Examples In Electrical Calculations By Admiralty Pdf Site

Battery internal resistance (from Admiralty battery tables for that bank): ~0.02 Ω. Total resistance ~0.0856 Ω.

Checking the fuse’s time-current curve (Admiralty Handbook, Plate 12), a 40 A fuse would clear 1285 A in ~0.01 seconds — safe. But the mechanical switch arced badly. Gibbs recommended adding a high-speed circuit breaker. Post-war, HMS Vigilant got new radar. The induction motor load (radar rotating aerial) had a power factor of 0.65 lagging . Apparent power S = 8 kVA, true power P = 5.2 kW. The generator ran hot. examples in electrical calculations by admiralty pdf

The Admiralty tables listed nearest standard: copper cable. Installing that solved the tripping. Gibbs noted: “Always account for temperature rise — use 0.0204 Ω·mm²/m at 45°C for safety.” Example 2: Short-Circuit Calculation for a Searchlight A 3 kW searchlight (110 V) suddenly failed. A cable chafed against a bulkhead, causing a dead short. Gibbs needed to prove the protective fuse was correct. But the mechanical switch arced badly

Initial reactive power (Q_1 = \sqrt{S^2 - P^2} = \sqrt{8^2 - 5.2^2} \approx 6.08\ \text{kVAR}) The induction motor load (radar rotating aerial) had

Maximum allowable drop per core: 1.65 V (two cores in series).