What is auto transformer starter?
This starter produces high efficiencyand have the option to be adjusted to obtain the necessary torque and in accordance with the system.It very efficiency stater but the disadvantage is it very high cost to setup control panel stater.
It can improved torque ratio is achieved and
starting current is typically 3 timesFull Load Current , depending on the voltage taps
selected.Typically it have taps at 50%,65% and 80% voltage.
During start-up, the motor is connected to the auto transformer’s tapping. This means that themotor starts up with a reduced voltage and a
correspondingly low curren
Operating principles
The technique for connecting an Auto Transformer stater is via magnetic contactor and connect the motor to taps by mean of the contactor.When motor accelerate to full speed,the tap of contactor was open and disconnecting motor from transformer and other contactor close to connecting the motor to the supply.
When the motor has almost reached its rated torque, the star
connection on the transformer is opened.
The transformer’s partial windings act as
chokes in series to the motor windings, and therefore, like the uninterrupted star
delta connection,
the motor speed does not drop during switch over.
After the main contactor has been switched in, the motor
windings are applied to the full mains voltage.
Finally, the transformer is disconnected from the mains circuitAccessories for MCCB
As we know,Molded Case Circuit Breaker main function is
protection device from overload current and short circuit.It also have a several
attachment device for additional protection that we can combine with MCCB.
Common accessories used for MCCB such as phase insulation barrier,Shunt
trip,Under voltage trip device,rotary handle and change over system.It can
provide more protection .
Types of Molded Case Circuit Breaker
MCCB
Before we make a decision to install Molded case circuit
breaker for our application,firstly we need to know about types of MCCB.It important
information that we must know to make sure our MCCB can functioning properly to
protect our application from electrical failure. As we know the main function
of MCCB are to protect our system .
MCCB protection for induction motor
Circuit breaker is a one of important protection device when
installing of electrical induction motor.This time i want shared some
information about the major parameter that we need consider when applying
Molded case circuit breaker(MCCB) for electric motor. If we not selected the
right MCCB for our electric motor application,it will effected to the system.
Vacuum circuit breaker
What is Vacuum circuit breaker? As we know vacuum mean the
the pressure is maintained below atmospheric pressure( unit : mmHg ).So the
manufacture made a research and development to design the vacuum circuit
breaker based on current cannot jump in vacuum condition. This breaker used the
vacuum pressured to extinguish the current .
Circuit breaker specific features for main switchboard
Circuit breaker specification for MSB. For circuit breakers
specification MUST suitable with installation condition and needed.Main
switchboard is the main power supply distribution for factory or building.This
unit is a key for entire electrical power supply distribution. It feed the high
volume of voltage for all equipment and machine.
Maintenance for low voltage circuit breakers
Low circuit breaker normally operating at 600 volt AC and
below.The common used types of circuit breaker around the world such as
molded case circuit breaker (MCCB) and Air circuit breaker ( ACB ). This low
voltage circuit breaker usually used for power distribution and sub power
distribution at factory and general industry.
Routine maintenace tests for circuit breaker
Routine maintenance tests Circuit breaker is the important
protection device for our application and electrical power supply system.It can
save our equipment or machinery from damage from over current or overload
matter.It also can save personal life who involve directly or indirectly with
electrical application from electric shock. How we can know the actual
condition .
Molded case circuit breaker maintenance
Important of circuit breaker maintenance The circuit breaker
maintenance is very important and it must added in periodical maintenance
schedule.Why it so important?It is because of their importance for routine
switching and for equipment protection and person. Production will stop if
circuit breaker fails to operate because of a lack of preventive
maintenance.
Miniature Circuit Breaker Sizing
When we design or build a electrical installation,we must
know how to choose the suitable circuit breaker for the any application that we
design.For electrician,this is compulsory knowledge.So here i want share my
little knowledge about circuit breaker sizing method. This calculation for
sizing the miniature circuit breaker.For other circuit breaker likes
MCCB,ACB,VCB,OCB and etc,
Residual Current Circuit Breaker
What is Residual current circuit breaker ( RCCB )? This
device is very important in electrical wiring.It is a life guard device to
protect from electric shock.Others circuit breaker only can detect the fault
from over current and short circuit but cannot detect the current leakage. That
why RCCB is very important.
Molded Case Circuit Breaker
What is MCCB ( Molded Case Circuit Breaker ) ? It is a
mechanical device ( BS 4752 ) to be used to connect and disconnect the circuit in
normal and abnormal.Current rate for regular MCCB up to 3000 ampere.It is only
available in a 3 pole only .
Miniature Circuit Breaker
MCB (Miniature Circuit Breaker ( BS 3871 ) is a mechanical
device operate automatic operation designed to connect and disconnect the
electrical circuit in the ordinary and extraordinary situation.Suitable for AC
and DC voltage.It mean main function is to protected equipment or circuit from
overload and short circuit. The size of MCB is small .
Fuses
What is a FUSE? Fuse is a basic device used to break the
circuit when there is a overcurrent.it consists of metal wire fuse element
which is connected by two terminal.fuse element will be blow if the current
through it exceeds the limit was set. Its use is widespread due to the
efficiency and durability.
Protective Device Introduction
Electrical distribution systems are often quite complicated.
They cannot be absolutely fail-safe. Circuits are subject to destructive
overcurrents. Harsh environments, general deterioration, accidental damage or
damage from natural causes, excessive expansion or overloading of the
electrical distribution system are factors which contribute to the occurrence
of such overcurrent.
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