Changeover Swiych
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Transcript of Changeover Swiych
Load transfer switches
by
Saman RajapaksaAssistant manager-technical training
ROTAX LTD
Classification of load transfer switches a) type of construction
b) type of transition
c) type of source
d) type of application
e) compliance with different international standard publications
Type of construction
a) knife blade type
b) magnetic contactor type (IEC 60947-4-1)
c) circuit breaker type (IEC 60947-2)
d) power contactor type (IEC 60947-3)
e) static type (IEC 62310)
Type of construction
Knife blade type
Non load breaking Manually operated Slow switching transfer process No arc chutes Limited life span Cheaper in cost
Magnetic contactor type
Electrically held contacts Drop out on loss of control voltage Mechanically interlocked Possibility to close both contactors together Not a true double throw device Padlocking not possible Manual operation not possible Low short circuit fault current rating
Circuit breaker type Protection/switching
combined changeover device
comprises multi components
Slow transfer speed due to motor operator
Designed for short circuit making/breaking capabilities
Side by side or superposed mounting
Not a true double throw device
Power contactor type
Extremely High short circuit making capabilities Compact unit with less auxiliaries Inherent mechanical interlock due to double throw
device One ordering code for the complete unit
Static type
Two live sources required Extremely fast switching transition in less than ¼
cycle Silicon controlled rectifier technology Used for critical loads with two reliable/ independent
power sources High cost discourages standby applications
Type of Transition
type of source
Type of Application
Manual load transfer switch
Semi automatic load transfer switch
Fully automatic load transfer switch
Manual load transfer switch
Independent manual operation
Front/side (left/right) operating positions
Standard /delayed transition options
Complies with IEC 60947-3 standard
Semi automatic load transfer switch
Remote transfer switch equipment (RTSE) receiving external commands for switching
Motor/solenoid operation
Manual operation possible
Complies with IEC 60947-3 standard
Fully automatic load transfer switch
Comprises of a motorized load transfer switch with inbuilt controller
Programmable control /operating sequence Sensing of supply voltage/frequency of
mains/generator Complies with IEC 60947-6-1 standard
Compliance with standards
IEC 60947 - low voltage switch gear and control gear
Part 2 - circuit breakers Part 3 - switches, disconnecters, Part 4-1 – electromechanical contactors Part 6-1 - automatic transfer switch
equipment IEC 62310 - static transfer switches
IEC 60947-6-1
Formulated for ATSE equipment Classifies ATSE as class PC and class
CB Class PC – capable of making /withstanding
but not intended for breaking short circuit currents
Class CB -capable of making/breaking short circuit currents with over current releases
Utilization categories (continued)
IEC 60947-3 utilization categories
AC-20A/AC-20B- connect/disconnect under no load conditions
AC-21A/AC-21B-switching resistive loads AC-22A/AC-22B-switching mixed
resistive/inductive loads AC23-A/AC-23B –switching motor/highly
inductive loads
Utilization categories (continued)
IEC 60947-6-1 utilization categories
AC -31A/AC-31B - non inductive loads AC- 33A/AC-33B -mixed motor/resistive
loads AC-35A/ AC-35B –electric discharge lamp
loads AC-36A/ AC-36B- incandescent lamp loads
Salient features of ATSE equipment
Customer assembled switching units (circuit breakers/contactors etc) will not comply with IEC60947-6-1
Factory assembled switching units tested as per the standard by independent testing authorities ( eg; KEMA) comply with IEC 60947-6-1
Salient features of ATSE equipment (continued)
THANK YOU