Starting System
Left Ground Fault Transformer (UT005)

Location - The transformer is located on the upper left portion of the first frame aft of the aft pressure bulkhead.  Airframe Ground GT001 is located outboard of the transformer

View looking outboard at left transformer

1.  Left Ground Fault Transformer (UT005)
2.  Airframe Ground GT001

Operation - The left ground fault transformer is used to detect a short circuit to airframe ground in the Left Starter/Generator (SG1) negative terminal.  The ground fault sensing circuit is active during generator operation and disabled during engine start by the Left Start PC Board (NZ011).  If a ground fault occurs while the generator is operating, the Left Generator Control Unit (BT001) de-energizes the the left generator relay to isolate the starter/generator from the bussing system. 

NOTE: The measured resistance between terminals X1 and X2 on the current transformer is approximately 4.6 ohms.