Equipmake unveils electric motor ‘believed to be the most power dense in the world’

Making its debut at this years’ Future Propulsion Conference in Solihull, the HPM-400 is an advanced high power, short duration motor originally specified as a high-performance rocket fuel pump for Helensvale, Australia-based Gilmour Space Technologies for use in its Eris rocket programme.

According to Equipmake, the HPM-400 has applications in high-performance environments due to technological and packaging innovations that allow the motor to withstand extreme acceleration while operating at atmospheric pressure and in space.

Ian Foley, CEO of Snetterton, Norfolk-based Equipmake, said the first prototype took six months to develop, and that the motor did not require vacuum tests.

He explained that compared to other systems, the motor must keep rocket fuel out of the electrical motor space, so it must resist internal pressure from inert gasses supplied from the rocket.

Foley said: “These vent slowly into the fuel through a labyrinth seal to prevent fuel ingress in to the motor. Therefore, we have to pass more stringent casing pressure tests. Similarly, the matched inverter had to resist internal pressure in order to maintain sea level electrical clearance. The alternatives, larger internal air gaps or encapsulating all the motor internals, came with significant mass penalties.”

He continued: “Compared to our other products where a validation vibration test is performed on the design, these individual motors and inverters all go through an acceptance vibration test in line with standard space industry practice.”

With a maximum motor speed of 20,000rpm, peak power/torque of 400kW/250Nm, yet a mass of just 30kg for the motor only, the HPM-400 is believed to be the most power dense in the world. Combined with its integrated silicon carbide inverter, which weighs 10kg, the entire system weighs in at 40kg.