Converting Between 50 Hz And 60 Hz Without Derating The Load

What Changes When The Frequency Changes

Induction motor speed follows supply frequency. Transformer and motor magnetising current rises when frequency falls at the same voltage. Fans and pumps driven by those motors shift along their curves, so cooling and flow change with them.

Why Voltage And Frequency Travel Together

Keeping the voltage to frequency ratio constant is what protects the magnetic circuit. A converter that sets both, rather than a transformer that sets only voltage, is what makes an imported machine behave as designed.

Static Conversion In Practice

A static converter rectifies the incoming supply and rebuilds the output with an IGBT inverter stage under space vector PWM control. Frequency accuracy of 0.01 and stability within 0.01 percent from no load to full load come from that control loop rather than from rotating mass.

Shore Power Static Frequency Converter

Harmonics Are Part Of The Specification

The rectifier front end decides what the installation puts back into the grid. A 6 pulse rectifier gives input current THD of 35 percent or less, a 12 pulse rectifier 6 percent or less, and a PWM rectifier 5 percent or less at full load. Pick against the limit the utility or port authority imposes.

Bench Scale Conversion

For test and QA work the same problem appears at a few kVA instead of a few thousand. A programmable AC source covering 40 Hz to 499.9 Hz handles it on the bench.

HPA Programmable AC Power Source