Automatic Star Delta Starter using Relays and Adjustable Electronic Timer for Induction Motor
The project is designed to provide low voltage start to induction motors. This is achieved by using star to delta conversion. Star/Delta starters are probably the most common reduced voltage starters in the 50Hz industrial motor world. Star delta is used in an attempt to reduce the start current applied to the motor. Thereafter, full load current is applied to the motor.
The Star/Delta starter is generally manufactured from three contactors; and electromechanical timer and a thermal overload for operating a 3 phase motor at 440 volt at ac mains supply 50 Hz. The interlocking arrangement of all the contactor coils is traditionally wired in 440 volt AC.
This project uses a system to start a 3 phase motor at 440 volt AC mains supply 50 Hz with a set of 12 volt DC relays in star mode first and then to delta mode by an electronically adjustable timer. A set of relays are used to shift the motor connections from star to delta with a time delay.
The project is supplied with six lamps instead of a 3 phase motor i.e., two lamps representing each phase winding of the motor. The interlocking arrangement of the relay coils and the electronic timer are all wired in low voltage DC of 12 volt fed from an inbuilt DC power supply for safe handling of the starter during the study. It still retains its application for a 3 phase motor starting with single phasing prevention also.
During star operation the lamps would glow dim indicating the supply voltage across the coils are 440/root of (3). In delta condition after the timer operates the lamps would glow with full intensity indicating full supply voltage of 440volts. The timer comprises of a 555 in mono-stable mode the output of which is fed to a relay for changing the mains supply from 3 phase star to delta.
The project also has the provision of single phasing protection since 3 phase motors get burnt if any one phase goes missing during running. The output to the lamps shall be completely cut-off in the event of any phase failure.
Further the project can be enhanced by using a thyristors in firing angle control principle for soft start of the induction motor that would overcome all the drawbacks of star delta starter.
- Easy to use, Self-explanatory kit.
- All-inclusive solution kit.
- Extensive audio-visuals available.
- Branding-free material.
- Non-Microcontroller Project.
- Low Cost Relay Star-Delta Starter.
- Call/mail for Tech Support from 10 am - 7 pm.
- Can be Customized for Arduino, Raspberry Pi, PIC
- 3CO Relays
- 1CO Relay
- 555 Timers
"I live in Hyderabad, a place that is known for engineering colleges. Went with frnd and bought a set from Ameerpet(tht hs rdymade stuff like this) and it failed just b4 viva. Thats when we got this thx to a senior who is sorta like a geek.. and let me tell u.. Its one reason why me and my frnds got thru the final sem. Works great and is useful too later.. "Ravi Teja
Order No: HYF1290
"A must-buy. It helped me practice in real time and learn how to make a project by looking at an actual workable unit. (fyi - you get a fully built unit and another full set of components to build another by yourself) so it was great value for us. We shared the costs by 3 (our team for the project) but i got to keep my unit as the other two kept the original. Showed it for my on-campus and got thru too becuase it not just looked neat and profesionally bt worked great later. (still have it in my room, now working with GE in Bangalore) "Anusha
Order No: BLR2933
"We have used it for our institution - it is available in lab and has been good for explaining various models in live during class. Strongly suggest every college dept to have it for labs as it is working well - even with regular use at lab for more than 1 year. Note:We got the unit complementarity before launch in 2014 and have later purchased few batches. The team behind it is professional and know what electronics students need and i am writing this review on their request on 13/05/2016"Mr. Ramesh Kumar Jha
Order No: BQF3698
Q: What is automatic star-delta starting?
A: Automatic star delta starting means to switch on a 3 phase load in star connection for a set time and then automatically changing over to delta connection.
Q: Why is the star-delta starter needed?
A: The star delta starter is needed to extend the life of the motorand protect itfrom drawing high current at the start
Q: What is the rating of motor to be used in this project?
A: 3 phase, ¼- ½ HP motor rating is used in this project.
Q: Is single phasing protection available?
A: Yes, single phasing protection is available.
Q: What is the three phase induction motor rating to be used?
A: Three phase induction motor can be used, but limited up to 1 HP only as it uses a relay of 6A contact rating only. For higher HP just use a contactor of appropriate rating. The 230 AC coil of the contactor is powered in series from one of the contacts of the relay.
Q: What is the formula for calculating smoothing capacitor value?
A: There is some approximated formula .Peak to peak ripple voltage = Load current in amps / (2*line frequency in hertz *capacitance in farads). But as rule of thumb for 1 A current 1000uF is best. Thus it is load dependent.
Q: What to do when the lamp fails and what is the maximum lamp rating that can be used?
A: If the lamp fails one can use any lamp or bulb which is used in homes up to 100W. We suggest you to go for low watt bulbs.