Susan Brown

[Susan Brown]

You are correct! I reset you.

[Susan Brown]

I think you have figured it out since you posted this – but just to make sure, did you see the explanation for this question?

Since the light stays on when the jumper is disconnected, the light must be getting L1 from some other source. Thus, we can conclude that H1 to L1 is not the problem.

[Susan Brown]

The only dopes are the ones who don’t ask questions when they are unsure of an answer!

“Step-by-step troubleshooting instructions” are not included on a tech sheet, although I’m sure many poorly-trained techs wish they were. There may be various amounts of guidance, but they do expect the tech to have a basic level of troubleshooting ability. Instead of that item, you should have chosen “the schematic”.

[Susan Brown]

Of your three answers for outputs, this one is wrong: “Motor speed feedback signal”

Outputs from a main control board are most often something to do with “power supply”

• This reply was modified 6 months, 3 weeks ago by Susan Brown.

[Susan Brown]

Hi Lukas,

Did you see this topic already?
https://my.mastersamuraitech.com/appliance-repair-course-support/student-forums/topic/module-5-unit-5-2/

[Susan Brown]

You have a membership at Appliantology – you can post in the Tech Forums, even if it is your own machine.

[Susan Brown]

It does take some time and practice, but you are on your way!

[Susan Brown]

Hi Andrea,

#5: The LOI *is* the “thing that ain’t doing its thing.” The LOI is NOT the component that you necessarily think is broken. If a motor isn’t running, it could be faulty, or perhaps it just isn’t receiving power due to a failed switch or board. But either way, it is the obvious item that is not functioning, and where you will start the Ten Step Tango.

#9:
They must be in continuity with each other
There must not be any voltage difference between them

[Susan Brown]

Ok, I think that makes sense.

It’s good that you are thinking this through and asking questions – keep it up! It takes time to really understand this stuff.

Am I right that the earth does not factor in with 240v? Because l1 and l2 complete the circuit?

Correct. Both L1 and L2 are “hot”, but out of phase with each other. Whenever L1 is +120v, L2 is -120v, and vice versa, so there is always a difference between them to drive current.

With Line-Neutral circuits, Line alternates between + and – 120v, while Neutral is always at 0v, which creates that voltage difference.

[Susan Brown]

Hi Clark,

You’re talking about this question, correct?

An AC circuit is properly grounded and supplied with One Million Volts. You are standing barefoot on ground and grab a hold of the bare neutral wire. What happens to you?

The correct answer is nothing.

Remember that voltage drives current. In an active 120v circuit, both sides will have current flowing, but only one side is “hot”. The hot (or “line”) side of a circuit is the side that has voltage. The neutral side is always at ground potential. There is at least one load in the circuit that divides line and neutral.

If you grab the neutral wire while standing on the earth barefoot, current will not flow through you because there is no potential difference between the neutral wire and the earth to push current through the resistance of your body.

If you were not grounded, or the neutral wire was not properly grounded, so that there was some voltage difference between the neutral wire and the surface you were standing on, then some amount of current would flow through you.

As for your last question, the neutral wire coming into the breaker box is tied to earth/ground. But that isn’t the same thing as completing the circuits within our home.

Pop quiz: Think about a 240v (L1-L2) circuit. Does the earth factor in there?

• This reply was modified 7 months, 1 week ago by Susan Brown.

[Susan Brown]

Timer contacts are a type of switch. Do you know what voltage you would expect to measure across a closed switch? (which acts just like a wire – no resistance)

[Susan Brown]

Hi Mike,
Your answer was, “58 Ω because the equivalent resistance in a parallel circuit will always be equal to the smallest branch resistance.”
That is close, but not quite right.

You also got the answer incorrect to this question:
Question #12 – In parallel circuits, the equivalent resistance will always be _____ the smallest branch resistance.

Look at the second video in Unit 5, around the 6 minute mark. Do you see what the “rule of thumb” is for equivalent resistance?

[Susan Brown]

Hi Clark,

#2 – You have a circuit with two lightbulbs in series. If one of the bulbs burns out, what change, if any, would you expect to see on an ammeter (current/amps) reading? [emphasis added]

A bulb burning out means that the filament (which is what the electrons go through) has opened. This means that current will stop flowing in the entire circuit, since it is a series circuit. (So the other bulb will have no current and therefore won’t light up.)

Make sense?

[Susan Brown]

Hi Lukas,

For Question 2, watch the video starting at about 1 min. 25 seconds.

For Question 4, he talks about this starting at about the 18 minute mark. The question is referring to where on the *diagram* is the refrigeration effect “happening”.

If you need more help, let me know.

[Susan Brown]

Hi David,
Whether you are doing the calculations yourself using the formulas or using an app, you need to understand the basics of these electrical properties and circuits in order to use them properly.

Things like:

• In a series circuit, the current is the same throughout the circuit, and is determined by the source voltage and total resistance in the circuit.
• When you have loads in series, they will have a voltage drop across them that is proportional to the resistance. In fact, the voltage drop is equal to the current times the resistance. The voltage drops will add up to equal the source voltage.
• Heat generated by a load (P) is also proportional to resistance and voltage drop across the load.

So, with the situation with the loose connection, what we are dealing with is two resistances in series. This results in a higher total resistance, thus a lower circuit current, than when the loose connection was not there.

In order to find the heat generated by just the loose connection, if you use a formula for P that involves voltage, it must the be voltage dropped across the loose connection. If you use the source voltage (e.g., 240v), then you will end up finding the heat generated by the entire circuit.

Does that help?

(I am not sure what you mean by a cheat sheet.)

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