Monday, December 9, 2013

Friday, November 29, 2013

IEC standards

IEC 60038 Standard voltages

IEC 60076-2 Power transformers - Temperature rise

IEC 60076-3 Power transformers - Insulation levels, dielectric tests and external clearances in air

IEC 60076-5 Power transformers - Ability to withstand short-circuit

IEC 60076-10 Power transformers - Determination of sound levels

IEC 60146 Semiconductor convertors - General requirements and line commutated convertors

IEC 60255 Electrical relays

IEC 60265-1 High-voltage switches - High-voltage switches for rated voltages above 1 kV and less than 52 kV

IEC 60269-1 Low-voltage fuses - General requirements

IEC 60269-2 Low-voltage fuses - Supplementary requirements for fuses for use by unskilled persons (fuses mainly for household and similar applications)

IEC 60282-1 High-voltage fuses - Current-limiting fuses

IEC 60287-1-1 Electric cables - Calculation of the current rating - Current rating equations (100% load factor) and calculation of losses - General

IEC 60364 Electrical installations of buildings

IEC 60364-1 Electrical installations of buildings - Fundamental principles

IEC 60364-4-41 Electrical installations of buildings - Protection for safety - Protection against electric shock

IEC 60364-4-42 Electrical installations of buildings - Protection for safety - Protection against thermal effects

IEC 60364-4-43 Electrical installations of buildings - Protection for safety - Protection against overcurrent

IEC 60364-4-44 Electrical installations of buildings - Protection for safety - Protection against electromagnetic and voltage disrurbance

IEC 60364-5-51 Electrical installations of buildings - Selection and erection of electrical equipment - Common rules

IEC 60364-5-52 Electrical installations of buildings - Selection and erection of electrical equipment - Wiring systems

IEC 60364-5-53 Electrical installations of buildings - Selection and erection of electrical equipment - Isolation, switching and control

IEC 60364-5-54 Electrical installations of buildings - Selection and erection of electrical equipment - Earthing arrangements

IEC 60364-5-55 Electrical installations of buildings - Selection and erection of electrical equipment - Other equipments

IEC 60364-6-61 Electrical installations of buildings - Verification and testing - Initial verification

IEC 60364-7-701 Electrical installations of buildings - Requirements for special installations or locations - Locations containing a bath tub or shower basin

IEC 60364-7-702 Electrical installations of buildings - Requirements for special installations or locations - Swimming pools and other basins

IEC 60364-7-703 Electrical installations of buildings - Requirements for special installations or locations - Locations containing sauna heaters

IEC 60364-7-704 Electrical installations of buildings - Requirements for special installations or locations - Construction and demolition site installations

IEC 60364-7-705 Electrical installations of buildings - Requirements for special installations or locations - Electrical installations of agricultural and horticultural premises

IEC 60364-7-706 Electrical installations of buildings - Requirements for special installations or locations - Restrictive conducting locations

IEC 60364-7-707 Electrical installations of buildings - Requirements for special installations or locations - Earthing requirements for the installation of data processing equipment

IEC 60364-7-708 Electrical installations of buildings - Requirements for special installations or locations - Electrical installations in caravan parks and caravans

IEC 60364-7-709 Electrical installations of buildings - Requirements for special installations or locations - Marinas and pleasure craft

IEC 60364-7-710 Electrical installations of buildings - Requirements for special installations or locations - Medical locations

IEC 60364-7-711 Electrical installations of buildings - Requirements for special installations or locations - Exhibitions, shows and stands

IEC 60364-7-712 Electrical installations of buildings - Requirements for special installations or locations - Solar photovoltaic (PV) power supply systems

IEC 60364-7-713 Electrical installations of buildings - Requirements for special installations or locations - Furniture

IEC 60364-7-714 Electrical installations of buildings - Requirements for special installations or locations - External lighting installations

IEC 60364-7-715 Electrical installations of buildings - Requirements for special installations or locations - Extra-low-voltage lighting installations

IEC 60364-7-717 Electrical installations of buildings - Requirements for special installations or locations - Mobile or transportable units

IEC 60364-7-740 Electrical installations of buildings - Requirements for special installations or locations - Temporary electrical installations for structures, amusement devices and booths at fairgrounds, amusement parks and circuses

IEC 60427 High-voltage alternating current circuit-breakers

IEC 60439-1 Low-voltage switchgear and controlgear assemblies - Type-tested and partially type-tested assemblies

IEC 60439-2 Low-voltage switchgear and controlgear assemblies - Particular requirements for busbar trunking systems (busways)

IEC 60439-3 Low-voltage switchgear and controlgear assemblies - Particular requirements for low-voltage switchgear and controlgear assemblies intended to

be installed in places where unskilled persons have access for their use - Distribution boards

IEC 60439-4 Low-voltage switchgear and controlgear assemblies - Particular requirements for assemblies for construction sites (ACS)

IEC 60446 Basic and safety principles for man-machine interface, marking and identification - Identification of conductors by colours or numerals

IEC 60439-5 Low-voltage switchgear and controlgear assemblies - Particular requirements for assemblies intended to be installed outdoors in public places - Cable distribution cabinets (CDCs)

IEC 60479-1 Effects of current on human beings and livestock - General aspects

IEC 60479-2 Effects of current on human beings and livestock - Special aspects

IEC 60479-3 Effects of current on human beings and livestock - Effects of currents passing through the body of livestock IEC 60529 Degrees of protection provided by enclosures (IP code)

IEC 60644 Spécification for high-voltage fuse-links for motor circuit applications

IEC 60664 Insulation coordination for equipment within low-voltage systems

IEC 60715 Dimensions of low-voltage switchgear and controlgear. Standardized mounting on rails for mechanical support of electrical devices in switchgear and controlgear installations.

IEC 60724 Short-circuit temperature limits of electric cables with rated voltages of 1 kV (Um = 1.2 kV) and 3 kV (Um = 3.6 kV)

IEC 60755 General requirements for residual current operated protective devices

IEC 60787 Application guide for the selection of fuse-links of high-voltage fuses for transformer circuit application

IEC 60831 Shunt power capacitors of the self-healing type for AC systems having a rated voltage up to and including 1000 V - General - Performance, testing and rating - Safety requirements - Guide for installation and operation

IEC 60947-1 Low-voltage switchgear and controlgear - General rules

IEC 60947-2 Low-voltage switchgear and controlgear - Circuit-breakers

IEC 60947-3 Low-voltage switchgear and controlgear - Switches, disconnectors, switch-disconnectors and fuse-combination units

IEC 60947-4-1 Low-voltage switchgear and controlgear - Contactors and motor-starters - Electromechanical contactors and motor-starters

IEC 60947-6-1 Low-voltage switchgear and controlgear - Multiple function equipment - Automatic transfer switching equipment

IEC 61000 Electromagnetic compatibility (EMC)

IEC 61140 Protection against electric shocks - common aspects for installation and equipment

IEC 61557-1 Electrical safety in low-voltage distribution systems up to 1000 V AC and 1500 V DC - Equipment for testing, measuring or monitoring of protective measures - General requirements

IEC 61557-8 Electrical safety in low-voltage distribution systems up to 1000 V AC and 1500 V DC - Equipment for testing, measuring or monitoring of protective measures

IEC 61557-9 Electrical safety in low-voltage distribution systems up to 1000 V AC and 1500 V DC - Equipment for insulation fault location in IT systems

IEC 61557-12 Electrical safety in low-voltage distribution systems up to 1000 V AC and 1500 V DC - Equipment for testing, measuring or monitoring of protective measures. Performance measuring and monitoring devices (PMD)

IEC 61558-2-6 Safety of power transformers, power supply units and similar - Particular requirements for safety isolating transformers for general use

IEC 62271-1 Common specifications for high-voltage switchgear and controlgear standards

IEC 62271-100 High-voltage switchgear and controlgear - High-voltage alternating-current circuit-breakers

IEC 62271-102 High-voltage switchgear and controlgear - Alternating current disconnectors and earthing switches

IEC 62271-105 High-voltage switchgear and controlgear - Alternating current switch-fuse combinations

IEC 62271-200 High-voltage switchgear and controlgear - Alternating current metal-enclosed switchgear and controlgear for rated voltages above 1 kV and up toand including 52 kV

IEC 62271-202 High-voltage/low voltage prefabricated substations

Thursday, November 28, 2013

A hipot tester

A hipot tester is an electronic device used to verify the electrical insulation in a device or other wired assembly that could subject someone to a shock if it failed. It generally consists of:

 

1.            A source of high voltage,

2.            A current meter,

3.            A switching matrix used to connect the high voltage source and the current meter to all of the contact points in a cable.

 

Hipot testers may also have a microcontroller and a display to automate the testing process and display the testing results.

A hipot tester can be very similar to a cable tester and often the two are combined into a single device.

In a typical wired assembly a hipot test should connect all circuits in common to ground. Then, one by one the tester will disconnect a given circuit from ground and connect that circuit to high voltage . The current that flows is monitored to verify that it is low enough.

 

MILLIVOLT DROP TEST

The millivolt drop test is generally associated with

testing for weld quality on the armature. It is the

best test for verifying armature weld quality.

The millivolt drop test is the ultimate electrical test

for detecting bad welds. Unfortunately, it is

difficult to make on armatures with large diameter

wire and nearly impossible to make on armatures

with small wires.

The difficulty is breaking through the insulation on

the wire as it exits the tang or commutator bar

contact. The one testing contact, usually a sharp

knife edged probe, from the KOM (Kelvin Ohm

Meter) can cut through small wires and destroy

the armature. Contact with the knife-edge probe

needs to be made on each bar. Since this is such

a difficult test to perform, it is only practical as a

laboratory test.

Various test methods have been developed over

the last twenty years that come close to making

this test. These tests make it possible to test

100% of the armatures. However, none of these

tests are as accurate or repeatable as the Millivolt

Drop Test.

ESW's weld test, which uses techniques that have

been developed over the past 20 years, comes

very close to the Millivolt Drop Test. The

repeatability and speed of the test using a

stationary armature test fixture assures that a

reliable test has been performed.

 

Thursday, October 24, 2013

Methods of explosion protection for electrical equipment

METHODS OF EXPLOSION PROTECTION

Method                                                                                               Type of Protection

Designed to prevent any means of ignition arising            Ex e Increased Safety

Ex n or Ex N Non Sparking

Designed to limit the ignition energy of the circuit            Ex I Intrinsic Safety

Designed to prevent the flammable mixture reaching    Ex m Encapsulation

a means of ignition                                                                          Ex p Pressurisation

Ex o Oil Immersion

Ex nR or Ex N Restricted Breathing

Designed to prevent any ignition from spreading              Ex d Flameproof Enclosure

Ex q Powder Filling

 

Friday, October 18, 2013

Minimum terminal capacity for copper protective conductors (PE, PEN)

CROSS-SECTIONAL AREA OF PHASE CONDUCTORS S
MM2
MINIMUM CROSS-SECTIONAL AREA OF THE CORRESPONDING PROTECTIVE CONDUCTOR (PE, PEN) SPA
MM2
S ≤ 16
S
16 < S ≤ 35
16
35 < S ≤ 400
S/2
400 < S ≤ 800
200
800 < S
S/4
a Current in the neutral may be influenced where there are significant harmonics in the load.
Minimum terminal capacity for copper protective conductors (PE, PEN)
Source: IEC 61439-1 2011 Table 5