Problem For Motor Calculation !

Batik

What is a full load of a 3 phase,25HP,575V motor??
A 9A
B 21A
C 27A
D 31A

I used this formula but it couldt help me I=HP*746/1.73*V

And the second one
What is a power factor single phase, 2.1kVA load with a power factor of 90%.
a 1.9
b 1.91
c 1.911
d .19

it should be 0.9=KW/2100VA=> kW=0.9*2100=1890 => 1.9 but correect answer is 1.91.....why ???

KennMacMoragh

Using your formula for the top one, I got 18.75A. I used to be able to answer questions like the one you have on the bottom, but I've forgotten most of it. Power types are a pain, you need to study up on apparent power, reactive power, and real power. But like I said before, go to school, take an industrial motors class.

Batik

Kenn i know all staff and i did all calculations very good .... i dont have problem with electrical knowledges and math ,,,, this question only i could not be because i think something wrong ....so i share with u guys to know your opinion

piercekiltoff

1) 27 Amps (26.8 actually), based on HP = V * I * Eff / 746 => I = 25HP x 746 / 575V x 90% (eff) x 115% (power factor).

2)

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wareagle

I am not sure how your are supposed to get your answer but the code requires circuit ampacity to be determined from table 430.250. A 25 HP at 575 volts is 27 amps.
This is a poorly written question. If you are to determine what the kw load is when the PF is 0.90 the answer is 2.1 kva x 0.90 Pf = 1.89 kw. Your answer is correct. It is silly to try to determine a correct answer when
a, b, and c are virtually the same.

Bubbles

I'm telling you guys....Batik is a practical joker. He is an instigator. He's trying to ruffle some feathers if you catch my drift. 1.9, 1.91, etc....he is screwing with all of us. I think it's 480 or Zinsco or Speedy Petey in their altar ego form

rselectric1

Bubbles I agree that he might be a scammer, but I know your candidates (480 & speedy) are wrong. Zinsco is newer but why would he argue with himself? Also he seems to be a colorful but serious guy. I can't buy it.

I personally think it's Jimmy Wonton!

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Batik

Are u crazy bubbles ???? IT IS A FORUM AND ANYONE CAN ASK HIS QUESTION ....
AND THIS IS A QUESTION FROM EXAM TEST AND I WAS WONDERING WHEN I SAW , SO I DECIDED TO KNOW YOUR OPINION GUYS ...
BUT U ARE SPEAKING STUPID THINGS THAT I AM A JOKER HTC....DONT TELL PEOPLE WRONG THINGS IF U DONT KNOW WHAT TO SAY

Batik

piercekiltoff and wareagle , thank u guys U helped me ....

Bubbles

Then take a pic of yourself and tomorrows wall street times and post. Besides, i've never seen a test with those options other than 2nd grade when your working on your decimals.

Prove It!

Batik

Take pic yourself i dont have time for stupid things , and if u dont trust it does not mean that im a joker ....

Bubbles

Are you from indonesia? I had a few friends in the physics dept that talked like you. Joker is not necessarily a bad word. Did you come through Toronto? I used to live up there. I knew a guy named Batik off 134th st.

rselectric1

Batik, I think alot of us are willing to give you the benefit of the doubt here...BUT

Here's an idea: Fill out your profile...WTF is AAA?

I defended you in a previous post (I don't know if it was this one because you have started several) but with all your yelling and demanding, you will ABSOLUTELY get smack from the posters here.

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Bubbles

Watch out!

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Batik

i think guys u have too much free time just killing time in forum , i asked a question and it was really thriky question in exam and i asked , and there were people who understood my question very well and answered me and i was satisfy , but u guys i dont know what do u want from me ....u dont know me and u called me joker and spoke something different which is out of theme i asked ,,,,whatever i asked my question and i got really good answer thanks piercek and wariagle

Bubbles

Batik, chill out! What the heck are you doing up at 3 am for anyhow? Most electricians are in bed by 11 pm. Try some milk. It has tryptophan in it which might help you relax and sleep. If that doesnt work try some melatonin. It works great too, but then you have that sleepy paste on your eyelids in the morning. Ambien would be the next step but that's a harsh drug. Deep breathing works too. Were you up studying late last night?

Magnettica

What is a full load of a 3 phase,25HP,575V motor??

27 amps, table 430.250

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Brian Butz

27 amps. There is no calculation. Full load current is taken from Table 430.250

Leo G

Thread is almost two years old. I hope this guy passed already.

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