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What You Need to Know About Vertical Pump Motors

Shaft Types

Vertical pump motors will have a solid or hollow shaft design. Generally, solid shaft designs connect to the pump’s shaft with a keyed coupling. This configuration is very similar to most direct-driven horizontal motors. A hollow shaft vertical motor works a bit differently, though. The pump shaft goes inside the motor’s hollow shaft and couples at the top of the motor. These assemblies have an adjustment nut at the top that allows for simple modification of impeller depth or “lift”.

Thrust Loads

Knowing the thrust load and choosing the correct thrust bearing accordingly are two of the most important aspects when selecting an AC vertical pump motor. The thrust imparted from the pump to the motor should be obtained from the pump manufacturer. The motor’s thrust rating comes from the thrust bearing (or bearings) in the motor’s upper bearing housing. The thrust bearing is generally an angular contact bearing, spherical roller bearing, or, on larger motors, a Hydrodynamic Thrust Bearing (tilting pad) bearing.

Non-Reversing Ratchet (NRR) Assemblies

Many times, vertical motors are equipped with a non-reverse ratchet (NRR), also known as an anti-rotation assembly. Depending on the motor manufacturer, these configurations can be designed with either ball or pin assemblies. Ratchet assemblies have the very simple purpose of preventing the motor from spinning backward if water flow hits the impeller when the motor is off. These mechanisms prevent impellers from spinning backward and causing pump damage.

Sourcing Vertical Pump Motors

Most motor manufacturers make some form of a vertical motor.

All Systems Go

With decades of experience selling, servicing, monitoring, and storing electric motors and rotating equipment, HECO has the expertise to meet your vertical pump motor needs and solve any related challenges.