Technology

Musical Reeds to measure RPM

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This old tachometer uses music box type reeds to measure motor RPM without electricity. It's more useful than a digital Tach because it shows you resonant frequencies and can be used to check hammer and reciprocal speeds too.

This is a pretty neat device, after watching this video this weekend. They still make them but they are enormously expensive due to the limited demand and the cost of manufacture.

Technology Connections – Fans; High is next to Off on purpose

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I've been woefully uneducated about the different types of electric motors and this got me reading and thinking about the different versions of this technology and how IGBTs and microprocessors using variable frequency drives have really changed things over the years.

Car computer

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Technically any four stroke gasoline engine is a mechanical computer as its has a cam shaft that drives valves that are timed to do a specific program of opening and closing at controlled times.

All computers run programs – mechanical computers use cam shafts while electronic computers use programs stored in some form of electronic memory. Outside of internal combustion engines, cam shafts are increasingly rare and even inside of modern cars cam shafts don’t really exist in the traditional way.