Power factor capacitor installation

09/07/2011 by 3 Comments

Last time i already discuss about how to sizing the power factor capacitor.After we got a figure and corrected size for capacitor,the next step is what is types for installation of capacitor?

The installation of power factor capacitor have several method that commonly used around the world.This time i want share some information about types of power factor capacitor installation method.

This part is critical and important because if we wrong to choose the installation method,it can cause a damage for our equipment or machine.It also can effected all equipment in our placed. read more

Filed Under: Theory Tagged With: , , , , , ,

Electrostatic level and prevention action

05/07/2011 by Leave a Comment

Electrostatic level is a sudden electric current flow from one material to another material.If we remember how to generated electro static using rod plastic and cloth on science lab class.

Theoretically  a voltage level for ESD can damage for any electronic component is around 100-500 Volt.For the very sensitive electronic components,normally it only can withstand around 25-170 Volt.

How we can known the Electrostatic damage (ESD) phenomena?Normally we possibility can hear a ”click” sound when touching an object or equipment.From the research possibility voltage generate for the “click” sound is at least 3.5 kV. read more

Filed Under: Theory Tagged With: , , , , , ,

NEC calculation for overload sizing

01/07/2011 by 12 Comments

Sizing for overload is important to avoid serious damage for electrical application such as motor starter,machinery or others electrical equipment.

According to NEC,the general requirement for overload sizing be set around 115% or 125% from full load ampere.We should setting the overload relay within this parameter to avoid electric motor from serious damage.

For calculation of overload sizing,it depend on the motor full load ampere current rating,the service factor and temperature for motor.I already explain in my last post about several factor effected for overload relay sizing. read more

Filed Under: Motor Control Tagged With: , , , , , ,

Sizing for magnetic contactor

07/06/2011 by 12 Comments

When we design or replaced the magnetic contactor for motor starter or for others application,the important point is how to sizing the size of magnetic contactor.This is critical point because if we not sizing properly,it can cause a serious damage and our application maybe failure to perform in perfect condition.

This time i want  shared some information and basic technique how to sizing the magnetic contactor with properly method and suitable with our application needed.It is to ensure our application design is correctly function and have a good resulted. read more

Filed Under: Motor Control Tagged With: , , , , , ,

Low speed protection for A.C generator

29/03/2011 by 1 Comment

For a given excitation,if speed of an A.C. generator is reduced then the output voltage would reduce also.In practice,this reduction in output voltage is sensed by the AVR ( Automatic voltage regulator ) which increases the excitation current to compensate.

However,the field forcing capabilities of the AVR which are necessary to maintain output voltage during rapid load changes,will permit an “over-excitation” condition to exist.

As the regulator is not speed ( or frequency) sensitive,field forcing would occur damage field windings and rotating diode.In order to safeguard the machine against this condition,particularly where low speed duty or idling is anticipated a LSP ( low speed protection ) unit is available to sense prolonged over-excitation and automatically insert current limiting resistance in the field circuit. read more

Filed Under: Generator Tagged With: , , , , , ,

How to calculate electricity cost?

23/03/2011 by Leave a Comment

This part is important to us when suddenly our electricity cost is higher than normal usage.We can determine the figure from electrical supplier is correct or not

We also can calculated a electricity cost  for estimated our new electrical design such as install new motor,compressor,furnace or others equipment.With this calculation we can know the estimated of cost and can make a decision for that installation either it reasonable or not. read more

Filed Under: General Tagged With: , , , , , ,

Residual Current Circuit Breaker

23/01/2011 by 7 Comments

This device is important in electrical wiring installation.It is a life guard device to protect from electric shock.Others circuit breaker only can detect the fault from over current and short circuit but cannot detect the current leakage.

That why RCCB is very important.Only this device can detect the current leakage.The current leakage can cause the injury or dead for human and can lead to fire hazard.When design the distribution panel board,please make sure this device include in our planning to install..it for consumer safety and avoid equipment from damage. read more

Filed Under: Circuit Breaker Tagged With: , , , , , , , ,
« Previous Page
Next Page »