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0 pointsmark-r8y ago0 comments

In an ideal world with infinite competition and perfect knowledge about competing products, perhaps you'd be right. But in the real world where we live, it happens all the time.

Start by reading about the Phoebus cartel: https://spectrum.ieee.org/tech-history/dawn-of-electronics/t...

I remember my first electric razor. It failed after a couple of years, so I took it apart to find out why. I discovered that the electrical contacts to the motor were just little pieces of graphite, and when they wore down to nothing the razor was finished. Definitely planned obsolescence in action!

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kqr8y ago

Are you saying there are reasonably priced long-lasting equivalents to graphite brushes? I'm asking out of ignorance. Because that would be really good to know when buying any appliance that has a rotating part. My impression is that they all use graphite brushes.

userbinator8y ago

Large appliances like washers and dryers use brushless motors, although the newer ones are likely to be inverter/VFD-based instead of the older induction type, where the control electronics will fail long before the motor itself wears out (bearings etc.)

(Search YouTube for "vintage induction motor" and you'll find plenty of century-old(!) examples still in good running condition. I don't think the same can be said of the brushless motors today.)

mark-rOP8y ago

There must be, certainly there are no graphite brushes in your spinning hard disk. That might not have been a common motor design back when I had that razor though, but they certainly could have used a beefier piece of graphite.

clort8y ago

hard disks have brushless motors

  https://en.wikipedia.org/wiki/Brushless_DC_electric_motor

they are usually more expensive but have been around for a long time.

AFAIK there is no substitute for graphite in a brushed motor, it is needing to transfer power to different sections of a rotating part in turn and does so by rubbing over a set of copper strips. That the graphite is soft is why it works well but also why it wears out rather than the commutator, which will survive several sets of brushes.

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