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Susan Brown

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Viewing 15 posts - 1,231 through 1,245 (of 1,948 total)
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  • in reply to: Mod 7 Unit 1 Quiz #18895
    Susan Brown
    Keymaster

      Hi Joe,

      Here’s the paragraph from Mod 7, unit 1:

      It’s also not uncommon to see switches test fine with your ohm meter but then not work right when they’re in a live circuit actually switching voltage. This is called “failing under load.” That’s why I personally prefer doing my troubleshooting on a live circuit and testing for voltages rather than checking for continuity. Continuity tests are okay, sometimes necessary, sometimes expedient. But the gold standard for testing components like switches is live voltage testing.

      Here are the 3 answer choices for the quiz:

      It’s not actuating properly.
      It checks good on continuity but fails in a live circuit.
      It’s having trouble carrying its weight.

      in reply to: Oscilloscope for Troubleshooting #18890
      Susan Brown
      Keymaster

        Hi Steve,

        Good question! Appliance techs don’t need an Oscilloscope for their work in the field. The one you see in the video is primarily used for training/teaching purposes, rather than diagnostics.

        in reply to: series and parallel circuits #18885
        Susan Brown
        Keymaster

          Hi Rudy,

          Thanks for your comments.

          We’ve had about 2000 students go through the course over the past few years, but are always open to student feedback. I’ll take a look at the items you’ve mentioned.

          But I also wanted to point out that we have these Ask the Teacher Forums to account for the fact that everyone has different needs when it comes to training and learning. You do have two attempts available on each quiz, as you know, and we also have the reset program. So, if after taking a quiz for the first time there are questions that aren’t clear to you, just ask us to clarify!

          Susan Brown
          Keymaster

            Good question, Matt.

            There are two resistances in the circuit – the loose connection and the element.

            To get the heat generated by one of the resistances only, the “E” in the equation P=IxE would have to the be voltage drop across that individual load, not the total voltage.

            So, you’d have to calculate voltage drop across the loose connection.

            This is do-able, but most students have an easier time of following the logic behind the technique shown above in V’s post and in the video. And it requires fewer steps.

            Here’s how you could do it.

            The total voltage dropped across the entire circuit is 240vac.

            The resistances (in our video scenario) are 32 ohms and 5 ohms, so total is 37ohms

            Voltage drop across loose connection is directly proportional to the resistance of that connection, so is
            240 (5/37) = 32.4 volts

            32.4 x 6.5 = 211 watts

            so – that’s a little more complicated than just using P = I squared x R

            Susan Brown
            Keymaster

              Yes – that is correct – good job!

              FYI – I’ll need to hide part of your answer so we don’t give it away to other students.

              in reply to: Rounding Numbers Using Ohm’s Law #18865
              Susan Brown
              Keymaster

                Good question!

                You’ll get a feel for these numbers as you go along. Here are a few guidelines.

                Ohms and Watts do not need to be reported with any decimal places – whole numbers are fine.

                With the example you gave, of 1350 watts vs. 1352 watts, those are essentially the same. When you’re talking about overall values in the hundreds or thousands, a few watts one way or the other in the “ones” place doesn’t matter.

                Amps is where you usually will see smaller, more precise numbers, like 3.2 or 6.5.

                Hope that helps!

                in reply to: Module 8/Unit 2 #18861
                Susan Brown
                Keymaster

                  You’re welcome! So far so good.

                  in reply to: Dan Foss App #18856
                  Susan Brown
                  Keymaster

                    Hi Don,

                    It looks like Danfoss made some updates to their data to be more accurate. The pressure values they give now are about 0.2 psi lower than they were when we made that video. It’s a small difference — and wouldn’t really be consequential in troubleshooting.

                    in reply to: Module 8/Unit 2 #18855
                    Susan Brown
                    Keymaster

                      Hi Darren,

                      The Midterm is a uniquely challenging exam in the course – that’s why we created that study sheet.

                      The Final exam is largely based on the unit quiz questions that you encountered throughout the course. The biggest difference is when you get to the Open Answer exam and have to write definitions and do a few calculations on your own. The final exam has a higher first-attempt passing rate than the Midterm, FYI.

                      So the best way to study is to review each unit and quiz, to refresh your memory. If you’ve been keeping a notebook, that will help a lot.

                      Keep a calculator, pen, and paper handy.

                      in reply to: 1.9: Core- Operational Overview Top-Load Washer Unit 5 #18849
                      Susan Brown
                      Keymaster

                        You found a typo – thank you! It’s supposed to be “drain pipe”.

                        in reply to: midterm question 7 ,8,9 #18846
                        Susan Brown
                        Keymaster

                          Hi Christopher,

                          We have two circuits that are in parallel
                          1. convection element
                          2. convection fan motor

                          In our scenario, they are functioning normally and then, boom! A component (the diode) in the element branch fails open.

                          (Note: The fact that it is a diode is unimportant for this particular scenario. The point is just that a component in that circuit fails open.)

                          The fan is not in the same circuit as the diode.

                          Image a big red “x” over the convection element – that circuit has just stopped functioning because the diode failed open.

                          Now do the “zen trick” on the convection fan. Can you still reach L1 and N?

                          (By the way, the videos at the end of Unit 4 are very helpful for this question.)

                          in reply to: Mod 5 Unit 5 Quiz #18844
                          Susan Brown
                          Keymaster

                            Yep! Good 🙂

                            in reply to: Mod 5 Unit 5 Quiz #18842
                            Susan Brown
                            Keymaster

                              You are correct – that reference sheet doesn’t have a triac symbol. That’s why we show it in a later unit when we discuss them. Maybe you can draw it on your printout!

                              drain pump triac

                              in reply to: Mod 5 Unit 5 Quiz #18839
                              Susan Brown
                              Keymaster

                                5 and 21 are correct.

                                Question #3 – You arrive on a service call for a washer that’s DOA — no lights, no beeps, no nuttin’. You’ve already verified a valid power supply at the outlet and that the washer is plugged in. Your troubleshooting strategy at this point is to

                                The answer is just kind of the logical way to proceed. Your outlet is fine, but the whole unit is “dead”. You would just follow the line (power) cord up into the machine, measuring voltage until you find where you’re losing it.

                                Question 10
                                From the Electronics module, unit 3
                                triac symbol

                                Susan Brown
                                Keymaster

                                  5. L1, L2, and neutral in 240 vac appliances
                                  a. How to use voltage measurements to locate the fault in an electric dryer that is
                                  not heating- disconnect one of the lead to the element and then test each wire to ensure that each line voltage is supplying power to the element

                                  Basically, yes. We’re wanting you to be familiar with basic concepts of voltage, voltage drop, and current in a series circuit, as well as L1-L2 circuits. The video at the end of Unit 6 is good to review.

                                Viewing 15 posts - 1,231 through 1,245 (of 1,948 total)