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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?
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.
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.
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.
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.
April 15, 2020 at 12:31 am in reply to: Module 2 Unit 2 Your Tool Backpack – few extra tools recommendation #189261. 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.
April 15, 2020 at 12:27 am in reply to: Module 2 Unit 1 List of Basic Tools – few questions regarding tools #18925I’ll go through your list one at a time.
1. We don’t recommend any specific impact socket set. They’re basically all created equal, and you probably won’t be using them all that much anyway.
2. Same idea with the drill bit set. No need to seek out a particular brand — just find a set that works for you. We tend to like bits that have hex bases, so they can easily be slid on and off of the drill as needed.
3. The 116 and 117 meters are both great, and as you noted, the only difference between them is that the 116 has the thermocouples. If you already have a good temperature meter, then go for the 117. If not, then go ahead and spring for the 116.
4. We use a Klein infrared temperature reader — bought it at Home Depot, actually. But again, there’s no need to go for a specific brand. Just find one that seems reliable and has the features you want.
Hi Darren,
Looks like the Samurai just misspoke around 13:28. He meant to say that AC asynchronous motors are designed to slip and make horrible timers. Just a little slip of the tongue (pun intended). Good noticing!
Could you give the timestamp of the portion of the video that you’re referring to?
I’m assuming that you’re talking about the ignitor in a dryer, since you posted in the Washer and Dryer forum. If that’s not the case, let me know.
You said:
As the ignitor ages, it weakens and, it’s resistance starts to decrease.
Actually, the opposite is true. The resistance of the ignitor increases as it ages. Once the resistance gets high enough, the ignitor will not get hot enough to satisfy the flame detector, and the gas valve will not allow gas to enter the burner.
Flame rectification has no bearing when you’re talking about ignition in dryers. That only occurs in direct spark reignition systems, such as what you find in some cooktops.
Yep, that definitely sounds like how that cycle was designed to run. The engineers would have done lots of testing and specified the components (such as the operating thermostat) to allow the cycle to complete roughly around the time when the clothes are dry.
Without being able to look at the start device myself (beyond the picture at Amazon), it’s hard to say for sure. I do see a label that says “CAP” by the two terminals I think you’re talking about. That would indicate to me that those terminals are for connecting a capacitor. But again, without knowing more, I can’t say for sure.
Multi-point ignition means that you have one spark module which sends sparks to multiple burners. Single-point ignition means that you have one spark module per burner. So the easy way to tell if you have single or multi-point ignition is simply by looking at the number of spark modules shown on the schematic.
Is there a particular schematic that you’re confused about? If so, let me know which unit it’s in.
The purpose of an impact driver is to remove fasteners that are stuck or otherwise difficult to make turn. For example, they’re often used on washers to remove the main drive or bearing nut.
December 6, 2019 at 8:34 pm in reply to: Mod 3, Unit 10, splicing Cu with non-Cu and connectors #17784If the conductor isn’t copper, then it would be aluminum. But I highly doubt that it is. Much more likely that it’s copper that’s tinted silver — manufacturers do that sometimes. The way to tell is to cut the wire and look at the cross section. If it’s copper, you’ll see that the silvery color is only on the surface.
If it really were aluminum, then yes, you would need special materials to make the splice, since copper and aluminum corrode each other. They make a special goop for aluminum to copper splices to prevent this.
It sounds like you’re using a voltage light stick or something similar to find the break in the cord. That’s going to be very difficult to do, since those devices aren’t designed for precise measurements. It sounds like you’re already getting false readings — you should not be picking up voltage anywhere on the neutral side. The sensor is probably just picking up the field from the voltage on the line side of the power cord.
To find the break, you’ll want to do an ohms/continuity test with you meter. You’ll want to open up the iron to do this so that you can get to the terminal where the power cord connects to the rest of the device.
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