REO is building its first water-cooled resistors for ABB to test converters used in shipping, railway engineering and water power plants. ABB already uses water-cooled systems but this project represented an opportunity for REO to apply knowledge gained in research areas from inductor and resistor construction to entire control boxes.

The load unit is comprised of 15 individual resistor groups each dissipating 30,000 kW of power using a coolant distribution system based on the REOhm BWD 330 resistor.

Claiming up to 88% space saving for the BWD 330, the coolant distribution is set up in a Tichelmann Coil configuration, using a dual-pipework fluid transfer method similar in concept to the electrically equivalent ring main circuit typically found in UK homes.

If one resistor is located nearest to the coolant supply distributor connection on one side, then the return is collected at the furthest distance from the other distributor. All resistors can be locked individually and there is a needle valve on the feed side, allowing flow rate to be offset to the flow resistances on individual resistor groups. The feed arrangement features a ball valve on each return with which to shut the line.

The low-weight REO BWD 330 braking resistor and its unique cooling system allows a large space saving, high ingress protection to IP 66 and higher power levels up to 60kW, which is not possible with conventional air cooling. The BW D330 is also available in compact form with an integrated braking chopper. The units can also be connected in parallel to provide much larger power capacities if required.

“Water-cooled components offer the highest degree of efficiency in cooling and REO offers not only individual components but also complete systems and pre-wired solutions,” claimed Steve Hughes of REO UK. “These include water-cooled load banks for test facility use, as well as complete EMV solutions for water-cooled inverters with increased power for wind, solar, and industrial applications.”