Category Archive for: «Low Voltage»

Page 1 of 512345»

Rating Definitions Applied to Low Voltage Molded-Case Circuit Breaker (MCCB)

For system protection 600V and below The molded-case circuit breaker is the “workhorse” for system protection 600V and below. A circuit breaker is a device designed to open and close by nonautomatic means and to open the circuit automatically on a predetermined overcurrent without damage to itself when properly applied within its rating. The following terms apply […]

Read More

Methods Of Securing LV Circuit Breakers

Methods Circuit breakers are typically secured in place by one of the following methods: Through bolts Bolted to the bus Stab locked to the bus or some type of receptacle connection Din rail mounted Bolted Type Breakers When a longer service life breaker is wanted, a bolted type is typically used. These types have a […]

Read More

Methods Of Mounting LV Circuit Breakers

Three general groups Methods used to mount circuit breakers can be divided into three general groups, those being: Fixed Removable (disconnectable unit), and Drawout (withdrawable) A review of these mounting methods follows. Fixed Mounted Circuit Breakers A circuit breaker that is bolted in its enclosure and wired to the load frame, we can call a […]

Read More

10 Important Precautions When Working On Low Voltage Energized Equipment

Have eyes in the back of head… For most work, the electrical equipment must be de-energized because there is a high risk of injury to workers if they work on energized equipment. It may be possible to schedule such work outside of normal work hours to limit the inconvenience. Sometimes it is not practicable to completely disconnect low-voltage […]

Read More

Harmonic Distortion and High Frequency Applications

Distortion of the fundamental sine wave The presence of harmonic frequencies in addition to the fundamental 50Hz, bring about distortion of the fundamental sine wave. Considerable problems may arise dependant upon the level of this distortion. Sources of harmonic distortion can be: Variable Speed Drives UPS equipment Non linear load (switch mode power supplies) Special […]

Read More

What affects the operating temperature within LV switchgear

Maximum ambient condition BS EN 60439 states a maximum indoor ambient temperature of 40ºC, a maximum daily average of 35ºC and a minimum ambient of -5ºC. As a general guidance rule, the temperature within the low voltage switchgear should not exceed 50/55ºC. If Switchroom/Plant room ambients are typically considered to be up to 25°C this […]

Read More

Example of MV/LV network structure with dual fed main MV switchboard

Connected to article: Example of standard MV/LV network structure Network structure: MV consumer substation; The main MV switchboard can be backed up by a generator set and it feeds two MV/LV transformers; MV switchboard can be GIS or AIS and consist of following cubicles: – two incoming feeders (from utility) – two transformer cubicles – […]

Read More

Switching contactor and effect of long control lines

Voltage drop In accordance with IEC 60947-4-1 and IEC 60947-5-1, the normal control voltage range of power and control contactors lies between 85 … 110 % of the rated control voltage. Within these limits contactors pull-in perfectly. Frequently contactors are offered with an extended control voltage range, thus for example with contactors with electronic coil […]

Read More

Using AC switchgear in DC applications

Skin effect Switchgear designed for alternating current can carry at least the same rated continuous operational DC current. With direct current the skin effect in the circuits disappears and none of the specific effects associated with alternating currents such as hysteresis or eddy current losses occur. DC devices that are operated at low voltage can be […]

Read More

Defining Size and Location of Capacitor in Electrical System (2)

Continued from part 1: Defining Size and Location of Capacitor in Electrical System (2) Content Size of circuit breaker (CB), fuse and conductor of capacitor bank: A. Thermal and magnetic setting of a circuit breaker B. Fuse selection C. Size of conductor for capacitor connections Size of capacitor for transformer no-load compensation: Fixed compensation Sizing […]

Read More
Page 1 of 512345»


FOLLOW EEP!

Subscribe to Weekly Download Updates: (free electrical software, spreadsheets and EE guides)

Advertisement

EEP's Android Application
Electrical Engineering Daily Dose
Daily dose of knowledge and news from
Electrical Engineering World