Ironless Core DC Motors for Aerospace

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Blake Hopkins
5 years ago
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1 Ironless Core DC Motors for Aerospace

2 Market segments covered by AS/EN9100 Support equipment Space shuttle & re entry vehicles Aviation Commercial passenger aircraft Light aircraft Cabin equipment Science satellites UAVs Space Missiles Military aircraft Commercial satellites Navy Ground vehicles Defense Spy satellites Air launched anti satellite weapons

3 What options are available if you want a motor for aerospace applications? Go to a specialist engineering company and order a custom motor Very expensive Often no industrial heritage Order a catalog motor from a motor manufacturer Lower cost Motor may be completely unsuitable for application Customer needs to spend lots of effort testing

4 The middle option: COTS industrial motors modified for aerospace Industrial motors that have been modified to make them work reliably in extreme environments Intermediate price Potentially more reliable than custom motor due to industrial heritage. Application specific testing is an option (either at manufacturer internally or at external facilities, depending on requirements)

controllability Compact design superior volume/weight-performance ratio No magnetic

5 Why Ironless Core Motors High efficiency low power consumption Very low mass inertia highest acceleration Low inductance long life-time Linear characteristics good controllability Compact design superior volume/weight-performance ratio No magnetic cogging Low electromagnetic interference High reliability Iron Core Rotor Ironless Core Rotor

7 Mars Exploration Rover (MER) motors (Spirit & Opportunity) RE25+MR encoder (modified catalog product) RE20+MR encoder (customer specific development)

8 Mars Science Laboratory Motor with integrated brake for space mission Fully funded development project to rapidly complete new motor design Sample motors shortly afterwards

9 EC45 6-pole, Ø45 mm, 350W

16 Boeing 747 8I Powered Window Shades EC16max+GP16 (with thermal fuse)

17 Waste Disposal

18 Boeing Scan Eagle DC Motor as a Generator

19 UAVs & their payloads Pan & Tilt Mechanisms Gimbal Assemblies

20 UAV Flight control surfaces Motor+resolver+brake: EC40evo+RES26+AB44

21 Sentinal 3 Thruster Cut-off Valve

22 Solar Radiation and Climate Experiment (SOURCE)

23 Aerospace applications are different to standard industrial motors Can use industrial heritage but need to adapt: I. Vibration environment II. Wide temperature range III. Pressure (vacuum) IV. Long lifetime V. Must be reliably producible

24 What should be adapted on a standard motor? 1) Large temperature range causes different materials to expand/contract at a different rate. (May cause motor to fall apart!)

25 What should be adapted on a standard motor? 2) Standard lubrication in bearings and wiring insulation material are unlikely to be suitable at low temperatures 3) Motor may not be suitable for high or long term vibration environment. EC32HD bearing

materials are damaged by exposure to vacuum (i.e. Adhesives & some

26 Modifications for vacuum applications? For Space applications: Lubrication will outgas ( evaporate ) Many materials are damaged by exposure to vacuum (i.e. Adhesives & some plastics) Brush material won't last very long Worn standard RE13 brush RE13 brush material selected for ExoMars

27 What should be adapted on a standard gearbox? Large temperature range causes different materials to expand/contract at a different rate. 1) Change materials to allow all stainless construction 2) Weld planetary gear pins 3) Adhesive free 4) MIL spec grease Standard GP22 Modified GP22

How do we adapt our standard process to high reliability aerospace projects? Motor manufacturing for customer specific projects is an intrinsically manual process.

28 How do we adapt our standard process to high reliability aerospace projects? Motor manufacturing for customer specific projects is an intrinsically manual process. Following philosophy is being implemented: Apply GUID code to motor (and critical parts and subassemblies) and then track and document production Where possible store process data against motor ID Use automatic inspection to check work: Soldering quality Force controlled presses Laser welding Process control via computer ATP for each motor is documented automatically

29 Production Process Management For each motor (combination) there is a defined test sequence The data from each test are stored against the motor ID Only motors which have successfully completed all the defined tests are laser marked Every test station can be integrated into the process A test report can be provided automatically for each batch

30 Currently Implemented Run out measurement Dielectric strength testing (including automatic sequence) Resistance check (of winding or additional components) Encoder end test Motor/gearbox combination testing Final acceptance test station

31 Previous highlight space missions Pathfinder (Sojourner rover) motors Mars Exploration Rovers 2003 (Spirit & Opportunity) 39 motors Phoenix lander (2008) 11 motors

32 Thank You

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