up to 1500 kVA
Service- and maintenance works of the rotating converter can be done by every trained technician. A static converter can only be maintained from a specialist from the supplier/OEM. This can influence the service cost significantly.
The MTBF-Value (meantime between failure) of rotary converter is above 50.000 hrs. The MTBF of static converters is significanly lower due to the higher number of parts and electronic components.
Spares for rotary converter are available in almost every country of the world.
- Grid loading effect:
When planning static systems, you have to consider, that because of current and voltage interferences caused by static converters the Mains transformer has to be oversized by about 20%. Further on only such consumer can be connected to the transformer which are not influenced by the interferences. (Problems with UPS or diesel gen sets).
The efficiencies of rotary converter and static converters are almost the same. The additional losses caused by the inverters’s harmonics are not included.
- Distortion factor:
The intensity of harmonics of rotary converters is much lower than those from static converters.
- Suppression of radio interference:
Suppression acc. N and K acc. VDE 0875 or MIL-standard can be fulfilled by rotary converter. Static converter already have problems with N acc. VDE 0875.
- Input power factor:
The power factor is automatically controlled within the range of 0.9 to 1.0 (reactive load supply) at 50% to 100% of nominal load. Static converter consume reactive load (cos phi 0,75 - 0,85) and therby require a capacitor bank.
Rotary converter have better overload endurability than static converter.
- Shock load response:
By fast regulating the voltage at shock load often requests an enlargement of the system of static converter. Rotary converter have the capability to endure peak values of shock loads of 20 times nominal current (one half wave) or 3 times nominal current for several seconds.
- Overcurrent discrimination:
The request operating static converter systems without fuses is not possible or just under certain conditions. Current peaks up to 40x nominal current for one half wave are not seldom for static converters. To obtain a selectivity highest care is necessary when selecting fuses. The installation efforts for static converters is much higher than for rotary converters.
- Indirect coupling (Galvanic separation):
An indirect coupling is provided only by rotary converter.
- Voltage peaks and EMP, NEMP:
Electronic parts are more responsive against voltage peaks and high magnetic fields than windings are.
Shock proof systems with static converters are only limited practicable.