AUXILIARY FIELD 



INTERNAL FIELD 



Fig. A. 12 Sensor head Internal and Auxiliary 

 magnetic field 



As the rope is moved the part of it leaving A will have 

 remnant magnetism in it. This remnant magnetism will 

 cause Axix. field A to decrease and Internal field A to 

 increase. This change will take place over the first 

 2-3 feet of rope movement. A previously zeroed LMA 

 chart record will show this increase as in Fig. 4.13. 



A-37 



