Alternate Turbo. What kind of force do turbos make?

[JdrifterCA]

Hello, I'm thinking of making a force induction engine with a 1/5 hp. eletric motor. I want to know how much force a turbo's spining is making to see if 1/5 hp is enough to match up to 20lbs of air pressure.

[Amays U G37S]

ur 1/5 hp motor will not put 5 to the wheels

GOOD DAY SIR!

[gijoe392003]

Sorry to bring up an old thread, but I got some racing electric motors I used in RC racing. I heard turbos spin up to 50,000 rpm and these motors I have go between 20,000 and 30,000. I am never gonna do this, but I wonder if I fabricated a compressor wheel and housing to one of these electric motors if there would be enough presser to actually do something.

By the way, this is just an idea and not in anyway something I would ever do unless I knew it was feasible.

[wingnut510]

^^ You can't be serious... Those little motors would never come close to the watts you will need to develope for a turbo app..

[gijoe392003]

Why not? Look at the headlamp motors. They run off the same battery as everything else, obviously not as powerful but the same principal applies. Although, these motors can't be run for long lengths of time (five to six minutes), but using in application like Drag might be useful. True, a normal turbo may be more efficient so this theory may not be very feasible, but this application can be used like a supercharger with out any of the dray backs. Wattage isn't what is at stack with these motors, it is amperage. Too much can fry these things in a heart beat. Plus, because there aren't as many amps being drawn, the alternator won't be worked any more than a head light.

Did some more research, as I haven't mess with these things in a long time, and found that the brush less motors can reach in excess of 60,000 RPMs for hours with deterioration.

[wingnut510]

Why not? Look at the headlamp motors. They run off the same battery as everything else, obviously not as powerful but the same principal applies.

Wattage isn't what is at stack with these motors, it is amperage.

Clearly, someone does not understand basic electromagnetism. Watts are a measure of work done, when expressed electrically [W = V x A {W=Watt, V=Volt, A= Ampere}] The Watts that the headlight motor generate through a reduction gearbox are probably around 100W. The little motor can only do the job because the reduction gear box helps to multiply the torque of the tiny motor.

Did some more research, as I haven't mess with these things in a long time, and found that the brush less motors can reach in excess of 60,000 RPMs for hours with deterioration.

Simply spinning a motor under no load is easy, and some can reach 60,000 RPM, but the motors described at the beginning of this thread (RC Cars) are not in that league. Regardless of the motor, the Watts need to spin an impeller fast enough would be in the neighborhood of 10-12 Kilowatts, conservatively. There are lots of variables involved, but lets just say that this is not in the league of the RC car motors.

[gijoe392003]

I know what wattage is, but of course I knew this seemed a little out of reach. Just an Idea. Thanks for the input.

[keelay]

Wow. Please don't take this harshly, but:

You completely fail to understand the basics of electricity, the basics of motors, how pressure affects how a motor powering an air pump, and lots of other intricacies.
Also, this complete failure has no business being in the engineering forum.

[gijoe392003]

Oh course I fail to understand. I am not even close to being an engineer. I have yet to learn everything I need to know about these things. Why do think I asked about it? Its funny how people take a question such as this seriously as it was theoretical. How am I supposed learn if all I get are 'YOU FAIL' replies such as yours. Thanks for not helping me, greatly appreciate it.

[ARKQX33V6]

Hold your horses GIJoe, your question is valid, as this is supposedly a forum of questions. Simply put to produce enough air pressure as used in Turbo or even super chargers the pressure goes to about 1+ atmosphere higher than normal atmosphere, so your going to need 15 PSIG above atmosphere.

That is not the problem because pressure alone can be created by that small motor but pressure is not work, along with pressure comes volume. Volume of air flowing through a carb or fuelly could be around 1000 cubic feet per minute.

Producing pressure is easy, slap your hands together and you make pressure, but it takes a combination of volume of air moving because of pressure or lack of it. Together pressure and volume of air makes work. In electrical things it take pressure, volts and amperage or the flow of electrons.

Volts by themselves do not do much work and work always takes time. Put volts with amps with time and then in combination you have the material to do work.

Volts and amps together are called either volt amps or watts. The name changes as to AC or DC energy, DC being watts. There are times when the AC energy is called watts but people have a tendency to call volts x amps watts. The name watts are used as DC energy because magnetic energy is not considered but in AC the magnetic energy causes a lot of differences in energy, in fact AC energy has 3 types of energy but only 1 type in DC.

So from your example of a headlight motor that was discussed as 100 W, which is a good size as far as watts goes that 100 W motor would draw 100/12 or 8.3 A, because in DC watts = V x A.

Also I need you to know that 746 W = 1 HP electrically and for that motor to be a 1 HP motor it would be about 7.46 x more energy.

To use an electric motor on an internal combustion engine to push 15 PSI of air at 1000 cubic feet per minute is going to take a large electric motor too large to power up atop an engine that drives along at 150 mph.

If you look at air compressors a 100 HP rotary screw compressor delivers about 400 CFM of air at 125 PSIG. Rotary screw type positive displacement machines are good at delivering pressure and volume but they require a large power for the prime mover. The smaller the compressed air needs as to pressure and volume the lower the HP needs. But the motor HP is in relation to CFM of air volume required.

Your small motor hooked to a tiny car engine may work on a miniature test track, but as an alternate turbo for a man sized car it is a bit small.

A lot of power is needed for Turbos and blowers but turbos use the waste energy from a positive displacement engine to make greater HP through pressure and volume. Although these devices have a bit of delay when their action is needed.

Both Turbo and blowers need power, there is still no free ride. your question is valid and it will take a lot of discussion to truly clarify the answer. 1/5 HP is not enough and high RPM is used to convert low pressure and low volume to higher pressure, all the same a very interesting question.

[gijoe392003]

Thanks you for that explanation. Its been a while since I have taken electronics class in HS, so this still seems foreign to me. Like I said in my first post, I don't intend to try this but I just wanted to see if it was possible.

ARKQX33V6 - From what your saying, a larger motor and much more power is needed to create the same pressure fro auto applications. I know thats what Wingnut was saying before.

Thanks again for all your input. Good thing I don't do this for a living.

[raremotive]

I would guess the power required to turn the turbo shaft would be roughly 7-10% of peak power at peak power.

so 21 to 30 HP turbine shaft power for 300 HP...

The true way is through thermodynamics. You would need to figure out from an open system calculation of how much energy it took to compress the air as well as heat the air since the compressor is only so efficient.

[Hardrvin]

Old topic, but thought I'd chime in. Take a peek at air injection pumps and the fuse they're on. It's a pathetic little turbo style fan that will likely be on a 50+ amp fuse and it hardly moves any air. Should give you a pretty good idea.

Though I've heard rumor that GM or Ford is dabbling w/ the idea of adding a small electric based turbo for some extra grunt.