A 690V Variable Frequency Drive (VFD) refers to a drive with a rated input/output voltage of AC 690V (typically with a tolerance of ±10% to ±15%).
It is mainly used for speed control of high-power three-phase induction motors or synchronous motors.

Under the IEC system, 690V is considered the upper limit of low voltage, but in engineering practice it is often regarded as a “quasi-medium-voltage" level.

At the same power level:

380V → higher current

690V → current reduced by about 45%

Benefits:

Smaller cable cross-sections

Lower losses in switching devices, reactors, and busbars

More suitable for high-power continuous operation (≥200 kW)

Many industrial power systems directly provide:

690V / 50Hz

660V / 60Hz (common in mining applications)

Using a 690V VFD helps avoid:

Step-down transformers

Additional losses and maintenance costs

Key components (such as IGBT, electrolytic capacitor and rectifier bridge) adopt high withstand voltage level (such as IGBT withstand voltage of 1700V, electrolytic capacitor series use of 600V withstand voltage) to ensure stable operation under 690V voltage.
The internal circuit adopts high withstand voltage isolation module, optocoupler protection and high withstand voltage design between switch transformer windings to prevent electrical breakdown.

Reduce motor starting current impact and extend equipment life through soft start function.
The power factor compensation function reduces the reactive power loss and improves the active power utilization rate of the grid.
Support energy feedback braking (such as mine hoist, elevator and other scenes), and feed back the regenerated electric energy to the grid to save energy.

Operating temperature range: - 10 ℃ -+50 ℃, applicable to severe industrial environment.
Protection class: IP20
Heat dissipation design: independent air duct or forced air cooling to ensure stable operation under high temperature environment.