RCU Forums - View Single Post - Hot Hot Motor!
Thread: Hot Hot Motor!
View Single Post
Old 10-26-2018, 04:21 PM
  #4  
ron_van_sommeren
 
ron_van_sommeren's Avatar
 
Join Date: Sep 2002
Location: Nijmegen / Nederland
Posts: 628
Likes: 0
Received 22 Likes on 17 Posts
Default
  • Overheating magnets causes de-magnetizing (irreversible! ), which in turn results in higher Kv. Motorcurrent is proportional to Kv³ , and resistance losses in the copperwire are proportional to current². Therefore resistance losses are proportional to Kv⁶!!!
  • Hotter motor → weaker magnets → higher Kv → higher current → hotter motor → weaker magnets → higher Kv → higher current ⟲⟲⟲ etcetera etcetera, temperature runaway, major conflagration
  • Several motor tests
    1. Determining whether magnets still have original strength, by determining whether Kv motor parameter (in rpm/volt) is still the same, several simple straightforward methods.
      www.bavaria-direct.co.za → motor constants
    2. Generator test, only using a power drill and a voltmeter
      (Re)winding and building motors - RCG (sticky) → opening post → #40 Generator test
    3. Drytesting brushless motors - WFF (RCG user vollrathd)
    4. Opening an outrunner for visual inspection

    Prettig weekend Ron
ron_van_sommeren is offline  
Reply Like