SOFT STARTER

WE WELCOME YOU ALLTHIS GROUP CONSISITS OF1) THAKKAR DHARA C.-1202201090032) PATEL CHINTANKUMAR M.-1202201090273) CHAUDHARI PAYAL K.-1202201090484) LAXMI SINGH-120220109062

Topics to be discussed in next 10 mins:- How does it looks like? Defination Working principle In side delta circuit Selection between Soft starter or VFD DSP based soft starter Comparison Benefits Applications

How does it look like

Defination

It is a device used with AC electrical motors to temporarily reduce load and torque in the power train by reducing current and voltage.

Function of Induction Motor To Accelerate itself and its load to full speed To maintain the load at full speed efficiently and Effectively

over the full range of loading

Electrical Effect The electrical impact of large starting current can be serve enough to

cause. Large voltage dips Supply voltage Drops :- Affect entire Operation Baring of Switching contacts Increased line losses Risk of Exceeding maximum demand

What is the requirement of starter

IT IS DUE TO THE EXTREME LIMITS CAUSED IN A MOTOR. Start/stop motor without considerable effect on other Apparatus.

Working

How does soft starter work ? An algorithm controlling three pairs of back to back SCRs are used to

start and stop the motor. The back to back orientation of the SCRs allows the ac voltage to be

controlled by changing the firing angle every half cycle. Voltage is limited to provided current limit starts.

In Side Delta Circuit in Soft Starter The standard connection of the

electronic starter is used is 3 wire. An alternative connection is 6 wire or inside delta connection.

In-line soft starter all three phase are directly connected in series with device. Like overload relay and contactor

In side delta circuit soft starter, Connected device (SCR) are inside delta Circuit But do not have To be in line With Starter.

Benefits of In-side Delta Circuit Major Advantage is The

current in SCR 58% than it would be for the same motor connected in 3 wire.

Possible reduction in size of starter required

Cost reduction Reduced motor Cable size

Selection Between Soft Starter and Variable Frequency Drive

According to:-1) Application(Speed in running Condition)2) Function provision3) Efficiency4) Heating effect at starting and running condition5) Harmonic Content6) Physical Size7) Maintenances8) Cost

Digital signal processing Based Soft StarterNecessity:- Load Failure or improve starting torque, Motor Start with full load PRINCIPLE:- Control Variable voltage and Variable frequency

DSP BASED SOFT STARTER BY SIEMENS

Three Basic methods for starting fixed speed 3 phase

motor 1) Full Voltage Starting [DOL]2) Specific Reduced Voltage Starting [Star-delta starter]3) Variable Reduced Voltage Starting [Soft starter]4) Part Winding starting [Auto Transformer]

Comparison

Benefits Soft start and soft stop Reduced current peaks Avoidance of line voltage fluctuations during start-up Reduced load on the power supply system Reduced mechanical load in the drive Considerable space savings Reduced wiring compared to other starters Maintenance free switching Ease of handling Perfectly matched with SIRIUS devices for the control cabinet

Applications In Pump applications – a soft start can avoid pressure surges. In Conveyor belt systems – smooth start avoids jerk and stress on drive

components. Fans or other systems with belt drives – start slowly to avoid belt slipping. In electrical R/C helicopters – soft start allows the rotor blades to spool-up

in smooth and controlled manner. In all systems- limits the inrush current and so improves stability of the

power supply and reduces transient voltage drops that may affect other loads.