A 是一种自动水泵，由电机驱动，它能从污水池或低点排除排污量，不包括原污水。There are two basic kinds of sump pumps: pedestal and submersible. Either will work well with proper maintenance. Pedestal sump pumps are powered by an electric motor which sits on top of a pedestal. The pump itself sits down in the sump, but the motor sits on top, out of the pit. A pedestal pump motor is not designed to get wet. The pump is turned on and off by a ball float. One advantage of this type of pump is that the on/off switch is visible, so the action of the ball float can be easily seen.