Peak Demand - CR4 Discussion Thread

Home

Products & Services

Engineering News

Standards

Webinars

Engineering Forum

Login

CR4 Home | Electrical Engineering | Electrical Engineering

13 comments

Rate

Comments: Nested

Anonymous Poster #1	Peak Demand 03/05/2014 7:24 AM
	What would be the approximate peak demand for a 75 kW AC motor if it were 75% loaded, had a rated efficiency of 95%, and a power factor of 0.86? a 72 kW b. 59 kW c. 67.0 kW d. 79.0 kW
	Reply

Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Join CR4, The Engineer's Place for News and Discussion!

RAMConsult Guru Join Date: May 2007 Location: NYC metropolitan area. Posts: 3230 Good Answers: 444	#1 Re: Peak Demand 03/05/2014 8:24 AM
	What was your answer, please show the math, and clarify your doubts. We don't do homework here. __________________ “Tell me and I forget. Teach me and I remember. Involve me and I learn.” Ben Franklin.
	Reply

Fredski Guru Join Date: Feb 2011 Posts: 7025 Good Answers: 207	#2 Re: Peak Demand 03/05/2014 8:28 AM
	busy day for home questions damn anons
	Reply

lyn Guru Join Date: Oct 2008 Posts: 42355 Good Answers: 1693	#3 In reply to #2 Re: Peak Demand 03/05/2014 8:39 AM
	All the more reason to ban anonymous posters! But, then they just come back as ZAFRUL
	Reply

PWSlack Guru Join Date: Jan 2007 Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on. Posts: 32175 Good Answers: 839	#4 Re: Peak Demand 03/05/2014 8:54 AM
	Show the working for commentary upon it. __________________ "Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
	Reply

Codemaster Guru Join Date: Jul 2005 Location: Stoke-on-Trent, UK Posts: 4496 Good Answers: 137	#5 Re: Peak Demand 03/05/2014 1:33 PM
	Depends what you (or the homework setter) means by peak demand. If it includes start-up, I'd say none of the above. __________________ Give masochists a fair crack of the whip
	Reply

jack of all trades Guru Join Date: Sep 2006 Location: Auckland, New Zealand Posts: 8777 Good Answers: 376	#6 Re: Peak Demand 03/05/2014 1:43 PM
	Approximately all of them as (by definition) this is strictly true and hence a correct answer. Go on, pass that in as your answer to your tutor, I dare you. __________________ jack of all trades
	Reply

Codemaster Guru Join Date: Jul 2005 Location: Stoke-on-Trent, UK Posts: 4496 Good Answers: 137	#7 In reply to #6 Re: Peak Demand 03/05/2014 1:59 PM
	To misquote George Orwell, all are approximate, but some are more approximate than others. __________________ Give masochists a fair crack of the whip
	Reply Off Topic (Score 5)

lyn Guru Join Date: Oct 2008 Posts: 42355 Good Answers: 1693	#8 Re: Peak Demand 03/05/2014 2:21 PM
	The answer is d. The motor is defective and about to burn up. The overload was wired incorrectly.
	Reply

jack of all trades Guru Join Date: Sep 2006 Location: Auckland, New Zealand Posts: 8777 Good Answers: 376	#9 In reply to #8 Re: Peak Demand 03/05/2014 3:38 PM
	The supply voltage may also be too high. Damn real world Engineering is more complicated than it appears. __________________ jack of all trades
	Reply Off Topic (Score 5)

lyn Guru Join Date: Oct 2008 Posts: 42355 Good Answers: 1693	#10 In reply to #9 Re: Peak Demand 03/05/2014 3:51 PM
	So is the helpless AP#1"s homework, too.
	Reply Off Topic (Score 5)

JRaef Guru Join Date: Sep 2006 Location: California, USA, where the Godless live next door to God. Posts: 4665 Good Answers: 804	#11 Re: Peak Demand 03/05/2014 5:52 PM
	Fixed it for you... How can I get dome other fool to do my homework for me by telling me the approximate peak demand for a 75 kW AC motor if it were 75% loaded, had a rated efficiency of 95%, and a power factor of 0.86? Yet another management student... __________________ All I every really wanted to be, was... A LUMBERJACK!.
	Reply

Tornado Guru Join Date: May 2009 Location: Richland, WA, USA Posts: 21017 Good Answers: 795	#12 Re: Peak Demand 03/05/2014 11:58 PM
	Another improperly formulated question. There must be some weird instructors out there.... __________________ In vino veritas; in cervisia carmen; in aqua E. coli.
	Reply

Crabtree Guru Join Date: Jul 2007 Location: Commissariat de Police, Nouvions, occupied France, 1942. Posts: 2599 Good Answers: 77	#13 Re: Peak Demand 03/06/2014 9:59 AM
	75kW is the peak demand for this particular motor. Any more and the overload would operate, Boo-boo! __________________ Good moaning!
	Reply Score 2 for Off Topic

Copy to Clipboard

Users who posted comments:

Codemaster (2); Crabtree (1); Fredski (1); jack of all trades (2); JRaef (1); lyn (3); PWSlack (1); RAMConsult (1); Tornado (1)

	Got Something to Say?
	Ask a Question Start a Discussion

	Search this Forum
	Electrical Engineering: Go

CR4 Sections

	Aerospace
	BioMech & BioMed
	Chemical & Material Science
	Civil Engineering
	Communications & Electronics
	Education and Engineering Careers
	Electrical Engineering
	General Discussion
	Instrumentation
	Manufacturing
	Mechanical Engineering
	New Technologies & Research
	Software & Programming
	Sustainable Engineering
	Transportation

	Site Directories
	Forum Directory Blog Directory User Group Directory RSS Feeds CR4 Rules of Conduct CR4 FAQ Site Glossary Who's Online (103 right now) Show Members