from The Century Dictionary.
- In electricity, provided with series-windings sufficient in number to give constant difference of potential, not at the terminals of the machine, but at some other point in the circuit: said of certain generators which have both shunt and series field-coils.
Sorry, no etymologies found.
If it is found that the speed of the water wheel drops 25 per cent between no load and full load, a dynamo with field coils over-compounded to this extent would give a fairly constant regulation.
On the other hand, if his dynamo was over-compounded 25 per cent -- that is, if it gained 28 volts from no load to full load, the system would be perfect.