Allen Bradley, 1397 Dc Drives. They were only used in labs for electrical apprenticeship. They are all in working condition and in like new condition. Input Voltage and Frequency Ratings Nominal Voltage 207 to 253 VAC or 414 to 506 VAC (Horsepower-rated drives) 342 to 437 VAC or 374 VAC to 477 VAC (Current-rated drives) Nominal Line Frequency 50 or 60 cycles per second Frequency Variation + 2 cycles of nominalAllen Bradley