| 摘要 |
In a system with a plurality of loud speaker enclosures, a supervisory system is provided to monitor the speaker coils. Each enclosure has a relay, and the relay winding is series-coupled with the speaker coil, to maintain the relay contact set closed when there is continuity in the speaker coil. A fuse, also series-coupled with the relay winding and speaker coil, is sized to blow when the speaker coil shorts and reduces the series circuit impedance. Accordingly either the speaker coil open condition or the speaker coil shorted condition effects de-energization of the relay winding and releases the normally-closed contact set to signal the speaker coil trouble condition.
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