| 摘要 |
An electrically actuated audible alarm having a magnetic structure comprising an assembly of laminations is provided to reduce eddy current losses. With the reduction of eddy current losses, faster magnetic flux buildup is possible and an increased velocity of striker and/or armature movement. The increased striker velocity permits delivery of a given quantum of energy to the gong with a reduced striker mass which in turn facilitates even greater velocity. When actuated from an a.c. current source, a diode may be used in series with the winding to interrupt magnetic flux generation on negative half cycles and permit return movement of armature and striker. Conventional interrupter contacts may be used when actuated from a d.c. source. A series diode provides for d.c. loop supervision. A multiple lead permits the audible alarm to comprise part of the loop circuit and thereby provide a supervisory signal if an audible alarm is missing.
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