Question about E-motors

[Christ]

Originally Posted by ASV

use the 5H to buld up a little tork in a flywheel and use a clutch

How exactly do you think torque and horsepower work?

If I'm thinking on the same apparent wavelength that you are, you're suggesting that I use a clutch to get the car moving, slipping it in and out until I get up to speed... thus converting electrical energy to a bunch of heat and ceramic dust. I don't like that idea at all, especially when electric motors (usually) make max torque 'out of the hole', at the second they start moving.

[ASV]

well if you want you can just let that tittle motor try to get the car up to speed
but your going to move like a cargoship and the motor is going to make even more heat than a clutch would.

in fact you may want to add an extra mufinfan or somthing to ceep things cool
till you get some RPM to cool with

[Christ]

What are you basing your opinion on?

[ASV]

on fact


normal top speed for an AC motor that big is 3200 and is set up to work at near that speed
a compressor is at operating rpm in about a sec after startup

the 100% duty rating it has in a compressor is for that lode and that rpm it is not the one it will have in even a very small car
In a car its going to have a lot more work to do
Lets give you a nice small weight of 150 lb
batteries of a another 150 lbs
and very light 1200 lbs for the car

The motor can be free
All the drive components that must be spun up and moved forwards at the same time
can be free to
I won’t count that weight

That’s still 1500 lb or 3/4 ton

The compressors moving parts ?
Two pistons
One crank
the air and oil
one large fan pulley and one small non fan pulley
Two V belts or one B belt
The armature

Max maybe 30 lbs


what was yours based on?

[Christ]

So you're basically saying that since it's a compressor motor, it can't be run at a variable speed?

Keep in mind, that I (once again) would be using it in a vehicle whose total weight is less than or at 1,000 lbs, not counting myself. Wherever you're coming up with your weight figures, it's obviously not from reading my posts.

The 100% duty cycle of the motor means that it can be run at max output 100% of the time, not that it can't be run at variable speed. What do you think a VSC does? The motors in that link aren't just compressor motors, either.

...Applications: Conveyors-Air Compressors-Table Saws-Auger Feeders-Fans-Barn Cleaners-Silo Unloaders-Dairy & Poultry Equipment...

Table saws, conveyors, augers, fans, and many pieces of D&P equip run at variable speeds, using a VSC. Sure, none of those things just give the motor open contact and expect it to accelerate under load, but aside from overheating (which can be taken care of), what problem would it really be?

I do, however, know that I can't actually use those motors that I had linked. They're inductive motors, and I won't be able to get enough starting torque to move them without a complex, inefficient circuit.

Regardless of that point, the original question was whether a 5HP motor would be sufficient to move a small (</= 1000#) vehicle at city speeds, at or near 25MPH, on flat roads. That question has been answered. The answer is Yes.

[ASV]

no I am not saying that since it's a compressor motor, it can't be run at a variable speed


I am saying that it is going to take you a very long time to get up to speed and that you will need to cool the motor

you know

I was going to take that last post of yours apart but
I don’t see the point in arguing with some one who wants to fight instead and puts words in my mouth

[Christ]

Originally Posted by ASV

no I am not saying that since it's a compressor motor, it can't be run at a variable speed


I am saying that it is going to take you a very long time to get up to speed and that you will need to cool the motor

you know

I was going to take that last post of yours apart but
I don’t see the point in arguing with some one who wants to fight instead and puts words in my mouth

I've already figured out what I needed to know.

Thanks.

/thread.

Have a nice day.