Showing posts from August, 2018


How ensure safe and risk free roof work?
Roof work is a high-risk activity because of involves working at height. Sometimes with fragile materials such as roof lights and asbestos cement roofing sheets etc. The good working plan can reduce the risk of any kind of hazardous work.
   Full edge protection at eaves level will normally be required for work on sloping roofs. The edge protection needs to be strong enough to withstand a person falling against it. The longer the slope and the steeper the pitch, the stronger the edge protection needs to be. A properly designed and installed independent scaffold platform at eaves level will usually be enough. Less substantial scaffolding barriers (rather than platforms) may not be strong enough for work on larger or steeper roofs, especially slopes in excess of 30°. Fragile Roof Surfaces:
Wherever possible make sure that all fragile materials 2m or closer to the people at risk are securely covered and a warning notice displayed. Alternatively, prov…


You may ask, where shell type and core type transformer are used and why? Simply we can say actually there is no any hard and fast rule to choose your core type or shell type transformer for a particular ranges area.

Mostly you will find some tendency to choose the core or shell type transformer used based on the practicalities; and it is a choice made by the designer.

The core transformer has one magnetic circuits; in this type transformer both the primary and the secondary windings are wound outside and surround the core ring means both windings are placed on the side limbs.
The shell transformer has one magnetic circuit; in this type transformer the primary and secondary winding pass inside the steel magnetic core which forms a shell around the winding.
In Practical core type transformer mainly uses in high voltage applications like electrical energy transmission, primary distribution, auto power transformer etc. The reasons are simple-
High voltage system deals high flux an…

Screw Type Air-Cooled and Water-Cooled Chiller Troubleshooting Manuals

Troubleshooting Manual for Air-Cooled and Water-Cooled Screw Chillers
To prevent screw type air-cooled and water-cooled chiller from potential damages there is now alternate way without preventive maintenance of equipment. You can reduce the unavoidable operation breakdown frequency, but may not bring-down a zero-level. 
During breakdown an equipment, you troubleshooter need specific manufacturer troubleshooting guide or manual.
This manual is for your screw type air-cooled and water-cooled chillers' controls sturt-up, operation, service and troubleshooting  manual that contains instruction for carrier screw chillers, 30GXN, R080-528; 30HXA, HXC076-271. 
The troubleshooting full 140 pages manual in pdf copy is available for download in link below:

Control start-Up, Operation, Service and Troubleshooting: Carrier
You may download the wiring schematic line diagram for air-cooled screw carrier chiller from link below:


How Does Condenser Fan Speed Controller Work?

What Is Condenser Fan?

A condenser fan in HVAC system is part of a heat pump or central air conditioning system that circulates air across the system's condenser coil to increase the transfer of heat. Generally you will find some condenser fan motors in sealed bearings, where others are lubrication system. In either case, though, fan functionality is vital.
If the condenser fan isn't working, the device fail to cool anything.In an air conditioning system, the condenser fan's role is really best explained by this simple fact.
To minimize the repairing hassle during breakdown, it's a good idea to check the fan motor to make sure the fan is still functioning preferably and less probability to go unwanted breakdown in early spring. 
To ensure that shut down the entire condensing unit at the electrical disconnect box and do a test setting the thermostat to cool, and then restore power. Observe and be sure the fan is turning and blowing a sufficient flow of air. If the device is…


Partial Discharge (PD) in Electrical Power Cable:

Why PD? No matter way where you are an engineer or a technician for electrical power cable, you need a pretty good knowledge about Partial Discharge or shortly PD to understand your cable life or the possibility of unwanted cable fault. You may gather knowledge about PD by watching video clips in YouTube or reading a blog or article about PD.

Introduction of Partial Discharge (PD):
Partial discharge (PD) is one of the most important factors for power cable system. The partial discharge measurement methods of assessing the quality of the insulation of power cable systems especially for extruded insulation materials.
Where Partial Discharge Occur: We can think partial discharge for cable system from two major points view:
01. Partial Discharge within the whole cable 02. Partial Discharge in an individual              location

Partial Discharge Measurement:

Normally major factory test carried out on the insulation of whole drum of extruded cable is…

How do you know if a transformer is step up or step down?

What is meant by step up and step down transformer?

We all are familiar with Transformer and its different types and uses; we may someone very much expert and working with transformer at our limited field or someone newer to introduce level. The fact is that sometime we face few critical problem in our working field. Today we will discuss and share our knowledge how we find the transformer is step-up or step-down when there is no identification marking.
"A transformer that increases voltage from primary to secondary is called a step-up transformer which is designed as more secondary winding turns than primary winding turns. Conversely, a transformer designed to do just the opposite is called a step-down transformer".
In very simply we can say a transformer can be used for both step-up and step-down. All that depends on the number of primary and secondary winding numbers. If we connect the primary side to AC supply mains and secondary side to some load, if the secondary has less…


What Is Transformer Oil? Transformer oil actually is Insulating oil which has excellent stable electrical insulation property at long time high temperature. Due to mass use this insulating oil in electrical oil-filled transformer, commonly it is called transformer oil. Not only transformer, it also uses in high-voltage capacitors, oil circuit reclosers, high-voltage switches & circuit breakers, florescent lamp ballast, etc..
Transformer Oil or Insulating Oil is also known as mineral insulating that normally obtained by fractional distillation and subsequent treatment of crude petroleum. Properties of Transformer OilBefore use any substances in electrical equipment, it’s physical, chemical and electrical properties should be known to get maximum efficiency using at safe condition. Main properties of Transformer oil is as below- It creates an acceptable level of insulation in combination with the insulating materials used in the conductors and coils; It also acts as a coolant to extract…

How Fix Blogger Not Found Error: Windows Live Writer

The latest Engineering, Science & Technology changing our life from smarter to the smartest everyday, even every moment. Today, lots of free apps and software are available with almost every stuff; but while writing a blog-post, the experience is not so easy enough. Especially for the guy who are not tech-expert like me, facing lots of stuck.
First time when I start writing a Blog, the text editing template was found very childish. Then I search for writing a Blog using MS Word directly, though I found lots of helping post, but works none for me.
I don’t know what is my fault, lack of my knowledge or my pirated MS Office. (Sorry, my software is pirated. Actually, here in Bangladesh except some corporate office, almost everyone use pirate software). I thought Blog not working for me due to this kind of piracy. Then I left the hope staying together with MS Word.
Latter on, I met with ‘Windows Live Writer’ but paid a lot because two step protected  g-mail account. Two step protected g-…

How Does VSD Work In Building HVAC System?

Download the quick reference full manual for installation wiring and troubleshooting:  VSD full manual🔻DOWNLOAD pdf (free)
AC Drive full manual🔻DOWNLOAD pdf (free)

What is VSD in HVAC System?VSD- a Variable Speed Drive in HVAC (Heating, Ventilating and Air-Conditioning) system is an important device that controls the electric motor speed. The variable speed drive (VSD) or variable frequency drive (VFD) also known as adjustable frequency drive (AFD), micro-drive, AC drive, inverter drive etc.
VSD attends to confirm the motor run at required specific speed as well as operates the motor at energyefficient way. The motor in heating, ventilating and air-conditioning (HACV) system massively used for regulated flow of water and air system where energy may save controlling motor speed rather constant speed. How VSD Ensure the Motor Fault Protection?Modern SSVSD or solid state variable speed drives have motor fault protection features and to ensure that VSD can monitors many parameters such as m…


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