| 摘要 |
PROBLEM TO BE SOLVED: To accurately detect the resonance frequency of a carrying device which carries articles with vibration. SOLUTION: A vibrator 7 and a feeder control part 30 are provided in each electromagnetic feeder 1. The feeder control part 30 has an inverter 31 for supplying power to the vibrator 7, a vibration control part 32 for controlling the inverter 31 with drive pulses, a clocking part 33 for measuring a time (a current exceeding time) when a current supplied from the inverter 31 exceeds a reference value, and a pulse width setting part for setting the pulse width of the drive pulses and a frequency setting part 35 for setting the frequency of the drive pulses. The pulse width setting part 34 sets the pulse width as a pulse width d when the current exceeding time is measured while gradually increasing the pulse width of the drive pulses until the current exceeding time is measured. The frequency setting part 35 detects the frequency with the current exceeding time being the maximum, as the resonance frequency of the electromagnetic feeder 1, while changing the frequency of the drive pulses of the pulse width d. COPYRIGHT: (C)2007,JPO&INPIT
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