These are used mainly on pumps (water wells, for example). Vertical solid shaft
motors are coupled with the pump at the lower end of the shaft. Vertical hollow shaft motors are coupled with the pump at the top side of the shaft. The pump has a longer upper shaft that goes through the motor shaft and is bolted at the top. Such motors have drip covers and very good internal insulation (special varnish). Some feature an oil reservoir for lubrication
. These motors have a vertical P-Base
frame. Some motors feature a non-reverse ratchet that prevents pump backspin (when off) by the column of fluid that falls over the impeller. Depending on the amount of water and pressure, backspin can reach dangerous speeds if unchecked.