September 2015
A platform to learn electrical wiring, single phase, 3 phase wiring, controlling, HVAC, electrical installation, electrical diagrams.
As refrigerator mechanic," mostly people ask me that her refrigerator not cooling and they take me to his/her home to check refrigerators, There are some main reason and problems of fridge and freezer not working and in this post i am writing about refrigerator not cooling problems and it's solution.

8 Refrigerator not Cooling Problems And It's Solution / Repair


refrigerator not cooling

Test the electrical outlet

Mostly refrigerator stop working and stop cooling due to outlets where we get supply for refrigerator. In simple words every one know that refrigerator works on electric energy and if electric supply is not receiving to the fridge then how can it work. In this problem when we try to start the refrigerator and Ref not starting. The short and simple way to test the outlet voltage, plug in refrigerator shoe  and then check the lamp of refrigerator.
If the lamp is glowing then there is no internal problem in electrical outlet and if its not glowing then test the outlet incoming current using multimeter or other electrical testing devices. You can also test the outlet / socket by plugging in other electrical substance e.g example plug in you mobile charger and see what happen, if your mobile get charging it's means that your outlet is right and have not internal problem.
Also read
How to wire electrical outlets?
How to test voltage using multimeter

Refrigerator is start but not cooling

In some countries the incoming voltage is too low or we can said that low voltage is also a reason or refrigerator not cooling or not working of a refrigerator. In many Cases- refrigerator compressor is start up and then trip. It's means that the incoming voltage is low for refrigerator compressor motor Or other problem in compressor or PTC relay.
Note that the 220 volts compressor not working on 110 - 115 volts supply. If your refrigerator compressor required 220 volts supply and your incoming supply is only 110, then use a step up transformer or a voltage regulator to step up voltage.

Check the thermostat switch


We use the thermostat switch in refrigerator to make an open electric circuit or automatic switch off compressor motor when refrigerator compressor complete his cooling. We use the thermostat switch in series between the compressor and electric supply. Mostly children switch off compressor supply form thermostat switch and we think there is a problem in refrigerator or the it's stop cooling well . Test your thermostat switch do it correct.

Check the PTC Relay and overload Protector


Test your PTC relay and overload protector and if you seen any problem in these devices then change it, if you can not do it himself then call a professional.
Also read
What is Overload Protector and How it works
How a PTC relay Works in refrigerators compressor

Check the supply wire of Refrigerator


If your refrigerator wire have internal damages or open circuit, then this also a big reason of refrigerator not cooling.

Compressor Problem

Check the compressor using ohm meter and find out the problem and if your compressor is burn  or have internal winding problem then change the compressor. Also test the shortage of compressor between compressor terminal and compressor body using connectivity test. The compressor not working is also a Problem of refrigerator not cooling
Also read
How to test identify the compressor terminals

Refrigerant / Gas leak problem

If your refrigerator compressor start properly and it's not cooling. For that problem first of all start the refrigerator and test the condenser pipe which is connected with compressor Hi pressure point if the compressor is start and this pipe is not getting heat then it's means that your refrigerator have no refrigerant gas, and have a leak problem.
A platform to learn electrical wiring, single phase, 3 phase wiring, controlling, HVAC, electrical installation, electrical diagrams.
This post is all about the fuse box and importance in electrical wiring. In this post we will discus the electrical fuse boxes and it's working and properties in electrical wiring. INSHALLAH our next post will about the fuses box wiring diagram. But in this post we will only lighting about the importance of fuses.

What is Fuse Box?

Fuse is electrical safety device which we use in electrical circuit to protect our electrical appliances from damages and burn. In simple words a fuse in an electrical low resistance device which protect the electrical devices form over current or to protect electrical wiring in case of short circuit.
A fuse box is an electrical panel box where we wired all fuse for protection. Are we can said the circuit point where the fuses in connected between supply and circuit.
Note That a fuse will always contact in series between supply and load.
We can also called circuit breaker box a type of F box, because the circuit breaker is also protection devices which we wire for safety in electrical wiring.

fuse boxes


How A fuse Works?

A fuse is low resistance electrical device which cut off the electric current flow in case of high or over current flowing. E.g example if a fuse is design for 5 ampere (A) load and the circuit start getting high current (ampere). When current will increase  form the 5 ampere the resistance will heat of due to high current flow and due to heat the fuse burn and make an open circuit.
A platform to learn electrical wiring, single phase, 3 phase wiring, controlling, HVAC, electrical installation, electrical diagrams.
We know that for power wiring / 3 phase motor wiring we use mostly the magnetic contactor or motor starter. In this post we will study the magnetic contactor importance, working / function and it's uses in electrical technology. I also share post about M contactor wiring diagram but this post specially for function and working of 3 phase contactor or motor starter.

What is Magnetic Contactor?

We can also said that a contactor is type of electrical relay which we use for power electric motor to start or stop. Contactor make easy to controlled 3 phase induction motors. We know that 3 phase motor required three phase supply to run, 3 phase supply is two dangerous which we can not handle with a circuit breakers for induction motor. Contactor make easy to handle the 3 phase motor controlling. The parts of the magnetic contactor are coil, iron core, 3 contacts points and NC, NO points.

magnetic contactor
Contactors

How a Magnetic contacor Works

The function of a contactor or motor starter is simple, when the AC supply goes to the contactor coil, the coil make a strong magnetic field and field pulls the iron core to the coil and make a electrical contacts.
A platform to learn electrical wiring, single phase, 3 phase wiring, controlling, HVAC, electrical installation, electrical diagrams.
Last time i wrote a post about normally open switch and this post is about the normally close switch or NC switch. A NC or normal close switch is a switch which have close electric circuit in normal state. Or we can said that normal close push button switch is switch which is close electric contact in normal state and when we push it then switch make a open contact or open circuit.
A platform to learn electrical wiring, single phase, 3 phase wiring, controlling, HVAC, electrical installation, electrical diagrams.
I published 2 post about power wiring / 3 phase wiring and in both post i talked about normally open switch and i used it in my diagrams. There will be many peoples how  don't know about that what is a normally open switch or what is NO push button switch and how its works.
To make these question off, i am gonna to write this post and i  disuse only normally open switch in this post which we better known with his short name NO which mean normal open switch . However my next post will be about the Normally close switch or NC push button.

What is Normally open switch and How it's works

This switch is momentary switch which is internally open electric circuit in normal state just like doorbell switch or we can said that doorbell switch is a good example of normal open switch. When ever we push this switch, it make contact of electric supply or make a close electric circuit. We can also called normally open contact switch.
There are some images of normal open push button switch and it's symbol for better understanding.

normally open switch symbol
Normal open push button switches and symbol

Uses of Normally open switch / NO push button switch


A platform to learn electrical wiring, single phase, 3 phase wiring, controlling, HVAC, electrical installation, electrical diagrams.
For three phase motor we always wire contactor, this post help you in contactor wiring and i hope after this post you will be able to wire a 3 phase motor, i also published a post about 3 phase motor wiring with magnetic contactor and thermal overload relay, but today post and contactor wiring diagram is too simple and easy to learn. 2 days ago i wired 380 to 440 volts contactor for a 3 phase motor and save these images of contactor in PC. Its is important to share with you these images but you can not learn clearly with out a diagram.



How To Wire a Contactor With Overload relay


thermal overload relay with contactor


In the above image i wire a contactor and thermal overload relay for a three phase motor, with NC and NO push button.
Note that NC means Normal Close and NO means  Normal Open, in clear words NC push button is a button which is normally close circuit and NO push button is a button which is normally open electric circuit.

NC push button we use for switching off the motor and NO push button for Switching On the electric circuit or 3 phase motor.

Normal close and Normal Open push button
Contactor buttons


I know these images help you very mush in contactor wiring or contactor instillation but you can not learn completely with out a diagram. So in below contactor wiring diagram i shown a contactor with a thearmal overlaod relay, 3 phase motor and NC, NO push button switches with complete wiring method.

contactor wiring diagram
Power wiring diagram

In the above diagram i shown complete method of contactor wiring and 3 phase motor wiring and wiring installation method. Note that always connect the earth wire to the electric motor body. In the above contactor wiring diagram i did not shown any type of step down transformer or neutral wire for magnetic contactor coil because i use a 440 volts contactor in above circuit diagram, however you can learn some more from below links.

Also Read.
How to Wire a 3 Phase Motor With Contactor and Overload Relay.


Message:

I hope you learn some thing from this post and now you will be able to wire a contactor for 3 phase motor, however i will soon write about more power wiring diagram.