Next Week

Sup!

 

How goes the battle out there? It has been a fast start to the new year here.  We have the pleasure of our Third Year Class in this week.  They are studying semiconductors, First Aid, and Electrical Safety Related Work Practices.  The class is doing well asking great questions.  They even asked how you are all doing. 

 

Your Second week of school is just about here….Just think, including next week you only have 21 weeks of class left.  Time goes by really fast.  Make sure to get the most out of each and every week. Still yet, make sure to learn as much as you can from your journeymen in the field.  They will provide much of the knowledge it takes to be a success in this trade.  Don't hesitate to ask them what it means to be a Union member.  You have found not only a job, not only a career, but a way of life.

 

There are 5 points still available for this week's homework login.  One point for answering the question, and four points for writing one…..remember the due date for logging in and receiving credit is on Friday.

 

See you all Monday.  Wear substantial attire for lab.  We will be spending time in the bending lab next week where there are trip hazards, drop hazards, and it is flippin cold out there.

 

Greg Greiner

LU112 NECA JATC

Instructor

greg.g@jatc112.org

 

Woot Woot!!! RLC Circuits Coming ThRouGh!!

Hey 2^nd  Year,

 

I hope you are all staying warm out there.  Everyone seems to have varying opinions, but I personally would always choose to be too hot as opposed to too cold.  It was all about layers. 

 

I am writing to say hi and see if everyone is doing okay on homework.  As for me, I am doing ok on mine.  Capacitance jumped me a little but I have since beat it back a bit.  Just remember it adds the opposite of Resistance. Also, watch out for what has positive angles versus negative ones in regards to Reactances.  In series, inductive reactance is 90 degrees positive and capacitive reactance is 90 degrees negative. (They are 180 from each other.)  In parallel, the inductive reactance is 90 degrees negative and the capacitive reactance is 90 degrees positive.  Values calculated for resistors are always in phase at zero degrees. 

 

One of the real keys to understanding AC theory is understanding how to find Z.  In series, impedance triangles are your bestest friend.  In parallel however, one cannot…NOT….not…N O T. (I have tried it ..ugh)..not make impedance triangles.  Therefore, in order to find Z in a parallel branch, one must calculate the current through each component and make Current Triangles.  The current through a resistor is at 0 degrees, the current through a capacitor is at 90 degrees, and the current through an inductor is at -90 degrees.   Once you find the Current total (using Pythagorean), good old Georg Ohm comes in to play.  Z equals the voltage divided by the current.

 

As I said, the key is knowing how to compute Z.  In series use impedance triangles. In parallel use current triangles.

 

 

Hope that helps.  If not, I am very sorry….and no, you cannot get back those 2 minutes of your life.  maniacal laugh!!! 

 

 

Greg Greiner

LU112 NECA JATC

Instructor

greg.g@jatc112.org

 

Howdy first year apprentices-

Only three assignments left and the class average is only 66% complete.  Of course two people with 0% turned in skews the numbers a bit but I was hoping for better results since it was the group that asked for points to be assigned.

On a brighter note there have been great questions posted.  Here are a couple.

Q:This may seem like a silly question and I have laid almost 2 miles of ground cable but what exactly does a ground cable do in the event of electrical shock?
A: Check the NEC, ART 250, Section 250.2-Definitions.  Piecing together a couple of thoughts there, grounding systems-stabilizes the voltage to ground during normal operation and facilitates the operation of overcurrent protection.  Grounding equipment limits the voltage to ground on these materials.  In other words, if you are touching a piece of electrical equipment and a fault happens; you, the equipment and the ground you are standing on will be close enough to the same potential as to avoid shock.  Keeping all equipment, the building, and other systems like plumbing bonded together avoids arcing and sparking during events like lightning strikes, thus avoiding fires as well as shock.

Q:When it says due date, Nov 25 how do we submit homework?
A:You aren't submitting homework, you are answering specific questions.  The questions are not too difficult.  For example "I have met my goals for 9 DEC" just means yes, or no, did you do the homework you wanted to accomplish that week.  Use the form, email, fax, leave a phone message, leave a note in our mailbox, whatever you want to do BEFORE THE DEADLINE to answer that simple question.


Greg McMurphy
Instructor
LU112-NECA Electrical Training Center
Kennewick, WA 99336