Samurai Appliance Repair Man

[Samurai Appliance Repair Man]

The high compressor temperature can be a symptom of air in the system but it could also be caused by an internal failure of the compressor. This is actually a common problem with these LG linear compressor models.

If air were sucked into the system, you would have both high compressor and condensing temperatures. The sealed system diagnostics units, parts 1 and 2, cover this.

[Samurai Appliance Repair Man]

If you go back to around time stamp 6:30 and listen for about 30 seconds, it seems pretty clear that my comment was specifically about the simple series circuit configuration I had been talking about up to that point. My comment was clarifying that this is not a practical circuit but only used to illustrate how capacitors work in a circuit. It was supposed to be a giveaway question. 😉

[Samurai Appliance Repair Man]

Hi Soo, sorry for the delay in replying. Any heat picked up by the evaporator must be rejected in the condenser. If the condenser is at room temperature, that is bottom line proof that the system is not moving heat. The thermodynamics module went into this in detail. If the evaporator is not covered in ice or frost (insulators) then the problem is either a leak or a weak compressor. From the model number, this is a linear compressor and, given the abysmal track record with these, it is most likely that the compressor is shot.

[Samurai Appliance Repair Man]

I never got around to making a video but I do have a blog post about this: https://appliantology.org/blogs/entry/669-rigging-and-using-a-compressor-test-cord-to-manually-operate-a-compressor/

[Samurai Appliance Repair Man]

Would you be able to disconnect l1 and l2 ,from the heating element . Put the probes on l1 and l2 ( that were just disconnected)

Why disconnect L1 and L2 from the terminals? You can make this same measurement with the wires still attached. But here’s the wrinkle…

and get 240v ?

Normally, yes. BUT I asked you what reading you would get on your meter for the situation discussed in the video where either L1 or L2 are missing. You’re close, you’re almost there!

[Samurai Appliance Repair Man]

I believe it would be phase three.

I asked what you would read on your meter if you measured from L1 to L2 in the situation in the video. Your meter shows you numbers. What numbers would the meter show you?

HINT: We’re only dealing with single-phase, split-phase power here. That means just L1 and L2 which are 180 degrees out of phase and are the result of splitting a single phase into two phases, as I explain in the second video in that lesson. Re-watch if you need to.

[Samurai Appliance Repair Man]

In the last video about half splitting. Where are you putting the neutral probe ,for testing .

Not chassis and not Ground. I’ll pick any convenient unswitched Neutral as my reference.

Wouldn’t it be the same to check the back of the machine ,where the power comes in?

That would tell you about the power supply to the entire dryer but not the specific Load of Interest (the heating element). What if a wire for L1 from the terminal block to the heating element got burnt or broken? What if the wire for L2 from the motor switch head get burnt or broken? So, it can be the same but not necessarily so.

As a practical matter, you would always verify proper power supply to an appliance before disassembling to test different loads and switches. The purpose of this video was to teach an important aspect of circuits that you will run into more than once. And it has headfaked many good techs.

I have tested l1 to neutral and then l2 to neutral. Then I would both l1 and l2.would this be the same conclusion?

I’m not sure of your question. I think you’re asking that if you check from L1 to N and L2 to N would this be same as checking L1 to L2? Let me ask you: in the situation presented in the video, what would you read as your voltage phase to phase (L1 to L2)?

[Samurai Appliance Repair Man]

Which unit and module are you referring?

[Samurai Appliance Repair Man]

I apologize for not clarifying. Module 4, Gas and Electric Dryer Technologies, Unit 6 Gas Burner Ignition Systems in Dryers, first video roughly in 40 mins title Common Failure and Test. You are explaining about the valve coils failures. One of the failures are mechanical: thermal failure and that it can be expose by heating it with a heat gun. I want to know how would a thermal failure valve looks like (picture) thank you.

These failures are usually internal and therefore not visible. Could pertain to the coil wiring opening when warm or deformation of the cylinder interfering with the valve piston that the coil needs to raise.

[Samurai Appliance Repair Man]

#1 It should take 2 leads to make a voltage measurement. Voltage is a measure of potential difference between two points.

Yep!

#2 I’d say no, neutral is not a reference point in a 240 VAC. It’s just present for safety purposes?

It’s kind of a trick question. In this case, although Neutral (which is at ground potential) is not a direct reference, it is an indirect reference. The very quantity of 240 VAC would be meaningless unless we knew what 0 was.

Are we having fun yet? 🤠

[Samurai Appliance Repair Man]

First, you have to understand that all voltages are relative to some other voltage.

For example, there is no absolute 120 VAC “out there” somewhere all on its own. The earth itself has a charge relative to the sun or some other planet. But because we live on earth, we assign a voltage of 0 to the earth. So earth is the reference for all other voltage measurement on this planet.

So when we talk about voltage we’re not talking about voltage at a specific point. Instead we talk about the voltage difference between two points.

As a reminder to us that this is exactly what we’re doing, we say things like “voltage between these two points” or “voltage at this point with respect to (or relative to) some referential point.” Both mean the same thing. In the case of AC voltages, our reference is Neutral which is bonded to ground (earth) in the circuit breaker box. In the case of DC voltage, the reference is DC Ground, NOT Neutral or chassis.

Pop quiz: How many leads does it take to make a voltage measurement? Why?

Pop quiz 2: Is Neutral still a reference when making a 240 VAC measurement (L1 to L2) even though our probe is not on Neutral?

• This reply was modified 1 year, 8 months ago by Samurai Appliance Repair Man.
• This reply was modified 1 year, 8 months ago by Samurai Appliance Repair Man.

[Samurai Appliance Repair Man]

Your topic title says “Module 4, Unit 6.” But Module 4 only has two units. Could you clarify, please?

[Samurai Appliance Repair Man]

Here’s a good training video from Whirlpool explaining PWM signals with inverters. He shows both as oscilloscope display of the PWM signal as well as the reading on a voltmeter. See if this helps:

https://cfvod.kaltura.com/pd/p/1661131/sp/166113100/serveFlavor/entryId/1_s1et7f96/v/1/ev/12/flavorId/1_2i0lsaol/name/a.mp4

[Samurai Appliance Repair Man]

To your pop quiz, I believe we can also test for continuity or voltage from R to OR to check for an open in the control leg.

You win the special prize!

[Samurai Appliance Repair Man]

in the above mentioned case i just need to do IxE=P 13.2X115=1518w on the input and and there i have it!

You got it, Toyota!

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