A recording of the webinar held on March 19, 2015, on basic electricity. If you missed the live webinar, you can watch the recording and still partake of this cup of wisdom. Topics covered:
- The nature of electricity - Voltage - Current
This is just a small sample of what we teach in the Core Appliance Repair Training course. We go into great detail in a series of self-paced lessons explaining basic electricity, circuits, schematics, troubleshooting, motors, and much more! Enroll today!
Join Samurai Appliance Repair Man on a trek into the sealed system bowels of a warm refrigerator. Watch with amazement as I show you how to make a definitive diagnosis of a sealed system failure in this fridge using common, inexpensive tools that every appliance tech (who's worth their salt) and most DIYers already own: a clamp-on ammeter and an IR temperature gun.
Howl, o ye nations! Clap your hands, o ye peoples! No need for line piercing valves and pressure gauges IF you understand how sealed systems work, which we teach in stunning multimedia detail in the Refrigerator Repair Training Course here at the Samurai Tech Academy.
So let's look at where that current draw comes from and apply that to the compressor in the video.
Compressors are rated by horsepower. Horsepower is a measure of mechanical work. Watts are also a measure of work but the work in this case is electrical. The nameplate rating on compressors and motors gives the horsepower of the motor because you're usually interested in how much torque that motor can produce at a given voltage.
Horsepower is a measure of mechanical work just like watts is a measure of electrical work. You can convert horsepower to watts using the following conversion:
1 horsepower (hp) = 746 watts
The compressor in the video is an Embraco EGZ80HLP, a typical 1/3 hp compressor. 1/3 hp = 246 watts. Let's ignore mechanical inefficiencies in converting electrical work (watts) into mechanical work (horsepower) and run the numbers:
P= I * E => I = P / E = 246 watts / 120 vac = 2 amps
So that's where the "2 amps or maybe a little less" statement comes from in the video.
Not sure how/why I did those calculations? Ohm's law is something we teach in detail in our Core training course.
Let's compare this calculated current draw with a measured draw from the exact same compressor model (1/3 hp) in a different refrigerator, different service call, shown in the video below starting at 3:05 in, go ahead and fast forward:
I measured 1.6 amps in the video above but calculated 2 amps. Some of that difference is due to the run capacitor installed on the compressor. The purpose of the run cap is to smooth out the pulses in the motor and help it draw less current while running. But I'd say that qualifies as "2 amps or maybe a little less."
Here's another trick for diagnosing sealed systems without having to read system pressures. If you're working on a model that has a thermistor strapped to the evaporator coil (as many modern models do), then it's even easier: measure the voltage drop on the evaporator thermistor and compare with the specs in the tech sheet. Knowing that the evaporator operating temperature of a healthy sealed system is -20 to -15F, you can quickly and non-invasively tell if the sealed system is operating correctly with this one simple, electrical measurement.
See a different technique for troubleshooting sealed system problems using just your IR temperature gun in this other post.
A Master Samurai Tech Presentation: Troubleshooting Appliance Electronic Control Boards
Learn from the Samurai and become a troubleshooting master!
Using a Whirlpool dishwasher as a case study, the Samurai explains each step in the process of troubleshooting electronic control boards in appliances, revealing the schematic mysteries to all who want to learn.
In this 38-minute video, you will learn:
Basic troubleshooting techniques with broad applications to all appliances
How to use tech sheets properly
How to get those control boards to talk to you
How to identify suspected problems using the schematic diagram
How to formulate a troubleshooting strategy based on schematic analysis
How to identify where to make electrical measurements
About triac-gated neutrals in AC loads with standing voltage
The difference between loading and non-loading voltage meters and when and why to use each
...and much more!
You will have LIFETIME ACCESS to this video!
Here are a few tantalizing screenshots of the presentation...
One small price of admission gains you lifetime access to this valuable training video as well as the ability to ask follow-up questions in the comments section. Watch it as many times as you like as part of your journey to become a Master Samurai Tech!
Here at the Samurai Tech Academy, we're always thinking about our students! (That's not quite as creepy as it sounds.)
In yet another example of the STA's devotion to the needs of our students, we have added new Module Exams to most of the modules in the technical courses. Many of you were asking for more challenges along the way to make sure you're really getting the material. Module Exams are a great way to revisit the info from all of the units you've studied and make sure you've nailed it before moving on to a new module.
IMPORTANT: if you are currently working through Core training or Refrigerators, you will have to go back and take any exams for modules you've already completed before you can move forward. I hope you will see this as an opportunity to review and practice the material from those modules, and know that it will help you when you get to the Final Exam!
If you have already completed either course, you can still go back and take the exams for funsies!
But wait! There's more!
Another change we made was a three-attempt limit on the quizzes that come after each unit (lesson). We did this because if a student needs to re-do a quiz more than three times, there's something wrong either with the student's attention to the material presented in the unit or with the way the material is presented. Either way, we need to troubleshoot that!
So here's the drill: if a student requires more than three attempts to pass a quiz (and all unit quizzes require a score of 100% to pass and move on to the next unit) then the software sends me an email and the student's progress is temporarily stopped until we can talk either by phone, email, or the Student Forums.
After I've administered the appropriate gray matter massage, the student is re-enabled to re-take the quiz and continue on their merry way. Ultimately, the goal is to encourage more student-Samurai interaction as needed to help the student master the material.
When enrolling technicians in an MST Academy appliance repair training course, most business owners will do the registration/enrollment process themselves so that they will have the username and password for each tech, and can therefore log in as desired to check on a tech’s progress.
This is how to enroll a tech for their first course or bundle. If they are a returning student, see Note #4 below.
1. Make sure you are NOT logged in (check the upper right hand corner of the site).
3. Select the course or bundle you want from the pull-down menu box.
4. Now enter your discount code, if you have one.
5. Create your tech’s profile - First and Last name, email address, username, password. (See notes below.)
6. Click "Add Billing Method" at the bottom of the Billing Method section of the enrollment form and enter your credit card information.
7. Click the red "Submit Form" button. (The receipt will be emailed to the student email address - have them forward it to you!)
That’s it! The tech is ready to log in and start his Journey of Total Appliance Enlightenment! If you have more techs to enroll, simply go back to Step 1.
1. Once you create a profile, the username cannot be changed. All of the other items can be changed, if needed.
2. Each email address must be unique, in other words, one per student.
3. If the tech’s email address has already been registered at the site (for example, to take the Sample Course), then you can’t do a new registration with that email. You can either use his existing registration (get his username and password, log in to the site with them, then enroll in a course) or contact us and we can delete his old account and you can start fresh.
4. To enroll a tech in additional courses in the future, simply log into his/her account first, then Enroll as described above. You won't have to create the student profile - those spaces will be automatically filled.
5. Taking our courses is a very personalized experience for each student, so each technician needs his or her own enrollment in each course. For online training to be effective, students need to work at their own pace and be encouraged to repeat lessons and videos as needed. The goal is mastery of the material, after all! And each tech comes to their training with their own unique mix of strengths, weaknesses, and experience.
If you have any questions at all, please contact us!