A few questions

[iwire]

Re: A few questions

Originally posted by rattus:
Apparent power should have been computed for both motors.

We don't know the PF or the efficiency of either motor, so we can't really apply those factors here.

Geeezzz, your making a mountain out of a mole hill, but I suppose that is what we do here.

If you go back to my original post I stated;

Some short answers, others will surly elaborate.

My 10 HP motors have no PF, the motors are not real. I pulled the info out of the motor tables in 430.

I was just trying to show the advantage of using three phase, I thought I put enough 'abouts' and vagueness in my post that all would see it for what it was....just a rough example.

I mean really, how deep should I go when the OP is asking about why a neutral is not needed at a 3 phase motor? :roll:

 

[rattus]

Re: A few questions

iwire,

Just making the point that your example as written could be interpreted wrongly, especially by those unschooled in 3-phase stuff.

I have been schooled in 3-phase, but have never worked with it, and that must show. Still, it is fun to kick around the numbers when one is too old to do anything else.

Now it is likely that the 3-phase motor is more efficient which would make the difference more dramatic.

This would be an interesting experiment to compare the efficiencies and PFs of the two motors delivering the same power.

 

[roger]

Re: A few questions

Rattus,

Still, it is fun to kick around the numbers when one is too old to do anything else.

to old to do anything else? Your experience and knowledge is an instructional tool to say the least, so don't think you are simply posting blanks.

Us younger guys may still challenge you though.

Roger

 

[rattus]

Re: A few questions

Roger, you flatter me; keep it up! In engine school we had to take power courses which I rather enjoyed even though I knew I would work in electronics. I do not regret it.

I enjoy these exchanges as long as they are honest and civil. And, maybe someone might learn something. I have.

When in doubt, I refer to the smartest man I know who was kicked out of school in his Freshman year because he would not attend lectures. He only came in to ace the quizzes!
Lucky for him, a few people noticed his superior intellect and managed to get him employed where he could flourish.

 

[rattus]

Re: A few questions

cpal,

The Signal Corps motto has been reworded a bit, but you get my drift.

 

[iwire]

Re: A few questions

Originally posted by rattus:
iwire,

Just making the point that your example as written could be interpreted wrongly, especially by those unschooled in 3-phase stuff.

I have been schooled in 3-phase, but have never worked with it, and that must show. Still, it is fun to kick around the numbers when one is too old to do anything else.

Well you are correct it could be misinterpreted.

I see the high caliber of your posts that go so far over my head that I can not even see them. I just assumed you had worked with three phase equipment, my mistake not yours.

I second Roger's post that your knowledge is a great benefit to the members here.

To old? no, just very experienced.

Bob

 

[rattus]

Re: A few questions

iwire, thank you for your praise; keep it up. Although my resume' says 40 plus years experience, it was more like one year 40 times! No, that is not right either; it is somewhere in between.

I tend to stress the fundamentals because if you get those wrong, you will never know what you are doing.

Rattus