Susan Brown

[Susan Brown]

Hi Mike,

Glad to help!

(Note that I changed the title of your topic to the unit where you scored a 70%.)

This is THE most common unit in this module for students to struggle with, so don’t feel bad.

First of all, look at Question 6. The thing that is wrong about the answer you chose is not the number. We were asking for the reading on an ammeter (also sometimes called an amp-meter). Does that mean we were looking for voltage or current?

Then for 7 and 8, we’ve got two loads in a series. I’m going to step you through this a bit with questions.

1. What is the source voltage for this circuit?
2. What do you know about the behavior of current in a series circuit?

Answer those and then we’ll continue on.

[Susan Brown]

Hi David,

It’s been awhile since I’ve watched those videos – I’m assuming this is something mentioned there. Are you talking about the tool for Miele dishwashers?

[Susan Brown]

Hi there – sorry about that. The recording is available to you here:

https://mastersamuraitech.com/webinar-recording-basic-refrigerator-troubleshooting/

[Susan Brown]

Hi Phil,

Here’s what I do. After I’ve watched it through once, I restart the video and pause at each slide to take notes. You can click ahead in the progress bar to advance to the next slide(s) without actually having to listen to all of it again, unless there are parts you didn’t quite catch the first time.

Hope that helps!

[Susan Brown]

That is correct! The one branch has a failure, of course, and current will stop in that one, which decreases the overall current draw. But the branch parallel to it will be unaffected.

[Susan Brown]

Yes, that’s correct. (I’m going to hide your answer, by the way.)

The equivalent resistance will always be less than the smallest resistance of the individual loads.

[Susan Brown]

Here it is embedded for you:

https://www.youtube.com/embed/iHB3lxdc68E

 

[Susan Brown]

That’s why we also want you to know the rule of thumb – not everyone likes to work with fractions.

Watch this video. The resistance numbers are not identical, but follow along and see if you can then come up with where your mistake is:

https://youtu.be/iHB3lxdc68E

[Susan Brown]

You’re welcome! That’s what I’m here for 🙂

[Susan Brown]

its being shunted which means its receiving current just not 120v of current correct each other load is receiving right?

Let’s make sure you are keeping current and voltage straight.

Current (in “amps”) is electrons flowing through a closed circuit.

Voltage (in “volts”) is the pressure, or charge, that gives the electrons the push to want to move in the circuit. You can have a lot of potential voltage, but if there isn’t a complete circuit, current won’t flow.

Voltage drop is a measurable voltage that is created by current flowing through a load.

In these circuits, with the detector switch closed, the main coil is shunted. If there is a path available to electrons with no resistance (no load), they will take that path 100% of the time. That is a shunt. This is what is happening here. And it results in the booster and the ignitor simply being in parallel with each other, and not in series with anything. This is why we can know the voltage drops for all of the loads in this scenario without having to actually calculate them.

By the way, when that detector switch is open, then the main coil is in series with both the ignitor and the booster, and you’d have a series-parallel situation.

Take one more look at the circuits and think it through one more time to make sure you really get it. Being able to see what is going on in a basic schematic is CRITICAL for good troubleshooting.

since the main coil is shunted off the answer for the mail coil will be 0v correct?

Correct

[Susan Brown]

Correct!

So, what do you think is happening with the main coil. Is it receiving any current, or is it being shunted?

[Susan Brown]

Correct.

Then why would any current ever go through the main coil when the detector switch is closed?

There’s a special circumstance that we talked about in Unit 5 that can cause a load to not receive any current. What is that called?

[Susan Brown]

We were posting at the same time. So let me repeat a little:

You said in one of your responses that the Booster has direct access to L1 and N (through the detector switch).

Does the ignitor have the same situation?

[Susan Brown]

In order for loads to be in series, there cannot be any alternate path that electrons can take. Is that the case with the booster and the main, based on what you just said above?

[Susan Brown]

Oops – my “yes” was to your first response

[Author]

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