Thursday, December 19, 2013
Monday, December 9, 2013
Circuit breaker accessories - Service releases
Shunt opening release
This allows circuit-breaker opening by
means of an electric command. Release
operation is guaranteed for a voltage
between 70% and 110% of the rated
power supply voltage Un, both in AC and
in DC. It is always fitted with an auxiliary
limit contact.
Under voltage release
This opens the circuit-breaker due to a
power supply failure to the release, or
voltage drops to minimum values of 0.7
x Un with a trip range from 0.7 to 0.35 x Un.
After tripping, the circuit-breaker can be
closed again, starting with a voltage
higher than 0.85 x Un. With the undervoltage
release de-energised, neither
circuit-breaker nor main contact closure
is possible.
Time-delayed undervoltage release
The undervoltage release can be combined
with an external electronic power
supply time-delay device, which allows
circuit-breaker opening to be delayed in
the case of a power cut to the release
itself, according to fixed time-delays of
0.5-1-2-3 [s], so as to avoid unwarranted
trips caused by temporary malfunctions.
It is available for the SACE S3, S4, S5,
S6, and S7 circuit-breakers with power
supply voltages at 110-220 V (50-60 Hz)
only coupled with an undervoltage release
at 310 V DC.
Shunt closing release
This allows circuit-breaker closure by
means of an electric command. Operation
of the release is guaranteed for a
voltage between 80% and 110% of the
rated power supply voltage Un, both in
AC and in DC.
ABB SASE
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.
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