Simply by paying strict attention to the magnet’s duty cycle. Duty cycle is the time the magnet is in use. More specifically, duty cycle is the percentage of time a magnet is to receive its rated voltage in any 10-minute period. Most magnets are designed to operate at a 50 percent or 75 percent duty cycle.
For example, in any 10-minute operating period, the magnet can run five minutes on, five minutes off for a 50 percent duty cycle. For a 75 percent duty cycle, the magnet can run for 7.5 minutes, off for 2.5 minutes.
During the off cycle, the magnet is given time to cool and – provided this rule is not broken – should allow a magnet to operate at its designed rating throughout the day.