تدريب Shadowing: 120V 240V Electricity explained - Split phase 3 wire electrician - تعلم التحدث بالإنجليزية عبر الفيديو
اختر وضع التدريب
كل وضع يفتح غرفة تدريب بملء الشاشة.
169 جمل
إذا كانت الجمل قصيرة أو طويلة جدًا، انقر على Edit لتعديلها.
1
Hey there guys Paul here from TheEngineeringMindset .com.
2
In this video we're going to be learning how three wire split phase electricity supplies work to get 120 and 240 volts.
3
We'll look at how the electricity gets from the power station over to the property
4
and then how it's connected around the property and each of the main components.
5
Now this system is used in North America us will be using their terminology
6
and color coding if you're from outside this region then you can still follow along
7
but your electrical system will work differently we've covered
8
that in a separate video do check
9
that out links are in the video description down below remember electricity is dangerous
10
and can be fatal you should be qualified
11
and competent to carry out any electrical work so electricity is generated at the power station which is usually located far away.
12
The power station generates AC alternating current and is connected to a step up transformer.
13
This transformer increases the voltage to reduce losses and is connected to the grid.
14
The grid carries high voltage electricity over long distances over to the towns and cities.
15
Once it reaches the towns and cities it will enter a step down transformer
16
which will decrease the voltage to a safer level.
17
From here it will be distributed locally into smaller circuits on on different streets or groups of properties.
18
Connected to these distribution cables will be smaller transformers,
19
usually pole -mounted, which again reduce the voltage down even further to a level safe enough for residential use.
20
On the property will be an electricity meter
21
which will quantify how much electricity has been used and the electricity company will use this to invoice the property.
22
The transformer will be connected to the electricity meter by some cables which will either run above ground or underground.
23
these cables will be two hot wires
24
and a neutral wire inside the transformer
25
we have two coils of wire the primary coil is connected to the power station
26
and the second coil will be connected to the property the
27
two hot wires are connected to each end of the secondary coil
28
and the neutral is connected to the center of the coil now don't worry about
29
that too much for now we're going to look at this again later in the video to understand it
30
so if we zoom into the property we find a main service panel
31
which is sometimes called a load center or breaker box.
32
If we remove the cover and look inside we first find the main breaker.
33
This is usually at the top of the panel but it might be at the bottom.
34
The two hot wires from the electricity meter will connect directly to the lugs on the main breaker.
35
Coming out of the main breaker will be two main bus bars.
36
These are basically exposed metal sheets
37
which carry electricity to the circuit breakers notice i've shown the current flowing backwards
38
and forwards that's because this is ac
39
or alternating current these bus bars as well as the lugs are not insulated they are live or hot
40
the main breaker can be manually flipped to cut the power
41
to everything downstream of the main breaker the main breaker will also provide over current protection to the property
42
it is rated to handle a certain amount of electrical current passing through it typically between 100 and 200
43
If this value is exceeded then it will trip automatically to try and protect the property and its electrical circuits.
44
Inside the panel we also have a neutral and ground bus bar.
45
This is basically a strip of metal with lots of holes and screws in it.
46
The neutral and ground wires will sit in the holes and the screws will lock them in place.
47
In this example we have a block on either side of the panel.
48
As this is a main panel the two bus bars can be joined together
49
so so we have a connector bar between them.
50
That way we have a shared neutral ground bus bar.
51
Sub panels must have their bar separated, but that's a topic for a separate video.
52
From the electricity meter, we will have the neutral wire connected to the lug on the top of the neutral ground bar.
53
Notice the green screw.
54
This is bonding the neutral bar to the metal casing of the service panel.
55
The purpose of the neutral bar is to return the used electricity back to the transformer.
56
It does actually get a little bit more advanced than that, but we're going to look at that in a more advanced complex video.
57
This is just covering the basics.
58
So the two hot wires will provide electricity
59
and once it is used it will return to the transformer via the neutral bar.
60
It is still AC alternating current
61
but to make it easier to visualize I've only animated the current flowing in one direction
62
so you can see the path it will take.
63
Now if we were to take our multimeter
64
and connect one lead to the bus bar
65
and the other lead to the neutral bar we would get a reading of around 120 volts.
66
If you don't already have a multimeter, then I highly encourage you to get one for your toolkit.
67
It's essential for any electrical testing and fault finding.
68
Links down below for which one to get and from where.
69
If we connect the multimeter leads to the other bus bar and the neutral bar, we would again get a reading of around 120 volts.
70
But if we connect the multimeter leads to the two bus bars, then we get a reading of double that at around 240 volts.
71
So why is that?
72
What's happening here?
73
So when we look at how the transformer is connected to the main panel,
74
we have the two hot bus bars connected to either end of the secondary coil in the transformer.
75
And then we take the neutral bus bar connected to the center of the secondary coil.
76
So basically, when we connect across the bus bar and the neutral bar, we're only using half of the coil
77
so we are only picking up half the electrical voltage the transformer can provide so that way we get 120 volts.
78
When we connect to the two bus bars we're connecting to the full length of the coil
79
so we're picking up the full voltage which the transformer can provide therefore we get 240 volts.
80
If you want to learn how transformers work then check out our video on transformer basics links for
81
that down in the video description below.
82
Now coming back to the panel connected
83
Connected to the bus bar, we'll have our circuit breakers.
84
These will look something like this with this black plastic casing and a toggle switch on top.
85
The circuit breaker controls the flow of electricity into individual circuits in the property.
86
It can be manually tripped to cut the power, but it also has two important features.
87
The first feature is overload protection.
88
The circuit breaker is rated to handle a set amount of electrical current.
89
When appliances or lights are connected to the circuit, they will each increase the current in the circuit.
90
If too many things are plugged in and turned on, then eventually the current will be more than the breaker can handle
91
and the breaker will automatically trip to cut the power off to the circuit and protect the property.
92
The second feature is short circuit protection.
93
When the hot and neutral come into direct contact with each other, the current will dramatically increase almost instantly.
94
When this occurs, it creates a magnetic field which will trip the breaker and cut the power automatically.
95
Let's have a look at how the circuit breaker is connected to the electrical circuit.
96
In this example we will connect to a simple light fitting which is controlled by a switch.
97
We take the hot wire from the circuit breaker and run this to the switch.
98
We then run another wire from the switch and over to the light fitting.
99
From the light fitting we have a neutral wire which carries the return current back to the neutral bus bar.
100
We take the ground wire from the metal casing of the ceiling box in the switch
101
and we also join this to the neutral bus bar as in this case it's shared.
102
The purpose of the hot wire is to carry the electrical current over to the light fitting.
103
The purpose of the neutral wire is to carry the used electrical current back to the main panel
104
and then back to the transformer.
105
The purpose of the ground wire is to provide protection for a fault current.
106
If for example the hot wire came loose
107
and touched the metal casing of the light fitting the ground wire provides a low resistance path back to the panel.
108
Without this path electricity could flow through you if if you touch the metal box.
109
As the current flows through the ground wire, it will increase the current and that will trip the breaker automatically.
110
So the electricity flows through the hot wire, through the main breaker, down the main bus bar and into the circuit breaker.
111
From there, it flows along the hot wire, across the switch and light, then back along the neutral wire and into the neutral bus bar,
112
along the neutral bus bar wire and back to the transformer.
113
I've animated this using AC alternating current, but to make it easier to understand the path, I've shown it flowing in a single direction now.
114
We've covered lighting circuits in detail in a separate video, do check that out, links in the video description below.
115
Okay so what else might we find here?
116
Well we might find a double pole circuit breaker
117
which will let us connect to both bus bars to get 240 volts
118
which we can use to power larger appliances like dryers, ranges and air conditioning units.
119
If we look at the dryer circuit example we run the red hot wire from the circuit breaker
120
which is connected to the main bus bar number two and we run this to the receptacle.
121
Then we run our black hot wire from the other terminal of the circuit breaker
122
which is connected to bus bar one and we connect that to the receptacle also.
123
In this case we have the neutral wire connected between the neutral bus bar
124
and the receptacle which will allow us to get either 120 or 240 volts from the outlet.
125
Then we have a ground wire to provide a safe route for any fault current.
126
Now we can either connect across the two hot wires for our 240 volt connection
127
or between the hot wire and the neutral wire to get 120 volt connection.
128
We'll also very likely find a GFCI circuit breaker which stands for ground fault circuit interrupter.
129
This will look something like this
130
and depending on the model you buy you will usually have a pigtail neutral wire connected to it.
131
GFCIs are required on certain circuits where outlets are used for places like kitchens,
132
bathrooms, hot tubs etc. You should check with the National Electric Code for exact details.
133
The GFCI breaker has both the hot and the neutral flowing through it.
134
This way you can measure the current flowing through both wires and ensure they are equal.
135
If we took a standard outlet, we would take a hot wire from the breaker and connect this to the outlet terminal.
136
Then we take the neutral wire and run this back directly to the circuit breaker to a specific neutral terminal.
137
We then connect the pigtail wire into the neutral bus bar.
138
This will provide the return path.
139
And of course we run the ground wire from the outlet back to the neutral ground bar.
140
If we look at this example, the current is flowing normally until the guy sticks a screwdriver into the socket.
141
The electricity then flows through him instead of the neutral wire.
142
The GFCI is measuring the current in the two wires and notices that these are not equal.
143
It then automatically trips the breaker to cut the power and save the man's life.
144
We might also come across an AFCI circuit breaker.
145
This stands for arc fault circuit interrupter.
146
These are required for circuits feeding bedrooms, hallways, kitchens, et cetera.
147
Again, check with the National Electric Code for exact details.
148
AFCIs work also by being connected to both the hot and neutral wires.
149
Inside this circuit breaker is a circuit board, which is measuring the circuit and monitoring for patterns which indicate an arc fault is occurring.
150
These are installed pretty much identically to how we saw the GFCI breaker.
151
Under normal conditions the current flows through the hot, back through the neutral, into the breaker, then through the pigtail and back through the neutral bar.
152
But if for example a screw was accidentally inserted very close to the cable
153
and removed the insulation to expose the copper wires, the electricity could now potentially jump across or arc from the hot wire and into the neutral.
154
The arc is incredibly hot and causes most residential electrical fires.
155
As the arc occurs it creates a unique signal in the electrical cable.
156
The circuit breaker can detect this and will automatically trip to cut the power.
157
Connected to the neutral ground bar will be a thick uninsulated copper wire
158
which runs out of the bottom of the panel
159
and off to the ground rod which is pushed into the earth near the property.
160
Under normal circumstances no electrical current will flow through this wire
161
its purpose is to dissipate high static voltages from things like lightning this way the electrical systems
162
and equipment is protected from damage additionally we'll also find a bonding wire to metal pipe work in the property
163
this is to provide a safe route for electricity to flow
164
should a hot wire come into contact with a metal pipe
165
and this way it will prevent a person being electrocuted
166
if they were to touch the pipe work okay guys that's it for this video
167
but if you want to continue your learning then check out one of the videos on screen now
168
and i'll catch you there for the next lesson.
169
Don't forget to follow us on Facebook, Twitter, Instagram, as well as
تنزيل التطبيق
كل ما تحتاجه للتحدث بطلاقة
تقييم النطق بالذكاء الاصطناعيتقييم كل جملة
تدريب IPAأتقن كل صوت
المفرداتابنِ رصيدك من الكلمات
لعبة المفرداتتعلّم أثناء اللعب
نفس القناة
B21
Ohms Law Explained - The basics circuit theory
Daily ConversationUniversity Students
C11
Diodes Explained - The basics how diodes work working principle pn junction
Daily ConversationUniversity StudentsWorking Adults
B21
Air Conditioning System Basics hvacr how does it work
Daily ConversationWorking Adults
B22
How ELECTRICITY works - working principle
Daily ConversationUniversity StudentsWorking Adults
C1Centrifugal Pump Basics - How centrifugal pumps work working principle hvacr
Daily ConversationWorking Adults
FOR YOU
فيديو موصى به
C11
95 جمل
26 - How does harmonic phase shifting work including a detailed mathematical explanation to reduce s
Daily ConversationUniversity Students
C11
51 جمل
What's Under Your Feet in New York City?
Daily ConversationUniversity StudentsWorking Adults
C11
118 جمل
Current | Introduction to electrical engineering | Electrical engineering | Khan Academy
Daily ConversationUniversity Students
C11
59 جمل
How does a Thermal power plant work?
Daily ConversationUniversity Students
C12
40 جمل
Inside the Relay Controlled SF6 Circuit Breaker: Preventing Arcs and Ensuring Safety
Daily ConversationUniversity StudentsWorking Adults
C11
132 جمل
Helpdesk to Sysadmin - 3 Things You Must Learn First
Daily ConversationUniversity StudentsWorking Adults
C11
19 جمل
I Made an EMP Device... It Actually Works
Daily ConversationUniversity StudentsWorking Adults
C11
153 جمل
Statics: Lesson 46 - Distributed Loads Using Centroids
Daily ConversationUniversity Students
C13
279 جمل
LET THERE BE... Voltage? | Maxwell's Equation #2 Explained for Beginners
Daily ConversationUniversity Students
C12
175 جمل
What is a PLC and how does it work?
Daily ConversationUniversity StudentsWorking Adults
C11
113 جمل
Architectural Design Process Explained
Daily ConversationUniversity StudentsWorking Adults
المفردات وملاحظات التحدث لهذا الدرس
هذا الدرس في المحادثة مبني على الفيديو “120V 240V Electricity explained - Split phase 3 wire electrician”. أكثر الكلمات تكرارًا في الفيديو: wire, neutral, bar, breaker, circuit. يحتوي هذا الفيديو على 169 جملة و2404 كلمة للتدرب على الترديد. مدة الكلام 12:10. يتكلم المتحدث بسرعة، نحو 198 كلمة في الدقيقة، لذا ستسمع كثيرًا من وصل الكلمات واختزال الأصوات. 79% فقط من الكلمات ضمن أكثر 3,000 كلمة شيوعًا في الإنجليزية، فالمفردات صعبة نسبيًا.
أهم المفردات في هذا الفيديو
15 كلمة من الفيديو تستحق التعلّم، مع النطق والمعنى:
| الكلمة | النطق | المعنى |
|---|---|---|
| wire اسم | /ˈwaɪɚ/ | سِلْك |
| neutral صفة | /ˈnuː.tɹəl/ | مُحَايِد |
| connect فعل | /kəˈnɛkt/ | رَبَطَ |
| coil اسم | /kɔɪl/ | مِلَفّ, وَشِيعَة |
| voltage اسم | /ˈvəʊltɪd͡ʒ/ | جُهْد, فُولْتِيَّة |
| metre اسم | /ˈmiːtəɹ/ | مِتْر |
| occur فعل | /əˈkɜː/ | حَدَثَ, وَقَعَ |
| pipe اسم | /ˈpaɪp/ | مِزْمَار |
| residential صفة | /ˌrɛzɪˈdɛnʃəl/ | سَكَنِيّ |
| copper اسم | /ˈkɒpə/ | نُحَاس, نحاس |
| pole اسم | /pəʊl/ | قُطْب |
| grid اسم | /ɡɹɪd/ | شَبَك, شَبَكَة |
| rat اسم | /ɹæt/ | جُرَذ, فَأْر |
| topic اسم | /ˈtɑpɪk/ | مَوْضُوع, مَوَاضِيع |
| lesson اسم | /ˈlɛs.ən/ | دَرْس, حِصَّة |
الأفعال المركبة التي ستسمعها
| الكلمة | النطق | المعنى |
|---|---|---|
| pick up فعل | قَطَفَ | |
| carry out فعل | /ˈkæ.ɹi aʊt/ | شَغَّلَ, نَفَّذَ |
| pass through فعل | اِخْتَرَقَ, نَفَذَ |
القواعد في هذا الفيديو
أكثر التراكيب التي يستخدمها المتحدث، مع العبارات نفسها من الفيديو:
| التركيب | في الفيديو |
|---|---|
| المبني للمجهول be + اسم المفعول — التركيز على ما يحدث لا على من يفعله | is used · is generated · is connected |
| جمل الوصل who / which + جملة — معلومة إضافية عن شخص أو شيء | station which is · cables which will · field which will |
| المضارع التام have/has + اسم المفعول — حدث ماضٍ ما زال له أثر الآن | we've covered · has been · i've shown |
نطق يحتاج إلى انتباه
يستخدم المتحدث 21 من الصيغ المختصرة، مثل we're, I've, we'll. انطقها بصيغتها القصيرة كما تسمعها.
- أصوات “sh” و“zh”: residential /ˌrɛzɪˈdɛnʃəl/, sheet /ʃit/, potentially /pəˈtɛnʃ(ə)li/, insulation /ˌɪnsəˈleɪʃən/, visualize /ˈvɪʒuəˌlaɪz/
- الكلمات الطويلة — انتبه لموضع النبر: electricity /ɪˌlɛkˈtɹɪsɪti/, electrical /ɪˈlɛktɹɪkəl/, residential /ˌrɛzɪˈdɛnʃəl/, manually /ˈmænj(u)əliː/, potentially /pəˈtɛnʃ(ə)li/
أصوات يجدها متحدثو العربية صعبة:
- /p/ — ليس /b/: انطقه مع نفخة هواء: pipe /ˈpaɪp/, copper /ˈkɒpə/, pole /pəʊl/, expose /ɪkˈspoʊz/, topic /ˈtɑpɪk/
- /v/ — ليس /f/: مع اهتزاز الأوتار الصوتية: voltage /ˈvəʊltɪd͡ʒ/, volt /vəʊlt/, invoice /ˈɪnˌvɔɪs/, overload /ˌəʊvəˈləʊd/, screwdriver /ˈskɹuˌdɹaɪvɚ/
- تتابع الصوامت — لا تضف حركة بينها: connect /kəˈnɛkt/, breaker /ˈbɹeɪkɚ/, electricity /ɪˌlɛkˈtɹɪsɪti/, electrical /ɪˈlɛktɹɪkəl/, grid /ɡɹɪd/
كيف تتدرب بهذا الفيديو
- استمع إلى الفيديو كاملًا مرة واحدة دون أن تتكلم، ودوّن الكلمات التي لا تعرفها.
- ابدأ بسرعة 0.75×، وردّد جملة جملة، ثم عُد إلى السرعة العادية عندما يصبح الأمر سهلًا.
- سجّل صوتك وقارنه بالأصل، مع الانتباه إلى كلمات مثل wire, neutral, connect.
ما هي تقنية التظليل الصوتي؟
التظليل الصوتي (Shadowing) تقنية تعلم لغة مدعومة علمياً، طُورت أصلاً لتدريب المترجمين الفوريين المحترفين. الطريقة بسيطة لكنها قوية: تستمع لصوت إنجليزي أصلي وتكرره فوراً بصوت عالٍ — كظل يتبع المتحدث بتأخير 1-2 ثانية. تُظهر الأبحاث تحسناً كبيراً في دقة النطق والتنغيم والإيقاع وربط الأصوات والاستماع والطلاقة.