Starting System
Left Ground Fault Transformer (UZ005)

Location - The transformer is located inside the aft power junction box in the tailcone.  Open Access panel  311AZ  and remove the aft junction box cover to access the transformer.

View of aft power junction box 

1.  Left Ground Fault Transformer (UZ005)
2.  Right Ground Fault Transformer (UZ004)

Operation - The left ground fault transformer is used to detect a short circuit to airframe ground in the Left Starter/Generator (SG1) positive feeder cable.  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.