Sam Brown

[Sam Brown]

Yep, that’s correct!

[Sam Brown]

Yes, there are both refrigerators and freezers that don’t use evaporator fans. Common examples are mini-fridges and chest freezers. They use an evaporator plate and natural air movement to disperse the cold.

[Sam Brown]

We’re talking about doing a resistance measurement here — that’s how you test a capacitor with an analog meter. And on most analog meters, 0 resistance is over on the right, with infinite resistance on the left. The needle’s resting position is at the left, on infinite resistance.

So when you first put your leads on an uncharged capacitor, it will first go to the right, reading low resistance. Then, as the capacitor charges from your meter, its resistance will get higher and higher until it becomes infinite.

Make sense?

[Sam Brown]

Sorry it took so long to get back to you! But I do have an answer regarding your question about the thermally controlled switches.

By convention, that squiggly thermally controlled symbol is always drawn below the switch. The thing that indicates how the switch responds to temperature change is actually the position of the switch itself. See the figure below:

So yes, you are correct that the switches as drawn on the schematic run counter to the convention. Flub-ups like this, especially on the finer points of schematic notation, are pretty common on manufacturer schematics, which makes it even more important for you to have a functional understanding of how the various components in appliances work.

Good spot!

[Sam Brown]

The start device is part of how the control runs the compressor, but it is not part of the compressor itself. It’s a separate component. Therefore, it is not part of the sealed system as we define it.

[Sam Brown]

Your neutral could be totally disconnected from the circuit and would still measure as a potential difference between it and L1.

That’s actually not true. If you use a loading meter (as we always say to do for AC measurements) to measure lime with respect to a floating wire like you’re describing, you won’t read 120 VAC. You would in fact read 0 VAC. The loading meter passes current through a circuit, and as you know, current cannot flow in a 120 VAC circuit without a valid neutral. The meter detects that no current is flowing and reports that you have no electrical potential between the two points.

[Sam Brown]

The FF compartment would be the first to warm up. This is because the air movement provided by the evaporator van is vital in moving cold air from the freezer into the FF compartment. With the evap fan not running, the FF will warm up relatively quickly. It will take a bit longer for the freezer to warm up, since the evaporator is in the freezer compartment.

[Sam Brown]

There’s a bit of a difference between a thermistor and a thermostat, yes.

A thermistor refers specifically to a device whose resistance changes with temperature.

The term “thermostat”, on the other hand, is used more generally to refer to any device that reacts in some way to temperature change. Oftentimes, manufacturers use the word thermostat to refer to a bimetal, such as a defrost thermostat in older types of refrigerators.

[Sam Brown]

You’re correct about the voltmeter! You would read 0 volts, because there would be no voltage drop between the two points of measurement.

With the ohmmeter, keep in mind what OL means — it stands for overload, which means that the component being measured has more resistance than the meter can accurately measure. OL is what you read when a component is completely open. A short means that a component has 0 or almost 0 resistance, just like a wire.

[Sam Brown]

When a component that normally has some resistance fails in such a way that it has much less resistance than it should, that is called a short. “Dead” here is just added for emphasis — a dead short is a short where the component has the same resistance as a strand of wire.

With that in mind, what would you read across a shorted component using an ohmmeter? What about with a voltmeter?

[Sam Brown]

The key phrase here is “polarized to do work“. Yes, all three windings have current flowing through them at any given time, but not all of them are actually doing work, i.e. pushing on the rotor in order to keep it moving. And the answer to how many that is is given in the video.

[Sam Brown]

The function of that component is to detect the temperature of the air coming out of the drum. Basically, once the air leaving the drum gets hot enough to open that bimetal, it cuts off supply of L1 to the heating coils. Then, once the bimetal cools down enough to close again, the coils begin to heat once more.

[Sam Brown]

So can I safely say that all supply voltage to thermistors for appliance would be 5 Vdc ?

That’s correct; all NTC thermistors run on a 5 VDC supply. No matter which particular model you’re working on, as long as it’s an NTC thermistor, it’s going to be the same technology and therefore operate on the same principles.

[Sam Brown]

Those aren’t actually contacts — they’re capacitors. They’re there as part of the noise filter. Current isn’t flowing through those three capacitors, so you can consider them as opens in the circuit.

[Sam Brown]

1. You’re rarely going to use safety torx, so don’t worry too much about them.. Unless you’re working on a lot of commercial appliances, don’t bother.

2. That’s just a set of thin ignition wrenches, like what you’ll use for cars. Any auto parts store should have them.

3. Those you can usually only get as bling for going to manufacturer training. They’re going to be brand-specific, and you can’t necessarily buy them yourself. You’ll just collect them (along with other little specialty tools) the more manufacturer training you go to.

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