August 2015
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In my last post i talk about the compressor overload and in this post you will learn about PTC Relay which we use mostly for every refrigerator compressor starting. PTC means positive temperature coefficient thermistor however we can called starting relay or compressor starting relay in simple words.


How a Refrigerator PTC Relay Working and Function

In the refrigerator compressor we use the split phase single phase induction motor  and this motor have internal two types of winding which we called running and starting winding or auxiliary winding. We know that a single phase motor did not start without starting capacitor or a staring current.
In simple words the refrigerator ptc relay gave a current to start winding and when the motor stat up the ptc compressor relay remove the start winding from the circuit.
So the above is a simple and short explanation of refrigerator relay and it's working, So lets know the working method of a PTC.

refrigerator ptc relay
Compressor starting relays


As i written above that ptc mean positive temperature coefficient thermistor which means that a relay with working relation with temperature. Basically a ptc thermistor is a resistor whose resistance increase with increase of temperature.



So let's explain it step by step
We know that compressor motor or fridge compressor have split phase induction motor which have two types of winding, the main winding which we called him RUN Winding  and the auxiliary winding which we called START Winding. A fridge compressor required a starting current to start normally and for this we connect the starting relay.
Compressor three terminals called START, RUN and COMMON. Common means the point where the start and run is connected.

Also read
What is working of capacitor in single phase motor
What's Overload and How a overload protector works
Internal structure of induction motor winding connection

How to identify refrigerator compressor terminals

We connect overload protector to compressor common terminal and ptc relay to the run and start terminal. In ptc relay the supply goes direct to the run winding but between supply and start winding a thermistor is connected in series and when we switch on the refrigerator the current start flowing through the thermistor to auxiliary and compressor start up, this current flow heat thermistor and due to temperature the resistance of thermistor high and thermistor remove the start winding from supply.
E.g Example : If you start you fridge and then you switch off and then start it, you will notes that the compressor is not start again because of heat thermistor or relay. And when you switch off again and try after 5 to 10 minutes you will find the fridge compressor start normally.

In many cases we connect a staring and running capacitor to the ptc relay which help very much in staring compressor. With starting capacitor we connect ptc relay thermistor in series which make remove of start capacitor from the circuit. In many ptc compressor relay have a connection point for run capacitor and we connect the run capacitor in parallel with relay which help in better staring and running compressor.

Message :

I hope you learn some thing from this post about the ptc compressor staring relay and it's working, however i will guide you about all types of ptc relays and it's wiring methods with complete diagrams.
A platform to learn electrical wiring, single phase, 3 phase wiring, controlling, HVAC, electrical installation, electrical diagrams.
Welcome back to the refrigerator topic, and in this post we discus the overload protector which we use to protect refrigeration compressor. In this post you will learn the function of overload protector and it's working principles.

What is overload protector and it's function in refrigerator and air conditioners.


A overload protector is an electrical device which we use for compressors protection, whenever the compressor temperature high from his range the compressor overload cut off the electric supply from compressor motor that's why we called him thermal overload.
The connection of overload with compressor in series and inside the overload we connect a heating resistance and with heating resistance we connect a bimetallic strip metals. The heating resistance and bimetallic strip metals both make a overload relay.
The working of overload relay is simple whenever the compressor motor getting heat up, due to the overload connected with the compressor body, the internal overload heating resistance heat up and due to heat up the bimetallic strip metals cut up the connection between one another and its make  comprssor circuit to a open electric circuit. When the compressor come back to his normal state/temperature, the thermal overload protector make a close electric circuit inside, and connect the electric supply to the motor.

Note that compressor is getting heat by flowing a high amount of current, however if compressor getting normal current (Ampere) and it is  heating, then also Overload protector will be trip or make open circuit if it's connected with compressor body.

The cut off the supply overload make safe compressor motor from internal winding damages/ burned. However you will not understand the working principles of overload with out a diagram. That's why i designd a diagram about the internal structure of a thermal overload protector.

overload protector diagram


In the above figure, i shown overloads 2 types and i lights it's terminals with the name of IN and Out. The (IN) means that we gave electric supply to this terminal and (Out) means that we get electric supply for compressor or we can say that this point is goes to connect the compressor common terminal.

Also read
How to find out Start,Run,Common terminals in a Compressor

I also shown a internal structure of overload in above example diagram. In diagram i shown the bimetallic strip metals with heating resistance with incoming and outgoing supply. When ever the compressor start getting high current the heating resistance heat up and create an open electric circuit.
This one of main reason that we use thermal overload protector in refrigerator compressor, i hope you will get a good information from this post, however we will soon discus the main reason of compressor getting high current or heat up.
A platform to learn electrical wiring, single phase, 3 phase wiring, controlling, HVAC, electrical installation, electrical diagrams.
In my last post i share a diagram about making series testing board but my last diagram about series board which is only for connectivity testing, shortage testing, or compressor terminals testing but in this post you will learn that how can you make a testing board, from which you can test the low resistance electrical appliances such as Electric heater, iron etc.

Requirements:

For making or wiring this type of testing board you will require the below electrical substances.
2 Pin socket or Electric outlet
One way switch
bulb socket / bulb holder
Incandescent light bulb

How to make series testing board for low Resistance appliances testing


A platform to learn electrical wiring, single phase, 3 phase wiring, controlling, HVAC, electrical installation, electrical diagrams.
My this post is about the series testing board which we can use in those places where we did not available other electrical testing device. It is the oldest but one of the best method of testing electric appliances or devices. In many places where we have not a multimeter and we required to test electric motor or other connectivity test then we can use series testing board which very simple to wire or make however we can not test all things but the necessity  is the mother of invention.


A platform to learn electrical wiring, single phase, 3 phase wiring, controlling, HVAC, electrical installation, electrical diagrams.
In my last post i guide you about the ammeter wiring which is only for low load and in this article you will learn that how to wire ammeter for high load or High ampere testing. In this post i am sharing with you a diagram in which i wired an ammeter with current transformer which is well know with his short name CT Coil.
By using the ammeter and CT coil we can measure high load ampere, Note that we use this wiring method for power wiring and by using this ammeter wiring we can test, measure high load circuit or ampere.

A platform to learn electrical wiring, single phase, 3 phase wiring, controlling, HVAC, electrical installation, electrical diagrams.
In my last post i written about the ammeter and now this post is about ammeter wiring , In this post i will completer guide you about the ammeter wiring and it's wiring diagram which i design for those student how can not learn from difficult diagrams.
In this article we clear some most important question which make a problem for electrical student. I always try to tech student with advance and easy way.

Also Read below
what is ammeter or ampere meter and role of am meter

How to Wire an Ammeter or Ampere meter

We know that the flow of electron in electric circuit is called current and current is denoted by I and it's unit is Ampere Which we denoted by "A". 
Note ammeter wiring is always in series connection but this is only for low load, For high load measure or testing ampere we use the CT coil with ampere meter to measure the A.
In this article we talk about low load, and for low load we wire ammeter in series with circuit.
In below diagram i shown that how to wire amp meter, in the diagram i shown two wire coolers in which one is Black and second is Red. You called this black and red cooler wires positive and negative for DC (Direct Current) or you can also called these coolers neutral and Phase for AC (Alternative Current).
A platform to learn electrical wiring, single phase, 3 phase wiring, controlling, HVAC, electrical installation, electrical diagrams.
Ammeter is will know with the name of ampere meter which is an electronic measuring instrument which is used to test or measure the ampere in a circuit. This article is about the ammeter and it''s types and function, how ever in our incoming post we will explain the the wiring of am meter further.

What is an Ammeter?

As i written in my above words that it is an electronic device which we use for testing the current in electric circuit. This device help us to know about the current (ampere) getting a circuit. Or we can said that we can test the consumption of electricity of a electric circuit using the ammeter.
Note that when in one second one coulombs of electron flow form a point is called the one ampere (A).

A platform to learn electrical wiring, single phase, 3 phase wiring, controlling, HVAC, electrical installation, electrical diagrams.
We use three phase motor mostly in many places, in this post you will learn the 3 phase motor wiring with complete circuit breaker, contactor and overload relay diagram with step by step. We required some electrical things for three phase motor wiring which are below.

Requirements

3 phase induction motor
3 core electric cable
Three phase 4 wire system supply (three phase and one neutral)
A circuit breaker
A contactor or stater
A overload relay
and flexible wiring cable for cotactor coil and button wiring
Normal close push button
Normal open push button


Before we starting talking about the wiring and wiring diagram, first we disuse the above substance . We required 3 core cable, a three core cable is a cable which have internal three electric cable which mostly in red, yallow and blue colors. The three phase 4 wire system supply means that we need 3 phase electric supply and one neutral wire. Note that we use the neutral wire for contactor coil wiring which we called the small wiring.
We also required the circuit breaker which are 3 pole circuit breaker or circuit breaker which can cutoff the 3 electrical connection in same time.
Normal close push button (NC) means that we need a push button which is normally have close electric circuit and when we push it then the button switch off the connection or change to the open electric circuit.
Normal open push button mean that we need a push button which have a open electric circuit in normal state and when we push it then it's change to the close electric circuit.

3 Phase Induction Motor Wiring with Contactor Wiring Diagram

To wire a 3 phase motor the first thing to wire is a circuit breaker which is disconnect and connecting point then we will get the supply from circuit breaker and connect supply to contactor or starter and then to overload relay. We connect the circuit breaker, contactor and overload relay in series between electrical supply and motor as shown in below diagram.

3 phase motor wiring diagram
power wiring

Update Diagram For Direct Online starter So use the diagram.


dol starter wiring diagram


Contactor and overload Wiring


A platform to learn electrical wiring, single phase, 3 phase wiring, controlling, HVAC, electrical installation, electrical diagrams.
In my last post i share a 3 pin socket wiring diagram, in this post you will learn that how to wire a switched 3 pin socket or how to control a 3 pin socket from a circuit breaker. This wiring diagram is impotent because by using this wiring connection a person can easily switch off the 3 pin socket or can easily switch on by using the circuit breaker


How to wire 3 pin socket with circuit breaker

To wire a switched three pin socket, first of all connect the earth wire to E connection of socket and then connect the Neutral wire to N point of socket and connect the Phase wire to circuit breaker and then connect a wire between circuit breaker output terminal and socket L or P terminal as show in below diagram.

3 pin socket wiring with circuit breaker
three pin socket

A platform to learn electrical wiring, single phase, 3 phase wiring, controlling, HVAC, electrical installation, electrical diagrams.
Today in this post you will learn about 3 pin socket wiring which very useful wiring connection in home wiring. In this post i am sharing with you three pin socket or electrical power outlet wiring diagram.


Why three pin socket wiring connection is important

Because this is a power socket and we can use it for high load.This outlet have earthing point we can wire the earth wire with this socket.

How to Wire 3 pin socket

In three pin socket we have 3 connecting point where we connect the supply wires or electric wires. These are E,N,L connection. In these E for Earth wire, N for Neutral wire, and L for Phase wire.
So to wire the power socket first of all switch off your incoming supply by using the main circuit breaker and the start wiring.

Also read.
How to wire a two pole circuit breaker

After switching off the breaker connect the neutral wire to the N point, Phase wire to P or L point and Earth wire to the E point as shown in below diagram.

3 pin socket wiring diagram
3 pin socket



I hope after diagram, you will completely learn the 3 pin socket wiring, now if you have any question then do ask me.