The global success of  modules is a result of the simplification of all vital electronics for 
the AC and DC functions of the system to a single circuit board. 
All modules of each type are interchangeable and identical for rapid replacement. The 
modules are hard-wired to eliminate loose connections caused by vibration. Each module 
is subject to rigorous testing to eliminate any defective components. Modules are calibrated 
at the factory and require no adjustments in the field. Service and troubleshooting of the 
system is minimized.

AC Control Module 
The AC module consists of the electronics for automatic control of the 
engine generator set: 
Electronic engine governor 
Electronic generator voltage regulator 
Automatic load sharing circuit for parallel operation 
Reverse power, under frequency, over-frequency, pulse loss and over- 
voltage protection 
DC Control Module 
The DC module consists of the electronics for automatic control of the SCR 
converter: 
Automatic load sharing system for the drawworks, rotary table and mud pump motors 
SCR firing circuits with ‘hard firing pulse’ output 
Gate suppression at approximately 150% of the highest single motor current limit 
All controls are designed to be ‘fool-proof’ 
Individual control of current limits for all drilling functions 
Zero throttle interlock