Frequently Asked Questions

Yes. Due to the unique design of the lubrication system, a vacuum is pressent inside the traction drive inhibiting oil from leaking into the air stream.

Yes. Our fuel cell compressors are designed for supplying air to the cathode side of a fuel cell stack.

In fact, there are many names for this vital fuel cell stack component: air or cathode pump, compressor or supply etc. 

Yes. The motor, traction drive lubrication system and automotive motor controller are all liquid cooled, and require an external cooling circuit.

Yes. At least 300VDC is required to enable full speed, it mainly depends on the chosen model.

All models can be ordered with an Industrial motor controller, enabling the unit to be used in a setup supplied by the electrical grid.

Yes, because of our traction drive design, the Rotrex fuel cell compressor can operate at any point for any desired period. It is important that the fuel cell compressor can deliver maximum power for longer durations, handling incline, takeoff or other high-power situations. 

In fact, lifetime testing at Rotrex is performed at maximum load continuously. 

Yes, our electrical compressors are not limited to be used in fuel cell applications. 

Suitable for vacuum as well as pressurized applications, delivering a steady, non-pulsing airflow, our compressors are highly versatile, compact and reliable.

Yes, to exploit the very high aerodynamic efficiency the centrifugal compressor needs to be operated at a certain pressure ratio.

On the left side of the map is the surge line, here the compressor cannot be operated. 

On the right side, the compressor has lower than 50% aerodynamic efficiency and is operating in choke. 

Pressure Ratio (or PR for short) is the difference between inlet and outlet pressure. This is to accommodate operation if a vacuum is created on the inlet side of the compressor.

The outlet gauge pressure is calculated by multiplying the inlet absolute pressure with the PR.