06-10-2011 09:17 PM
CAT had four generators it sold as CAT generators, the SRCR, SRSE, SR4 and SR4B. The SRCR and SRSE generators that were a slip ring design excitation system, the SR4 family are all pilot excited.
As I remember the SRCR evolved from a GE design that CAT primarily used for the oil and gas market, and I think they were built by a few different companies based on the ones I've seen. The SRSE was built by Century Electric for CAT. As generator design evolved CAT and Century introduced the SR4. At what point Century stopped and Leroy Somer started building CAT tail ends is about the time the SR4B came along, maybe one of the CAT folks can verify that for sure. The SR4 family of generators has seen 4 analog and 2 digital regulators. The VR1 (A1 module type) VR2 (tray type), VR3 and VR6 are the analog AVR's that were used. The digital regulators were the DVR and the CDVR.
Hope that helps, Mike L.