Energy and Power
Which type of residual current device (RCD) to use and when?
We know how (very) important the total earth loop impedance Zs is in the reduction of shock risk. However, in TT systems where the mass of earth is part of the fault path, the maximum values of Zs given in… Read more
Apr 09, 2014 | By Edvard Csanyi
Energy and Power
Erection of earthing arrangements (TNC, TN-S, TNC-S, TT)
The earthing arrangements (TNC, TN-S, TNC-S, TT) of low voltage networks is largely determined by the Low Voltage Supplies. However, if the incoming supplies are at 11kV and the transformers are in the ownership of the user, the LV supplies… Read more
Apr 07, 2014 | By Edvard Csanyi
Testing and Commissioning
Inspection and Test procedures for Instrument Transformers
Visual and Mechanical Inspection Electrical Tests: Electrical Tests – Current Transformers Electrical Tests – Voltage Transformers Electrical Tests – Coupling-Capacitor Voltage Transformers Electrical Tests – High-Accuracy Instrument Transformers (Reserved) Test Values: Test Values: Visual and Mechanical Test Values: Current Transformers… Read more
Apr 04, 2014 | By Edvard Csanyi
Energy and Power
Electromagnetic stresses on a busbar system and methods of reducing
When a conductor carries a current it creates a magnetic field which interacts with any other magnetic field present to produce a force. When the currents flowing in two adjacent conductors are in the same direction the force is one… Read more
Apr 02, 2014 | By Edvard Csanyi
Energy and Power
Electrical Design Project of a Three Bed Room House (Part 2)
Continued from 1st part: Electrical Design Project of a Three Bed Room House (Part 1) All new domestic dwellings, including conversions, must either have: A fire detection and fire alarm system in accordance with the relevant recommendations of British Standard… Read more
Mar 31, 2014 | By Sufi Shah Hamid Jalali
Industrial Automation
PLC implementation of the bottle-filling application
In this example (see Figure 1), we will implement a control program that detects the position of a bottle via a limit switch, waits 0.5 seconds, and then fills the bottle until a photosensor detects a filled condition. After the… Read more
Mar 28, 2014 | By Edvard Csanyi
Energy and Power
Enclosure protection against ingress of solid objects and liquids
As you already probably know, IP stands for Ingress Protection. International Electrotechnical Commission – IEC 60529 “Degrees of protection provided by enclosures (IP Code).”. NEMA offers a similar rating system. In order to protect live parts of equipment being contacted… Read more
Mar 26, 2014 | By Edvard Csanyi
Cables
Underfloor cable systems explained in details
It should be understood that the generic term ‘underfloor’ applies to products designed for such use but which may well be used in other environments where the protection is appropriate. Ducts and risers, and within suspended ceilings are typical spaces… Read more
Mar 24, 2014 | By Edvard Csanyi
Energy and Power
Electrical Design Project of a Three Bed Room House (1)
Electrical design is not an easy task. It requires a lot of expertise. Detailed study is needed prior to installation work. The engineer must consider quality and any specific requirements together with price. Different options are to be examined. Choice… Read more
Mar 21, 2014 | By Sufi Shah Hamid Jalali
High Voltage
Hey Mom, look at that big HVDC Transformer!
HVDC transformers are key components of HVDC stations. HVDC converter and inverter stations terminate long-distance DC transmission lines or DC sea cables. This type of transformer provides the interface between AC grids and high power rectifiers and are used to… Read more
Mar 19, 2014 | By Edvard Csanyi
Industrial Automation
Let’s start learning the PLC programming
For managing and control of the electrical systems there once were used electromechanical relays. In time as technology advanced came and PLC devices (Programable Logics Controllers). Advantage of an PLC devices over relays is that they can be used for a… Read more
Mar 17, 2014 | By Vlada Markovic
Power Substation
How To Locate Current Transformers in HV Substation
Current transformers are used for protection, instrumentation, metering and control. It is only the first function that has any bearing on the location of the current transformer. Ideally the current transformers should be on the power source side of the circuit… Read more
Mar 14, 2014 | By Edvard Csanyi
Testing and Commissioning
Testing of power transformer – Measurement of impedance voltage and load loss
The measurement is carried out to determine the load-losses of the transformer and the impedanse voltage at rated frequency and rated current. On Figure 1 above (Circuit for the impedance and load-loss measurement) there are following figures: G1 – Supply… Read more
Mar 12, 2014 | By Edvard Csanyi
Energy and Power
Electrical Thumb Rules You MUST Follow (8)
Accuracy Class of Metering CT Accuracy Class Letter of CT Accuracy Class of Protection CT Continued from part 7: Electrical Thumb Rules You MUST Follow (Part 7) Metering Class CT Class Applications 0.1 To 0.2 Precision measurements 0.5 High grade… Read more
Mar 10, 2014 | By Jignesh Parmar
Electric Motor
Motor Starting via Chokes or Resistors
The series-connected chokes (Figure 1) or resistors (Figure 2) reduce the voltage at the motor and hence also the starting current. The starting torque is reduced by around the square of the current. At rest the motor impedance is small…. Read more
Mar 07, 2014 | By Edvard Csanyi
