🔌 Star-Delta Starter Component Calculator

Star-Delta Component Master

Unit Type Kilowatts (kW) Horsepower (HP)

Motor Rating

System Voltage (V)

Safety Factor

Motor FLC0.0 A

Main Contactor0.0 A

Delta Contactor0.0 A

Star Contactor0.0 A

Overload Relay (OLR)0.0 A

Star-Delta Selection Logic & Formulas

Bhai, 5HP se badi motor ke liye hum Star-Delta starter use karte hain taaki starting current ko 1/3 tak giraya ja sake. Chalo ek-ek component ka formula samajhte hain.

1. Full Load Current (FLC) Formula

Motor kitna current legi, ye is formula se nikalta hai:

FLC (Amps) = (kW x 1000) / (1.732 x V x PF x Eff)

Note: PF (Power Factor) aur Efficiency (Eff) hamesha 0.85 ke aas-paas mani jati hai.

2. Contactor Selection (Main, Delta & Star)

Log galti yahan karte hain ki teeno contactor ek hi size ke laga dete hain, par calculation alag hoti hai:

Component	Asli Formula	Kyun?
Main Contactor	FLC x 0.58	Ye Phase current handle karta hai.
Delta Contactor	FLC x 0.58	Run mode mein load is par hota hai.
Star Contactor	FLC x 0.33	Star mein current 1/3 ho jata hai.

3. Overload Relay (OLR) Set-Point

Relay ki setting motor ke FLC par nahi, balki Phase current par honi chahiye:

Relay Setting = Full Load Current (FLC) x 0.58

Example: Agar motor ka FLC 10 Amps hai, toh relay ko 5.8 Amps par set karein.

4. Timer Setting aur Pairing

Bhai, timer hamesha **5-10 second** ke beech rakhein. Sabse ahem hai Delta pairing:

• Hamesha U1-V2, V1-W2, W1-U2 ka combination rakhein.
• Galat pairing se motor Delta mein switch hote hi trip ho jayegi.

Engineer Tip: Hamesha AC-3 duty rating wale contactors hi select karein, warna contactor ke point jaldi jal jayenge!