Generator GN38  
Used in EE8, BD71/2, RM29A etc.  
This is the remains of an EE8A that we learned magneto theory on in A&P school. The GN38 and MC131 were mounted at opposite ends of a board. They were wired direct so the bell rang when you cranked the generator. I reassembled the parts and the result is the complete bottom half of the phone. 
GN38 is a handcrank magneto generator. It is used to create ringer current in field phones. GN38 (From TM11330 pg23) Crank Gear Ratio = 15 Output Frequency at 1000 rpm of armature (200 rpm of crank) = 16 cycles Output current at above speed: 200 ohm res = 90 milliamps 1000 ohm res = 50 milliamps 10,000 ohm res = 9.5 milliamps Open circuit voltage (approximate = 100 volts) 
GN38 variations  
All 3 have the same gears.  
GN38A has a different switch (because of stationary coils.) 

GN38 compared to GN41  
GN41 is used in EE91. GN41 appears to be a 4 magnet version of a GN38. GN41 coil is longer and most likely has more current capability. 

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