High-speed Frequency Converter for Multi-spindle Operation in PCB Drilling Machines

On behalf of a manufacturer of PCB drilling machines SIEB & MEYER has developed a compact and cost-effective frequency converter that is adapted to the existing machine unit and permits sensorless operation of up to eight high-speed spindles.

Client requirements:

The client is a manufacturer of PCB drilling machines and wished for a frequency converter that can be optimally integrated into his existing machine construction.

The existing servo amplifiers should supply the frequency converter with power from the DC link.

For the purpose of saving costs one central frequency converter should operate up to eight high-speed spindles in the speed range up to 480,000 rpm without sensor.

Customized Solution by SIEB & MEYER:

The customized solution is based on the serial device FC2 that features a device topology with controlled DC link. This permits the operation of low-inductive asynchronous motors without additional motor chokes via pulse amplitude modulation (PAM) up to an output frequency of 8,000 Hz (480,000 rpm). The functional spectrum of the standard device already includes the parallel operation of up to eight asynchronous motors as well as the separate evaluation of the temperature sensors.

SIEB & MEYER adapted the electronics of the power supply unit and the device construction to the machine conditions. During this process the engineers were able to reduce not only the installation space but also the wiring work.

The most important details in short:

• supply voltage 350 VDC
• PAM modulation, controlled DC link
• output: 3 x 0..230 VAC, 0..8,000 Hz, S1: 13.2 kVA
• integrated evaluation of up to eight temperature sensors
• sensorless operation of up to eight asynchronous motors