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 Topic Title: What is the formula? Topic Summary: Created On: 20 April 2013 03:37 PM Status: Read Only Linear : Threading : Single : Branch
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 20 April 2013 03:37 PM harper1993 Posts: 3 Joined: 02 April 2013 Can someone please help me out and give me the formula for this question, I have my C&G level 3 301 exam coming up in 3 weeks and im undertaking 5 hours revision a day. I did this kind of question at the start of the year but I have forgot the formula and cant find it anywhere.. A single phase circuit dissipates 2.5 kW of power and operates at a power factor of 0.95. The current flowing will be : A. 11.4A B. 10.32A C. 10.8A D.10.4A 21 April 2013 01:40 PM benmc Posts: 26 Joined: 02 November 2012 I = P/V I=2500/230 I= 10.86 i dont think you need to worry about the powerfactor too much as its 0.95 but i may be wrong, 21 April 2013 02:23 PM westonpa Posts: 1771 Joined: 10 October 2007 At which voltage? 21 April 2013 05:58 PM dazzjones Posts: 16 Joined: 12 July 2009 Hi harper, Assuming that the single phase voltage is 230V.... I = P / (V × cos φ) Power factor PF = cos φ Therefore... I = 2500w / (230 x 0.95) I = 2500 / 218.5 I = 11.44A Correct answer = A Hope this helps, Kind regards, Darren 02 June 2013 11:15 PM l30f1tz Posts: 2 Joined: 02 June 2013 Originally posted by: dazzjones Hi harper, Assuming that the single phase voltage is 230V.... I = P / (V × cos φ) Power factor PF = cos φ Therefore... I = 2500w / (230 x 0.95) I = 2500 / 218.5 I = 11.44A Correct answer = A Hope this helps, Kind regards, Darren +1 What Darren has said. If the voltage was not given and it stated single phase, then one can only assume its a 230V supply.
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