The invention relates to a shaft contact device 1 to make an electrical connection between a shaft and an earth point.

Device 1 has a bracket 10 for connection to a point spaced from the rotating shaft, base member 20 mounted on the bracket 10, a head member 30 having at least one electrically conductive brush 34A, 34B to engage the shaft. A pair of arms 40A, 40B each has a first end connected to spaced pivot points on the base member and a second end connected to spaced pivot points on the head member. A spring means 50 biases the head towards the shaft to engage the brush on the shaft.

In use the base member, head member and spaced arms forming a parallelogram arm whereby the head member brushes contact the shaft at a constant angle as the brushes are worn.

A slip ring assembly includes: at least one first conductor group, and at least one second conductor group. Each first conductor group includes a first conductor and a second conductor, and the first conductor and the second conductor are configured as annular shapes, respectively. Each second conductor group includes a third conductor and a fourth conductor, the third conductor and the fourth conductor are configured as annular shapes, respectively. The first conductor, the second conductor, the third conductor and the fourth conductor are arranged to be apart from each other. A first current having a first phase and a first amplitude is configured to flow through the first conductor, a second current having a second phase and a second amplitude is configured to flow through the second conductor, a third current having a third phase and a third amplitude is configured to flow through the third conductor.

A slip ring assembly includes: at least one first conductor group, and at least one second conductor group. Each first conductor group includes a first conductor and a second conductor, and the first conductor and the second conductor are configured as annular shapes, respectively. Each second conductor group includes a third conductor and a fourth conductor, the third conductor and the fourth conductor are configured as annular shapes, respectively. The first conductor, the second conductor, the third conductor and the fourth conductor are arranged to be apart from each other. A first current having a first phase and a first amplitude is configured to flow through the first conductor, a second current having a second phase and a second amplitude is configured to flow through the second conductor, a third current having a third phase and a third amplitude is configured to flow through the third conductor.

An externally excited electric machine comprises a rotor as well as a contact device having at least one sliding contact element positioned against a contact segment of the rotor for transmitting an exciter current, wherein the sliding contact element is integrated in an electromagnetic actuator, by which it can be controlled to move between a position lying against the contact segment and a position spaced apart from it.

An externally excited electric machine comprises a rotor as well as a contact device having at least one sliding contact element positioned against a contact segment of the rotor for transmitting an exciter current, wherein the sliding contact element is integrated in an electromagnetic actuator, by which it can be controlled to move between a position lying against the contact segment and a position spaced apart from it.

The invention relates to a shaft contact device 1 to make an electrical connection between a shaft and an earth point. Device 1 has a bracket 10 for connection to a point spaced from the rotating shaft, base member 20 mounted on the bracket 10, a head member 30 having at least one electrically conductive brush 34A, 34B to engage the shaft. A pair of arms 40A, 40B each has a first end connected to spaced pivot points on the base member and a second end connected to spaced pivot points on the head member. A spring means 50 biases the head towards the shaft to engage the brush on the shaft. In use the base member, head member and spaced arms forming a parallelogram arm whereby the head member brushes contact the shaft at a constant angle as the brushes are worn.

The invention relates to a shaft contact device 1 to make an electrical connection between a shaft and an earth point. Device 1 has a bracket 10 for connection to a point spaced from the rotating shaft, base member 20 mounted on the bracket 10, a head member 30 having at least one electrically conductive brush 34A, 34B to engage the shaft. A pair of arms 40A, 40B each has a first end connected to spaced pivot points on the base member and a second end connected to spaced pivot points on the head member. A spring means 50 biases the head towards the shaft to engage the brush on the shaft. In use the base member, head member and spaced arms forming a parallelogram arm whereby the head member brushes contact the shaft at a constant angle as the brushes are worn.