Dude99 - Engineer Boards
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# Dude99

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## Previous Fields

• Engineering Field
EE

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1. ## Watts Per Square Foot by Building Type

Or ASHRAE https://elearning.ashrae.org/design-for-building-electrical-systems.html
2. ## Voltage Drop Calculations

Wrong...again that is not a trick, that is seeing if you can separate the wheat from the chaff. Most real world problems require gather all information and eliminating the 'noise'. Obviously it is important to know what the 'question is asking'. lol The 'best' approach varies by individual and is not the exclusive domain of one.
3. ## COVID-19

I don't understand why they are automatically refunding rather than asking if you want one or rescheduled for Oct.
4. ## Oh oh

Email Due to increased concerns related to the coronavirus disease 2019 (COVID-19), NCEES is canceling the April 2020 exam administration. This decision is based on the recommendations of public health officials to help contain and slow the spread of the virus and to help ensure the health and safety of our examinees and employees.
5. ## Cram for the PE Sample Test 1 - Problem #13

This is a good example: THINK before grabbing the pencil and calculator. can't be 0 unless it is the faulted line or inf bus no and no Z. can't be 13800 unless NO Z except a hi NGR. same for 12090, nrg must be >>>> X1 that leaves 6990, which makes sense since L-N is ~7970 imo the point of a question like this is to make you think about basics and give exercise on SC's, but I personally spend time on it during testing. No if the range of answers was: 6900, 6990, 7100, 7600, maybe. It can be done quickly using only Z and arrive at 6900. Don't always jump into the most complicated method, think basic concepts first.
6. ## Voltage Drop Calculations

You also thought 0.046 was 4 awg cmil. It's easy if they give you LOAD pf. But you don't need to go that far.
7. ## Voltage Drop Calculations

More than 1 way to skin a cat. In my opinion the test is looking for minimum competency, comprehension/understanding of concepts, not memorization or math skills. They are not trying to 'trick' anyone.
8. ## Voltage Drop Calculations

Who's to say?I've passed PE EE (general, decades ago) EE power and PE controls both within the last 10 yrs, and am taking the PE ME HVAC. any of the methods will get you there adjusted for pf
9. ## Voltage Drop Calculations

imo if they give conduit type and reference the NEC use their approximation method if they give Z in complex form use it isn't system pf = cos(line ang - load ang)?

11. ## Voltage Drop Calculations

The real part of 1.13/-24.4 = 1.03 exactly 1.0291, same as the NEC 1.0291
12. ## Voltage Drop Calculations

The way I do it X = 0.024, R = 0.155, Z Line phase = 8.8 deg, old pf = 0.85 31.79 deg, new 0.9 25.84 deg Z at 0.85 = 0.145 from table at 0.85 pf Z at 0.9 = Z x cos(Z line - Z load old/(cosZ line - Z load new) plugging Z = 0.1506 any method will get you 'close enough) if a motor load ph ang = acos(motor pf)
13. ## Voltage Drop Calculations

imho the NEC note is confusing they give you R and X hence the line ph ang = atan x/r assume 500' #4 R = 0.155 and X = 0.024 Z = R x cos(atan x/r) + j X sin(atan /r) = 0.153/8.8 deg using the NEC method of 0.9 x R + X x sin(acos 0.9) = 0.150 moot on 100 A load: 15.3 vs 15.0 drop
14. ## Voltage Drop Calculations

Z = 0.9 x 0.155 x sin(acos0.9) x 0.024 = 0.150 0.150 x 20 = 3 V 4 awg ~42,000 cmil