745900-12 — DC Rotary Actuator Repair & Overhaul

Component Overview

A DC rotary actuator converts electrical power into rotary motion to position a load through a defined angular travel, serving within the aircraft actuation system as a motorized actuator for moving panels, valves, or control surfaces. It typically integrates a DC motor, a reduction gear train, and an output drive, often with limit switches or a position feedback element to define end stops. In service it drives mechanisms requiring repeatable, controlled rotation. Common degradation modes include brush and commutator wear, winding insulation breakdown, gear-tooth wear and backlash, bearing spalling, and contamination or corrosion of internal contacts. Limit-switch maladjustment, output-shaft seal leakage, and loss of holding torque also drive overhaul, with electrical continuity and torque-versus-travel checks confirming serviceability.

Aircraft Application

Part number 745900-12 (DC Rotary Actuator) is installed on the Bombardier Dash 8. QTC supports operators and MROs servicing this platform with certified repair and overhaul.

Our Repair Capability

QTC repairs and overhauls 745900-12 to the original manufacturer's specifications under our FAA and EASA Part 145 approvals. Our team — including former OEM actuation engineers — performs teardown, inspection, cleaning, component replacement, functional testing, and certification, returning a serviceable unit with the appropriate airworthiness release. We also develop repairs for rejected and beyond-economic-repair (BER) hardware.

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Related Parts

Other dc rotary actuator part numbers we repair — view all DC Rotary Actuator parts →

Frequently Asked Questions