USCG PSC Equals meaningful Polar Presence
The Coast Guard needs a ship that can do more than just break ice; it needs a multi-mission ship to provide for the nation’s security, asserting its sovereign rights, and protecting its long-term economic interests. That ship is the Polar Security Cutter.Since Russia cashed the check in 1867 for the purchase of Alaska the U.S. has been an Arctic nation. Today, it is one of eight countries that have…
Catastrophic Equipment Failures of VFD and HF Systems
Commercial and military users of electric propulsion systems have experienced failures of the variable frequency drive (VFD) and harmonic filter (HF) systems because the system design, including the VFD, did not have adequate self-monitoring and protection. On a ship, a variable-frequency drive (VFD) can be used to control the speed and direction of rotational motors, such as pumps, propellers and azipod systems.