3-phase formula mein root 3 kyun aata hai?

3-phase mein current 120 degree apart flow karta hai. Resultant vector calculation mein 1.732 aata hai. Single phase mein 2 conductors mein drop add hoti hai isliye factor 2 hai.

Electrical Calculator — No. 06

Voltage Drop
Calculator

Q: Voltage drop zyada hone se kya hota hai motor ko?

Motor ko rated voltage se kam milta hai, torque kam hoti hai, motor zyada current kheenchta hai, overheating aur winding burn ka risk badh jaata hai.

Q: Copper vs Aluminium Gulf sites pe kya use hota hai?

Final distribution ke liye Copper mandatory hai. Aluminium large HV feeders mein. Aluminium ki resistivity 1.6x zyada hoti hai.

Q: Gulf interview mein voltage drop pe kya poochha jaata hai?

Formula, IEC limits, practical calculation examples, aur drop kam karne ke tarike.

Q: Voltage drop kam karne ke kya tarike hain?

Cable size badhao, cable length kam karo (DB paas rakho), voltage level badhao, ya parallel cables use karo.

3-Phase aur Single Phase — Copper aur Aluminium cable. IEC standard ke hisaab se Pass/Fail result. Gulf sites ke liye must-have tool.

Calculator

Voltage Drop Nikalo

Saari values daalo — drop volts mein, percentage mein, aur Pass/Fail IEC standard ke saath milega.

Phase Type

System Voltage (V)

415V Gulf/India 3-phase | 230V single phase

Valid voltage > 0

Load Current (A)

Full load current of the circuit

Valid current > 0

Cable Length (m)

One-way length (source to load)

Valid length > 0

Cable Size

Material

Load Type (IEC limit)

IEC 60364-5-52 standard limits

Results — IEC 60364 Standard

Voltage Drop

—V

Drop in Volts

Drop Percentage

—%

Limit: —%

Receiving Voltage

—V

At load end

Cable Resistance

—mΩ

Total loop resistance

Drop vs IEC Limit

0%10%

Theory + Site Knowledge

Voltage Drop — Kya Hota Hai?

Bhai, Gulf ki har badi site pe — Qatar University ho, Sidra Hospital ho ya koi industrial plant — ek common problem hai: cable itni lambi hai ki load tak pahunchte pahunchte voltage gir jaata hai. Isko hi Voltage Drop kehte hain.

Main Mohammad Arif hoon, 12+ saal ka experience hai. Maine dekha hai Qatar University site pe 200 meter ki cable pe motor chalna band ho gayi — kyunki voltage drop 8% se zyada tha aur motor ko enough voltage nahi mil rahi thi. Agar yeh calculator tab hota, 2 ghante ki investigation 2 minute mein hoti.

Formula — 3-Phase aur Single Phase

3-Phase: VD = √3 × I × R × L / 1000
1-Phase: VD = 2 × I × R × L / 1000

R = resistivity / cross-section (mΩ/m)
VD% = (VD / V_supply) × 100

IEC 60364 Limits — Gulf Standard

KAHRAMAA Qatar aur DEWA UAE dono IEC 60364 follow karte hain. Yeh limits mandatory hain:

Load Type	Max Drop	Gulf Sites
Lighting	3%	Emergency lights, office lighting
Power / Motor	5%	AC units, pumps, motors
Sub-distribution	8%	Distribution boards to sub-DBs

Resistivity Values (at 70°C)

Material	Resistivity	Use
Copper	0.0183 Ωmm²/m	Standard Gulf wiring
Aluminium	0.0296 Ωmm²/m	Large feeders, overhead

Qatar University Site — Real Example

Problem: 50A motor, 415V 3-phase, 120m cable, 25mm² Copper

R = 0.0183 / 25 = 0.000732 Ω/m

VD = 1.732 × 50 × 0.000732 × 120 = 7.61V

VD% = 7.61 / 415 × 100 = 1.83% → PASS ✓ (limit 5%)

Receiving Voltage = 415 – 7.61 = 407.4V — Motor ke liye safe

⚠ Cable size sirf current ke hisaab se mat chuno! Lambi cables mein voltage drop limit karne ke liye cable ek size upar lena padta hai. Cable heating post mein yeh detail se explain hai.

Frequently Asked Questions

Voltage drop zyada hone se kya hota hai motor ko? +

Bhai, motor ko rated voltage se kam milta hai to torque kam hoti hai. Motor zyada current kheenchta hai apni speed maintain karne ke liye — isliye overheating hoti hai, winding burn hone ka risk badh jaata hai. Long term mein motor ki life kam ho jaati hai. Isliye motors ke liye 5% limit set hai IEC mein — is se zyada drop hone par cable size badhao.

3-phase formula mein √3 kyun aata hai? +

3-phase system mein teen conductors hain aur current teeno phase mein 120° apart flow karta hai. Resultant voltage vector calculation mein √3 (1.732) aata hai — yeh basic vector mathematics hai. Single phase mein sirf ek hot aur ek neutral hota hai, isliye return path ke liye factor 2 lagta hai (do wires mein drop add hoti hai). Yeh Electricity basics mein bhi explain hai.

Copper vs Aluminium — Gulf sites pe kya use hota hai? +

Sidra Hospital, Qatar University jaise projects pe final distribution ke liye Copper mandatory hoti hai — better conductivity, less voltage drop, reliable connections. Aluminium mainly HV overhead lines aur large feeder cables (185mm² aur upar) mein use hoti hai kyunki weight aur cost kam hoti hai. Aluminium ki resistivity copper se 1.6x zyada hai — isliye same current ke liye bada size chahiye. Cable heating guide mein yeh detail mein hai.

Gulf interview mein voltage drop pe kya poochha jaata hai? +

Common questions: “Voltage drop formula batao”, “IEC ke hisaab se maximum drop kitni honi chahiye?”, “Ek 50A motor 100 meter door hai, 35mm² copper cable pe drop kitni hogi?”, “Drop kam karne ke tarike kya hain?”. Gulf interview complete guide mein in sabka ready-made jawab hai.

Voltage drop kam karne ke kya tarike hain? +

Teeen main tarike hain. Pehla — cable ka cross-section badhao (size upgrade karo). Doosra — cable ki length kam karo — DB ko load ke paas rakho. Teesra — voltage level badhao (jahan possible ho). Kuch cases mein parallel cables bhi chalte hain. Gulf projects mein yeh DB placement at design stage decide hota hai — isliye DB design stage pe yeh calculation karna zaruri hai.