Neumotors 8819M Multirotor (Baureihe)

The Neumotors 8819M is a heavy-lift outrunner from the US maker Neumotors for large multicopters. The type code gives a stator of 88 mm diameter and 19 mm height; the motor measures 102 mm across and 50 mm in height on the outside.

It weighs 915 g, maximum power is 5 kW and continuous power is 2.5 kW. In this series the voltage is stated not in cells but in volts: the standard winding works up to 130 V, a high-voltage winding up to 450 V. There is a technical reason, since at equal power the current falls as voltage rises, and losses and cable cross-section fall with it.

Aircraft of this power class often exceed 25 kg take-off mass; above that the EU open category ends and operation needs an authorisation in the specific category. Voltages up to 450 V are no longer extra-low voltage: assembly, cabling and maintenance belong in the hands of qualified staff, with insulation testing and protection against contact. The batteries for such a drive consist of very many cells in series and, for air transport, sit far above the 160 Wh limit.

KV is set by the system voltage and the propeller size. The ESC must be rated for the voltage of the chosen winding. Before use, check the winding's insulation resistance, bearing run and the bell's concentricity; heat and high voltage stress the insulation more than in low-voltage motors.