There were a couple questions that I was hoping you could help me out with. I reviewed the material I have from Mike Holt and did some digging around online for similar questions and couldn't find anything. Any help would be appreciated.

Question 1:

-A 3-hp pump is installed 220 feet from the 220-volt main service. What is the voltage drop when using 12 AWG solid wire?

I have been reviewing the voltage drop calculation material and can't seem to find anything similar to this question. They don't give you the current which makes it confusing to me. I'm not sure which type of equation I should be using.

Question 2:

-A feeder supplies a continuous lighting load of 45 amperes and a single motor load of 30 amperes. What is the ampere rating of the feeder?

My answer: 86 amps

Correct Answer: 94 amps

I used code section 215.2(A)(1)(A) and am not quite sure what I missed.

215.2 Minimum Rating and Size.

(A) Feeders Not More Than 600 Volts.

(1) General. Feeder conductors shall have an ampacity not

less than required to supply the load as calculated in Parts

III, IV, and V of Article 220. Conductors shall be sized to

carry not less than the larger of 215.2(A)(l)(a) or (b).

(a) Where a feeder supplies continuous loads or any

combination of continuous and noncontinuous loads, the

minimum feeder conductor size shall have an allowable

ampacity not less than the noncontinuous load plus

125 percent of the continuous load.

Question 3:

-Approximately how many kilowatts are used by a three-phase, 480-volt ac motor that draws a current of 52 amperes and has a power factor rating of 88%?

I'm not sure what equation to use for this one either.

Thanks again,

Mike ]]>

What is the demand load for twenty single phase 14kw 208volt ranges on a three phase service?

Step 1: Determine the maximum number or ranges between any two phases: 7 units

How do you determine the 7 units? ]]>

It happens that I am preparing a preliminary project, for the installation of a factory of electrical equipment, power panels and control.

The question is the following, do you know any of you where I could do a course of manufacturing power panels and control?

I urge this information, thank you all!

I can write for whatsapp 1829 630 8682, from Dominican Republic:) ]]>

2014 nec cycle

A 120v/208v wye service has a computed load of 350 amps. the neutral is considered a current carrying conductor as 52 percent of the load is nonlinear. it will be installed in RMC. what is the smallest THHN copper conductor that may be used.

choices are 400, 500, 600, 750 Kcmil

soo, the answer states that its 4 conductors. that i understand.

so we adjust by adjust by 80%

they show 600 as the correct answer

then it states if over 100 amps that we use 75deg column per 110.14 (C)1(b)1 and shows how 600mcm is used based on 90deg table to get 380amps after adjustment.

but doesnt 110.14 mean we have to use 75deg column? so 750mcm is actually correct??

would really like some clarification if possible thank you.:?:? ]]>

Sent from my iPhone using Tapatalk ]]>

Well, I thought it would be bigger, but here goes. I understand fwd. biasing of the PN junction, and how the left figure's diode is fwd biased, and the right figure is too. What I have never quite grasped, is what is the reason on these two half-wave rectifiers--that the left one develops only the negative alternation across the load, while the right figure does the opposite? I realize that in both, the cathode is negative with respect to the anode (the definition of fwd. biasing), but WHY does one create just the negative portion of the sine wave while the other renders the positive half to the resistor?

If I could get this answered, my kingdom is yours. :) Not much in the way of jewels and binoculars, but boy do I feel like an ass.

Help?

Thank you.

Larry.