The Model 590J is a modestly priced, lightweight
field portable instrument designed to audit P.T. and C.T. installations in a utility system. The Model 590J is used for many routine workshop tests, as well as field testing, to an accuracy of 0.02%. It is optimised for testing metering C.T.s, but can also test protection C.T.s for current and phase error at normal burden.
The Model 590J has an internal solid state voltage
source to test P.T.s and C.T.s. The source can
generate up to 160V at 50Hz or 60Hz, and 2V at
1.6kHz. To avoid spurious results caused by 50Hz
or 60Hz pickup from nearby equipment, the tests
are carried out at 51Hz or 61Hz and the microprocessor control locks on to the 51Hz signal only.
The software extrapolates the 51Hz or 61Hz test
results for an actual 50Hz or 60Hz performance.