Servo drives as field exciters.

[damelman]

I work on a steel processing line that has separately excited 310 volt DC Motor generator sets. The 1960 vintage SCR/ Magnetic Amplifliers are getting harder to get parts for so I suggested we attempt to replace the static exciters with Servo amplifliers normally used in CNC applications. Digital drives to replace the MG sets would cost $2.5 Million Dollars. $100,000 has been allocated for this project to install five to nine servo amplifliers on the generator and motor fields of one section of this process line. General Electric
process control engineers are working on the project.

[Al_The_Man]

If it is just for field excitation, there should not be a great deal of current, do you know what it is presently?
It is possible that A-M-C style PWM drives may work OK.
Al.

[damelman]

Al it's like you read the GE field technician's mind. 25 amp AMC is what he specified was on order. Don't know the model number as of yet. I guess the model will use an external resistor to supress spikes during regen.