PPRuNe Forums - Electric Brakes

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I have read in many publications recently about the advent of electric braking. Boeing have opted this as a default on the 787 with Goodrich and Messier Bugatti as suppliers. As far as I know there is no hydraulic contingency so they must be serious.

Having done a bit of research, there appears to be a few benefits but also a big pile of troubles and woes. The concept is simple (see http://www.messier-bugatti.com/IMG/pdf/frein_en.pdf) and plug and play option is a great idea (saves us bleeding the brakes after installation).A smattering more of built in test and dispatchability with one of the electric motors inop are where it looks appealing.

However, to get the torque to the brakes, we are talking some serious voltage. How does 270V DC sound to a mechanic standing in a puddle next to a wet landing gear with highly conductive brake dust spread over the truck? Surely this is a major health and safety risk overlooked by Boeing?? Equally, to get the power to the electric motors you will need some serious wiring - resolvers, power, parking systems in each motor all need to be individually wired which must be a massive weight disadvantage over a single hydraulic pipe.

Anyway, does anyone else see an advantage to these machines? Any ground engineers concerned about being zapped???!!:confused:

Mechs are used to dealing with lots of high voltage/current systems. It doesn't really matter the location of the system as the standard of modern connectorss are very effective at keeping moisture and contamination where they should be.
As for the high voltage systems, if standard AMM precautions are followed then there is no hazard when maintaining the systems!:\

Quote:

Originally Posted by birdofprey (Post 2976857)

However, to get the torque to the brakes, we are talking some serious voltage. How does 270V DC sound to a mechanic standing in a puddle next to a wet landing gear with highly conductive brake dust spread over the truck? Surely this is a major health and safety risk overlooked by Boeing?? Equally, to get the power to the electric motors you will need some serious wiring - resolvers, power, parking systems in each motor all need to be individually wired which must be a massive weight disadvantage over a single hydraulic pipe.
Anyway, does anyone else see an advantage to these machines? Any ground engineers concerned about being zapped???!!

Interesting subject, those brakes. Perhaps the weight advantage is a result of the system savings taken as a whole. I can see advantages in weight, reliability, and maintenance costs.

Plenty of high voltage at the wheels already:
Brake Fans, Anti-Skid actutators, gear truck pivots, APU control boxes and landing lights. All very safe, rain or shine. :ok:

As I understand it the brakes are powered only when actually in dynamic use, and when not required (parking brake on, or off to roll/park) they are driven to the required position, braked (the drive motors braked, that is) and depowered.