| 摘要 |
An electric power switch or contactor of the 3-pole AC type or the like is provided with means making it capable of withstanding higher fault currents such as short circuit currents. This is done by providing the insulating contact carrier with integrally molded stops that will allow the spring-biased bridging contacts to be blown slightly open by the high electro-dynamic forces occurring during high fault currents but will limit such opening of the contacts to gaps small enough to inhibit the arc from moving from between the contacts. Instead of attempting to keep the contacts closed under such conditions which would require a large magnetic force, allowing the contacts to open this small amount eliminates the need for a larger magnet, reduces the blow-open force and, more importantly, the small gaps will retain the arcs between the contacts and will inhibit them from flashing out to other parts of the contactor with consequent burning and destructive effect. As a result, the device will remain reusable with replacement of the contacts and possibly only minor repair. |
