Automatic Star Delta Starter Using Relays And Adjustable Electronic Timer For Induction Motor

Automatic Star Delta Starter using Relays and Adjustable Electronic Timer for Induction Motor

Automatic Star Delta Starter using Relays and Adjustable Electronic Timer for Induction Motor Introduction:  Induction motors are popular due to their low-cost, sturdy construction, fast pick-up, low maintenance expenditure and real efficiency.  The DOL (direct-on-line) starters and star/delta starters used for starting and running of induction motors provide coarse type of protections against voltage fluctuations and single phasing.  Induction motors are very sensitive to low voltage and single phasing during which they draw a heavy current and can burn out unless switched of within few seconds of occurrence of such conditions

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Automatic Star Delta Starter using Relays and Adjustable Electronic Timer for Induction Motor

 An Induction or asynchronous motor is a type of AC motor where power is supplied to the rotor by means of electromagnetic induction, rather than a commutator or slip rings as in other types of motor  These motors are widely used in industrial drives, particularly poly -phase induction motors because they are rugged and have no brushes.  Their speed is determined by the frequency of the supply current, so they are most widely used in constant-speed applications, although variable speed versions, using variable frequency drives are becoming more common.

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Automatic Star Delta Starter using Relays and Adjustable Electronic Timer for Induction Motor Block Diagram:

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Automatic Star Delta Starter using Relays and Adjustable Electronic Timer for Induction Motor Hardware Requirements:         

Power Supply Block Relay Induction Motor 555 Timer Bc 547 Transistor Bc 558 In4007 Rectifier Diode Led RESISTORS And CAPACITORS

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Automatic Star Delta Starter using Relays and Adjustable Electronic Timer for Induction Motor 555 TIMER:  The 555 Timer IC is an integrated circuit (chip) implementing a variety of timer and multivibrator applications.  The original name was the SE555 (metal can)/NE555 (plastic DIP), and the part was described as "The IC Time Machine".  Depending on the manufacturer, the standard 555 package includes over 20 transistors, two diodes, and 15 resistors on a silicon chip installed in an 8-pin mini dual-in-line package (DIP-8).

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Automatic Star Delta Starter using Relays and Adjustable Electronic Timer for Induction Motor Pin Diagram Of 555: The 555 timer IC is a mere eight pin DIL package IC. It can be  Used as a monostable.  Source or sink 100mA.  Use supply voltages of 5v to 15v.  Disrupt the power supply - use a decoupling capacitor.

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Automatic Star Delta Starter using Relays and Adjustable Electronic Timer for Induction Motor Stator and Rotor:  The stator winding consists of three different windings which overlap one another and are offset by an electrical angle of 120°.  Synchronous Speed (Ns) = 60; f/p.  Ns= Synchronous Speed/ minute;  F= frequency;  P=Pole pair Number; Rotor in induction machines with squirrel-cage rotors consists of a slotted cylindrical rotor core sheet package with aluminum bars which are joined at the front by rings to form a closed cage. http://www.edgefxkits.com/

Automatic Star Delta Starter using Relays and Adjustable Electronic Timer for Induction Motor

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Automatic Star Delta Starter using Relays and Adjustable Electronic Timer for Induction Motor BC547:  The BC547 transistor is an NPN Epitaxial Silicon Transistor.  The BC547 transistor is a general-purpose transistor in small plastic packages.  It is used in general-purpose switching and amplification BC847/BC547 Series 45 V, 100 mA NPN general purpose transistors.  Whenever the base is high, then current starts flowing through base and emitter and after that only current will pass from collector to emitter .

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Automatic Star Delta Starter using Relays and Adjustable Electronic Timer for Induction Motor

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Automatic Star Delta Starter using Relays and Adjustable Electronic Timer for Induction Motor BC558: ďƒ˜ The BC557 transistor is a PNP Epitaxial Silicon Transistor. ďƒ˜ The BC557 transistor is a general-purpose transistor in small plastic packages. It is used in general-purpose switching and amplification BC847/BC547 Series 45 V, 100 mA PNP general-purpose transistors.

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Automatic Star Delta Starter using Relays and Adjustable Electronic Timer for Induction Motor Relay:  It is an electromagnetic switch.  Used to control the electrical devices.  Copper Core Magnetic Flux plays a primary role here.

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Automatic Star Delta Starter using Relays and Adjustable Electronic Timer for Induction Motor Circuit Diagram:

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Automatic Star Delta Starter using Relays and Adjustable Electronic Timer for Induction Motor Circuit Explanation:  Star – Delta starter generally comprises of contactors and an adjustable timer to enable starting of the induction motor in star mode and then switch over to Delta Mode after the preset time so decided by the timer.  This uses three step-down transformers, the primary of which are connected in star mode while their secondary develop filtered dc after passing through respective bridge rectifiers and filter capacitors out of the three. Such dc derived one dc is used for a timer circuit built around a 555 timer wired in a stable mode but operating in monostable mode.  Two other dc supplies operate the two relays. These two are connected in series with the third relay coil. Mains of the three phases are connected to the third relay. http://www.edgefxkits.com/

Automatic Star Delta Starter using Relays and Adjustable Electronic Timer for Induction Motor  Fourth relay takes star to the delta conversion care.  The timer operates this fourth relay.  Single phasing meaning any one or two phases Y & B missing bring either relay – 1 or relay - 2 to off condition that results in the relay – 3 to switch Off.  At starting due to the connection of the fourth relay in star, the motor begins as star connection  After the time elapsed by the timer operates the fourth relay coil. The relay switches Delta mode. It also gives the indication in which mode the motor is running by LED. http://www.edgefxkits.com/

Automatic Star Delta Starter using Relays and Adjustable Electronic Timer for Induction Motor Future Scope:  Compared to the reduced voltage methods it is the simple and cheapest way of starting the motor.  But it takes significant inrush currents during the switching operation.  Further the project can be enhanced by using thermistors in firing angle control principle for soft start of the induction motor that would overcome all the drawbacks of star delta starte r.

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Automatic Star Delta Starter using Relays and Adjustable Electronic Timer for Induction Motor Conclusion:  An automatic over and under voltage protector system has been implemented using induction motor starter which is necessitated by the need to monitor the voltage supply to the equipment and appliances.

Consequently, protect them from the danger of being damaged due to voltage fluctuation.  This type of starting is used for low to medium voltage and light starting torque motors.  It is the cheapest way to reduce the starting current, and it is in the order of 3-4 times that in case of direct online starting of induction motor. http://www.edgefxkits.com/

Automatic Star Delta Starter using Relays and Adjustable Electronic Timer for Induction Motor

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