 60W parallel) Johnson motor is very strong and bullet-proof: my hand-drill specified for 12V 6A and i use this device about 20 years with self-built thyristor RPM controller from 24V. When the 3mm diameter drill go through a metal plate, the current over 20A! ...and work fine. I know, this is a barbarism, but i purchased two spare motors and no needed.
Thank you, if I can I will test also that option, but if I put this bulb in serial in theory the bulb will take the 12V and then I only will have 2,4V available at the motor, isn´t it? That wouldn´t be enough voltage at the Johnson motor where I have to put at least 3,7V.
Will B: I dont think that motor could possibly draw 7A ..
0.7 is more like it..
that motor is only about an inch in dia.!!
You are wrong, it runs 7A, and more if I put more voltage at its pins. This DC motors are very powerful, believe me!!!
Thanks for all your answers.
Someone Electro: get an MOSFET that can suply more curnet.If its high enugh it will be just warm whithout an heatsink.
the IRF3205 can suply 110A at 55V and its in an TO-220(This is like most power transistors and voltage regulator) Over here you can get it for $2.
I have checked the price here and is around 8€, a little bit more expensive than in your country. Anyway if you think with this one would not be necessary heatsink sounds good...
Someone Electro: All you need then is an simple 555 timer to drive it
Why? With the tests with the IRFP350A I only drove it with 2 resistors to get the 10V at Vds.
Oznog: Still, off the shelf, I'd say this project can easily run 30-40euro or more, and the results will be less than "satisfactory" due to the size and heat generated. It will also run down your battery pretty fast! That's why I suggest getting a 12v vacuum which is quite common.
I take it you want a learning experience here. First thing to learn is nobody will ever design a linear regulator like this, it's impractical. When we have to step down voltages like this we use a DC/DC converter- a switching reg- which will do the job cleanly. Cool, efficient, and cheaper than huge FETs and heatsinks. It would be difficult for us to communicate how to do this to you because it doesn't sound like you're ready for advanced circuits like this.
At the moment I didn´t pay any euro in all my tests, I found this IRFP350A on an used board I had from a broken gym running machine and I worked on my job workbench where I have all the material for working, power supplies, soldering station, oscilloscope...
I also checked the prices for this 12V vacuum and I won´t buy one, not necessary. The battery I will use is the car´s one when the car is running at idle so it took the power from the alternator so no problems to discharge the battery.
I don´t care about people do themselves, I had an idea and I´m trying to find the best and cheap way to do it, if it´s finally not possible to do due to the price and it has no sense then no problem, at least I know I tried it and I learnt a lot of things. In my job I´m the only electronic technician and although my studies were for designing electronic circuits (1 year private school for general electronic knowledge + 2 years official school for electronic technician), I don´t have a lot of options to design. I try to learn new things every day because sometimes my job don´t give me that knowledge or I have to take it myself, I don´t have job mates to discuss here about pure electronic, all my mates are pure mechanic guys. I always then have to test or think myself only using my electronic knowledge or asking in forums as I´m doing to get new ideas...
I know there are a lot of more professional ways to do this project I asked for but it´s only like a hobby in this case exactly so I don´t want to use a SMPSU or DC/DC or whatever has no sense in this case.
I think I´m prepared to analyse circuits, design, repair... because I already did it, may be not so as you or not so as I would like, but why not?
Sebi: When You thinking about independent box, i think my idea a with car-bulb better. Try with 120W bulb (or two 60W parallel) Johnson motor is very strong and bullet-proof: my hand-drill specified for 12V 6A and i use this device about 20 years with self-built thyristor RPM controller from 24V. When the 3mm diameter drill go through a metal plate, the current over 20A! ...and work fine. I know, this is a barbarism, but i purchased two spare motors and no needed.
Thank you, if I can I will test also that option, but if I put this bulb in serial in theory the bulb will take the 12V and then I only will have 2,4V available at the motor, isn´t it? That wouldn´t be enough voltage at the Johnson motor where I have to put at least 3,7V.
Will B: I dont think that motor could possibly draw 7A ..
0.7 is more like it..
that motor is only about an inch in dia.!!
You are wrong, it runs 7A, and more if I put more voltage at its pins. This DC motors are very powerful, believe me!!!
Thanks for all your answers.