The machines operate off of 480 3 phase but have transformers that provide 110V AC for control voltage. I am not 100% sure that the voltage is the problem but on some of the machines hour meters seem to fail allot more often usually within 300 - 400 hours. The voltage on these machines is 128-135V AC. And the hour meters seem to run hot. On machines with a more constant 110V the meters work fine.
These are a CRAMER 635G Meter - AC Voltage Hour and Minute Meters
Permanent magnet motor provides accuracy: ±50msec. per Start/Stop; 100% when running at nominal frequency. Input voltage: min. 110V, max. 120V; 60 Hz, 3 watts. Flange mounts in 2-1/4" dia. hole; mounting hardware included. Also includes 6" wire leads. Indoor use only. UL Recognized and CSA Certified. high-impact black styrene housing ,Whole numbers are white on black; decimal numbers are black on white Continuous-duty cycle.