Power supply
Power supply is an important consideration for underwater video operations and
particular attention should be paid to the stability of the voltage and frequency.
Video cameras actually have low power requirements and work on 12 or fewer
volts. An uninterruptible power supply (UPS – stabilised power supply) system is
advisable where possible if only to power the surface recorder. For the underwater
system, if the loading is too high for a UPS system, then a separate power supply
is advisable. At sea, loading on a shared generator will vary with the ship’s
requirements and the mere act of turning on a cooker or heating system can cause
on-screen and recording interference. Voltage irregularities may be smoothed in
transformation, but frequency alterations have greater effects on recorders.
High voltages and currents are often encountered in underwater systems and
extreme care should be taken to ensure that the system is correctly maintained,
protected and earthed. Attention is drawn to the UK association of diving contractors
code of practice for electricity underwater (AODC, 1985) or any other national
security rules.