High voltage circuit breaker

As we know about circuit breaker is to protect electrical equipment from abnormal condition such as over load current or short circuit.For Low voltage circuit breaker,i already explain on my last post.Please read my post about miniature circuit breaker (MCB),molded case circuit breaker (MCCB) and residual current circuit breaker (RCCB) for more detail information.

For high voltage circuit breaker,the main contact mechanism normally designed with various method to avoid from damage and provide a better quenching around the contacts surface.The main purpose is to extinguishing any arcs formed as faster as possible. read more

Star Delta Circuit Diagram

The most active post in Electrical Engineering Centre blog is Star delta starter and Star Delta motor connection.I received many comments and request for Star Delta circuit diagram.

So this time i want share my simple star delta circuit diagram completed with power and control line circuit.I hope it can be as basic reference for all electrician about star delta starter diagram.

Star delta starter is a common used in domestic and industry sector to drive variant application such as chiller water pump,machinery,air-compressor and many more equipment. read more

Fault protection

A new terminology for electrical currents now include all faults those between live conductors as well as earth or grounding faults.

If we not design our circuit protection properly followed standard guide,it can cause serious injury or death for human and equipment damage.

Fault current be determined at every relevant point. For small and medium installations with LV utility supplies, this is satisfied by determination of the fault currents at the incoming power supply. read more

Cooling method for transformer

Why cooling system for transformer very important? The amount of heat from a transformer typically dissipated  is about 12.5 watts per square meter of surface area per degree C.It also can prolong the transformer life span if it running in normal temperature without exceed the maximum limit.

Normally transformer installed in special area or room for power distribution such as sub station or power room.The heat generated from transformer must be removed by circulate the air by ventilation or by the cooling system.

Commonly manufacture use a method of lettering is used to denote the form of cooling for a particular transformer.Four upper case letters are used.The first pair of letters are for the heat removal from the windings and core. read more

How to replace bearings for electric induction motor?

For electric motor failure causes,the common defected for mechanical part is bearing.Normally 1 unit motor have a 2 pieces of bearing and type of bearing for induction motor is ball bearing full metal cover ( ZZ ).

Root cause for bearings problem usually such as rusty due to condensation process,ball in housing broken,grease was burn out,a ball bearing nest broken and overload or motor shaft connected with load is not alignment properly.

For electrician or maintenance person,this is a routine jobs and it is a compulsory skills for this person who involved in electrical motor field.

This time i want share my little experience how to replaced bearing for electric induction motor.Don’t worry, i explain detail step by step how it done in my video.I hope it can be a guideline  to do it yourself in actual workplaces. Read more


Relays have a wide range of application in industry.Even with the advent of electronic control such as PLC and other solid state devices such as thyristors,the electromechanical relay still retain a high level of acceptance.

We can found relay in every where such as control panel,equipment and machinery.It is common use for automation and motor control application.

The reason for this is that for simple types of control,relay offer a cost effective solution.They are available in a large range of configurations from small of only 10mm in length with multiple contact pair for data communication,to large relay called contactor for carrying heavy current loads in applications such as switching 3 phase motors. read more

Star delta motor connection

For star delta stater,the motor connection must have 6 cables from control panel and 6 terminals at induction motor ( U1,U2,V1,V2,W1,W3).To wiring the motor connection for star delta starter,the important thing that we must fully understand is about the basic of STAR DELTA MAGIC TRIANGLE.

For detail about star delta stater please read my last post about it. From this triangle diagram,we can determine the correct phase,cable termination for right terminal and the rotation.As we know,the star delta stater is so tricky if we not fully understand the concept and their method. This time i want share my technique when perform wiring task and connected to the star delta stater for induction motor.

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