Hi PJCP,
It is a 1000-Ohm Thermistor. It is used on the SS-200 and SS-400 Xenon Lamp Power Supply on a Woollam System. Here is an alternative part number from the OEM.
Part Description: THERMISTOR, PTC, 480 VOLT, 1K OHM
MFG PN: PTCEL13R102SBE
MFG: VISHAY
MOUSER PN: 594-PTCEL13R102SBE
Hope...