| 摘要 |
<p>The electrically driven siren comprises an electric motor (M) driven by power applied to terminals (26) and affording a base plate (20) on which other siren elements are mounted in the assembly process. An impeller (1) is driven in rotation by the motor (M). Radial fins (2) initiate centrifical air flow through baffled ports (6, 7) in the impeller skirt (3). A cowling (10) fits non rotatively over the impeller. Ports (18) allow air to freely enter the impeller whose exit ports (12) interact with the baffled impeller ports to provide the siren effect.</p> |
