X/R Ratios

The approximate X/R data listed in these tables are representative of standard equipment in current production. The X/R values of this equipment change from time to time so that the up-to-date validity of the impedance values should be verified.

Typical values for generators, synchronous motors, power transformers, induction motors, utility sources, and reactors. (From ANSI Standard C37.010)

A. Large generators and hydrogen cooled synchronous condensers
  Range: 40-120
  Typical: 80
B. Generators and synchronous motors (See TABLE 8A)
C. Power transformer (See TABLE 8B)
D. Induction motors (See TABLE 8C)
E. Utility source
   1. Near generating plant
   Range: 15-30
   2. Long open-wire line
   Range: 2-16
   3. Typical
   Range: 5-12
F. Reactors
   Range: 40-120
   Typical: 80