VSR(vibratory stress relief equipment) maintenance-relieving residual stress

VSR(vibratory stress relief equipment) maintenance-relieving residual stress
How to determine motor line No.3 No.4 No.5?
No.3 No.4 No.5 motor line should be soldered when change a new motor tachometer board. 
But how to distinguish? 
The NO.3, 4, 5 line is drawn from the motor head air outlet.
So carefully observe the pin identification in the aviation socket, 
at the same time, measure the three lines with a multimeter to identify them.

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