摘要 |
<p>A system is disclosed for verifying the operativeness of a crowbar circuit which normally protects an electrical device in a series circuit with a power supply. The crowbar circuit includes means for sensing fault current in the series circuit and a crowbar switch responds to the sensing means for protecting the electrical device by directing the fault current away from the electrical device. The system includes verification testing means including a fuse and actuatable pneumatic switch connected together in series for, when said pneumatic switch is actuated, providing a short circuit across the crowbar switch to verify the operativeness of the crowbar circuit which, if not operative, causes the fault current to flow through and blow out the fuse.</p> |