How can a Motor Nameplate say 5.6 AMP @460 VAC and also 5 HP?

[rix]

Are motor companies using a new math to calculate HP?

 

[TheStarr]

That is strange!

5.6A x 460V = 2576W/5 = 515
1HP = 745W
So, 2576/745W = 3.47HP

What brand/model?

 

[rix]

Baldor, They said it was an EFFICIENT motor!

 

[Bobbias]

It can't possibly be 144% efficient, lol.

 

[TheStarr]

Maybe you could hook it to a generator with a 5HP load? That 1149W difference could provide FREE POWER!!!!!

Good-bye Global Warming!

 

[Goody]

Maybe my engineer from my other post is reading the nameplate to you

 

[rix]

S.F is 1.15

(Maybe it has the new superconductor wire and air bearings?)

 

[bernie_carlton]

Post a picture

 

[L D[AR2P#0.0]]

Root 3 and the power factor is missing from your calculation.

 

[Mickey]

Root 3 and the power factor is missing from your calculation.

Yup and efficiency.

 

[rix]

Yup! that's it! pf=.93 and eff is 89.5% then root3 will come out 4.9 HP.
Thanks...

 

[DickDV]

As a really loose rule to estimate FLA on 3 phase 460V motors, you can figure 1.2 amps per hp. On small motors, say, under 5hp, it's usually higher than that and, on larger motors, say, over 150hp, it's usually less than that.

So, your motor still is a bit low in amps. This is (and I'm not being sarcastic here) due to efficiencies getting better and better. Premium efficiency motors often run around 1.1amp per hp which is right where your motor is. And, the power factor is drifting lower too.

Unfortunately, the price to pay for that is higher inrush current when starting a stopped motor. Where 5 to 6 times FLA was the norm for inrush, some of these premium efficient motors (especially NEMA Type A) have inrushes over 14 times FLA.

That's not a problem when the motor is on an inverter but, across the line, the lights blink for good reason when the start button is pushed.

 

[milldrone]

due to efficiencies getting better and better.

That's not a problem when the motor is on an inverter but, across the line, the lights blink for good reason when the start button is pushed

Dick,

I hear that only premium efficient motors can be manufactured for sale after December 2010 in the states. This may mean that a new premium efficient motor may not fit where a regular motor was. Length may be an issue as well as the lights blinking on startup across the line.

Have you heard the same?

 

[DickDV]

I have not heard that, Milldrone. It may well be true but I doubt that the frame size of a particular motor will change. NEMA regulates that.

Higher efficiency is a good thing but, when politicians are doing the engineering, you can expect some surprises, most of them undesireable!

 

[milldrone]

I doubt that the frame size of a particular motor will change. NEMA regulates that.

I believe that the NEMA regs you are referring to regulate the maximum size of the motor envelope. A motor manufacturer can shorten the length from the bolt holes to the length of the fan housing if he wants, but he cannot exceed the regulation length. It's my understanding that the engineering of premium efficient motors begs for longer, smaller diameter rotors. Thus most motor manufactures will be using all of the length available to them. Some manufacturers do not always use all the length with product.

Higher efficiency is a good thing but, when politicians are doing the engineering, you can expect some surprises, most of them undesireable!

Yes, I believe this will give the foreign knock off artists an even bigger financial advantage. Presuming that they continue to make motors that "indicate that they meet the new regs" but in reality they do not!