modern version of a turbo-electric drive system. The IPS is a dual system, with each half consisting of a gas turbine prime mover directly coupled to an electrical generator, providing power for an electric motor that drives a propeller shaft. The system is "integrated" because the turbo-generators provide electrical power for all ship systems, not just the drive motors. The system provides much more available electrical power than is available in other types of ships. The DDX proposed using permanent-magnet motors (PMMs) within the hull, which was abandoned in favor of a more conventional induction motor. An alternate twin pod arrangement was rejected as the ramifications of pod drives would require too much development and validation cost to the vessel. The PMM was considered to be another technology leap and was the cause of some concern (along with the radar system) from Congress. As part of the design phase, Northrop Grumman had the world's largest permanent magnet motor designed and fabricated by DRS Technologies. This proposal was dropped when the PMM motor failed to demonstrate that it was ready to be installed in time. Zumwalt has Converteam's Advanced Induction Motors (AIM) rather than DRS Technologies' Permanent Magnet-Synchronous Motors (PMM). The exact choice of engine systems remains somewhat controversial at this point. The concept was originally for an integrated power system (IPS) based on in-hull permanent magnet synchronous motors (PMMs), with Advanced Induction Motors (AIM) as a possible backup solution. The design was shifted to the AIM system in February 2005 in order to meet scheduled milestones; PMM technical issues were subsequently fixed, but the program has moved on. The downside is that AIM technology has a heavier motor, requires more space, requires a "separate controller" to be developed to meet noise requirements, and produces one-third the amount of voltage. On the other hand, these very differences will force time and cost penalties from design and construction changes if the program wishes to "design AIM out" … The system reduces the ship's thermal and sound signature. As noted by the GAO, the IPS has added to weight growth in the Zumwalt-class destroyer. Electric power is provided by two Rolls-Royce MT30 gas turbines (35.4 MW ea.) driving Curtiss-Wright electric generators. The second ship of the class, Michael Monsoor, will require a new gas turbine after she experienced problems during sea trials resulting in damaged turbine blades. Automation and fire protection Automation reduces