A robotic system comprising: a robot arm comprising a series of links interconnected by articulated joints; and a motor arrangement for driving at least one of the articulated joints, the motor arrangement comprising: a motor having a rotor, a stator, and at least three windings (305a,b,c) mounted on one of the rotor and the stator for acting on the other of the rotor and the stator, and a plurality of inputs (307a,b,c) coupled to the windings; a control circuit configured to operate in a driving mode in which it dynamically energises the windings (305a,b,c) via the motor inputs (307a,b,c) so as to cause the rotor to rotate relative to the stator, the control circuit being further configured to operate in a braking mode in which it continually connects the at least three windings (305a,b,c) to a common rail to form a closed current path to induce braking of the rotor relative to the stator, characterized in that the control circuit is configured to enter the braking mode in response to a trigger exogenous to the motor indicative of a fault condition; and by a trigger circuit configured to cause the control circuit to enter the braking mode when a supply voltage of the control circuit drops below a predetermined value. a robot arm comprising a series of links interconnected by articulated joints; and a motor arrangement for driving at least one of the articulated joints, the motor arrangement comprising: a motor having a rotor, a stator, and at least three windings (305a,b,c) mounted on one of the rotor and the stator for acting on the other of the rotor and the stator, and a plurality of inputs (307a,b,c) coupled to the windings; a control circuit configured to operate in a driving mode in which it dynamically energises the windings (305a,b,c) via the motor inputs (307a,b,c) so as to cause the rotor to rotate relative to the stator, the control circuit being further configured to operate in a braking mode in which it continually connects the at least three windings (305a,b,c) to a common rail to form a closed current path to induce braking of the rotor relative to the stator, characterized in that the control circuit is configured to enter the braking mode in response to a trigger exogenous to the motor indicative of a fault condition; and by a trigger circuit configured to cause the control circuit to enter the braking mode when a supply voltage of the control circuit drops below a predetermined value. a motor having a rotor, a stator, and at least three windings (305a,b,c) mounted on one of the rotor and the stator for acting on the other of the rotor and the stator, and a plurality of inputs (307a,b,c) coupled to the windings; a control circuit configured to operate in a driving mode in which it dynamically energises the windings (305a,b,c) via the motor inputs (307a,b,c) so as to cause the rotor to rotate relative to the stator, the control circuit being further configured to operate in a braking mode in which it continually connects the at least three windings (305a,b,c) to a common rail to form a closed current path to induce braking of the rotor relative to the stator, characterized in that the control circuit is configured to enter the braking mode in response to a trigger exogenous to the motor indicative of a fault condition; and by a trigger circuit configured to cause the control circuit to enter the braking mode when a supply voltage of the control circuit drops below a predetermined value. <EOS>