A: I talked to March Pump and here is what they said:
These pumps have an internal sensor that will shut the motor down if it reaches a temperature above it's normal operating temperature. Internal 203-205 degrees F.
Running on 50 Hz, will cause the motor to run 20% slower than at 60 Hz and have a 20% increase in current draw, causing it to run at a hotter temperature than 60 Hz.
The external temperature will reach somewhere around 160 Degrees F and not be able to touch it with your hands. These are designed to run 24-7 and as long as it is not tripping the shut off, it at normal working conditions.
He will need to take a 3 in 1 oil and lube the bearing on the end of the motor 2-3 times a year if it is running 24-7.