Electrical Red Seal Formulas

Electrical calculations become easier when you can identify the relationship before reaching for a calculator. The electrical Red Seal formula library organizes common study formulas such as Ohm's Law, power, three-phase relationships, transformers, voltage drop, and motor-related calculations with variable definitions and worked examples.

Calculation practice can involve choosing the right relationship, keeping units consistent, deciding whether a Code-book value must be looked up, and checking whether the result is reasonable.

• Ohm's Law: V = I × R, I = V / R, R = V / I.
• Power Formulas: P = V × I, P = I² × R, and P = V² / R.
• Three-Phase Power: P = √3 × V × I × PF and S = √3 × V × I.
• Transformer Calculations: Turns ratio, voltage ratio, current ratio, and impedance.
• Motor Calculations: Full-load current, conductor sizing, and overload-protection study methods.
• Voltage Drop: Single-phase and three-phase voltage-drop relationships and percent-drop checks.