EX air ministry mystery salvaged NOS Parmeko style special purpose HT and LT transformer measures off load 278-0-278V  5.63V 6.9V 6.9V 9.92-0-9.92V 266.4V 97.2V  Estimated 115V primary   Estimated 50VA measures 3.5" x 4" x 4.5"  Voltages/connections as shown