Caterpillar has recently published a white paper on the subject titled :  CAT® INTERNALLY EXCITED (IE) ALTERNATORS.  

Joining us today from his home in Northern Ireland via the Cat Electric Power Hotline is the paper's author - Roger Rosborough.  Roger has a Masters and PhD in Engineering from Queens University in Belfast N. Ireland and has16 years experience with Caterpillar working in Mechanical Design, the Technology department developing cooling systems and most recently as a Marketing  Industry Consultant.

Today we'll be discussing why, in most cases, Cat's IE alternator should be given equal consideration to most PM alternators.