FZ-J Type Magnetic Powder Brake

FZ-J type (shaft connection, base support) magnetic powder brake

Structure and working principle

The magnetic powder brake is composed of a rotor, a stator, and a yoke containing excitation coils. The three parts are assembled relatively concentrically, forming a relatively rotatable whole. In the annular gap (working chamber) between the rotor and the stator, highly magnetic alloy magnetic powder is filled.

When there is no current passing through the excitation coil, the magnetic powder in the working chamber is in a loose state. Under the action of the centrifugal force generated by the rotor, the magnetic powder is evenly flung onto the inner wall of the rotor. The weak interaction between the rotor and the stator causes the magnetic powder brake to be in an unloaded state, with no torque output.

When current passes through the excitation coil, the working magnetic flux is generated in the yoke. The magnetic powder in the working chamber is connected in a chain along the direction of the magnetic flux. The magnetic powder brake generates torque by the frictional force between the magnetic powder and the magnetic powder, and between the magnetic powder and the working surface, as well as the shear force between the magnetic powder chains at this time. The magnetic powder brake is in the loaded state.

When the current is cut off, the magnetic flux disappears along with the disappearance of the excitation current. Under the effect of gravity, the magnetic powder returns to a loose state and is thrown onto the inner wall of the rotor under the action of centrifugal force. The magnetic powder brake is then in an unloaded state again.

Feature

The excitation current has a linear relationship with the torque.

When the excitation current remains constant, its torque is not affected by the rotational speed of the rotor. That is to say, there is no difference between the static friction torque and the dynamic friction torque, and thus the constant torque can be stably achieved. This feature is applied in power testing. Users only need to adjust the excitation current to accurately control the torque, thereby effectively controlling the magnitude of the load resistance.

When sliding continuously, the friction parts are bound to heat up and may even burn out. However, this equipment is equipped with a complete heat dissipation device. Even after long-term operation, it will not overheat and has a long service life.