M-0404 Voltage Isolation Transformer

  • Terminals are brass studs No. 10–32 with one lock washer, flat washer, and regular nut
  • The core and coil assembly is encased in a thermoplastic shell and filled with resin
  • It is desirable to use a 1.6 amp fuse in the secondary to protect the transformer
  • The M-0404 is primarily intended to transform 69 Vac control voltages to 120 Vac for operation with most Load Tapchanger controls
  • Alternately, it may be useful (at reduced VA capabilities) of transforming 208 Vac nominal control voltage to 120 Vac by reversing the primary and secondary connections
  • Each transformer includes two plastic terminal covers
  • Approximate weight: 7.75 lbs


  • Frequency: 60 Hz
  • Nominal Input Voltage: 69.0 Vac
  • Secondary Voltage: 120 Vac
  • Insulation Level: 0.6 kV, BIL 10 kV full wave
  • Ratio Accuracy: Better than ± 1% up to 20 VA over operational temperature range of -40° C (-40° F) to +85° C (+185° F)


  • IEEE C57.13
  • IEC 60044-2
  • UL E93779
  • CSA LR89403