How do I calculate motor capacitor size?

For a run capacitor: C ≈ P/(2π×f×V²×η×cosφ) × 10⁶ μF. A rough rule of thumb is 30-50 μF per HP for run capacitors and 100-150 μF per HP for start capacitors.

What is the difference between start and run capacitors?

Start capacitors are electrolytic, high-value (70-400 μF), used only during startup then disconnected by a centrifugal switch. Run capacitors are film type, lower value (5-60 μF), and remain in circuit continuously.

What happens if the capacitor is too small?

Too small: motor may not start (low starting torque), may overheat, reduced efficiency. Too large: excessive current in auxiliary winding, overheating, possible winding damage.

Can I use a higher voltage capacitor?

Yes, using a capacitor with a higher voltage rating is safe. However, never use a lower voltage rating than required — typically 1.5× the supply voltage for safety margin.

What are PSC and CSIR motors?

PSC (Permanent Split Capacitor) uses a run capacitor only — simple but lower starting torque. CSIR (Capacitor Start Induction Run) adds a start capacitor with centrifugal switch for higher starting torque, typical for compressors and pumps.

मुक्त अभियांत्रिकी साधन

मोटर कॅपॅसिटर कॅल्क्युलेटर

single-phase motors साठी स्टार्ट आणि रन कॅपॅसिटर मूल्ये मोजा. C = I / (2πfV). मोटर शक्ती, व्होल्टेज आणि वारंवारतेवर आधारित अंदाज.

स्टार्ट कॅपॅसिटररन कॅपॅसिटरसिंगल-फेज

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रन कॅपॅसिटर (अंदाजे)

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स्टार्ट कॅपॅसिटर (अंदाजे)

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मोटर प्रवाह

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किमान कॅपॅसिटर व्होल्टेज रेटिंग

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कॅपॅसिटर सूत्र

स्टार्ट कॅपॅसिटर सामान्यतः रन कॅपॅसिटर मूल्याच्या 3–5× असतात. रन कॅपॅसिटर film dielectric वापरतात; स्टार्ट कॅपॅसिटर electrolytic वापरतात.

Motor Capacitor Calculator — C = I/(2πfV) | Vibromera

Published by Nikolai Shelkovenko on फेब्रुवारी 15, 2026 एप्रिल 5, 2026

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