What is the maximum electrical power the PTCU can provide continuously and intermittently?

• A. 200 A continuously, 250 A intermittently
• B. 250 A continuously, 300 A intermittently
• C. 150 A continuously, 200 A intermittently
• D. 100 A continuously, 150 A intermittently

Answer: (A)

Power delivery from the PTCU is limited by what the unit can safely dissipate thermally. It’s designed to provide a steady current that it can sustain indefinitely, and a higher current for short bursts when cooling allows. Specifically, the PTCU is rated to supply 200 A continuously and 250 A for intermittent periods. If your aircraft DC system runs at about 28 V, that translates to roughly 5.6 kW continuous and about 7 kW during brief surges. This arrangement lets you handle transient high-demand loads without overheating, while protecting the unit during longer operation. The other options would either push beyond the continuous thermal capability or fail to support necessary short-term peaks.