1. What is a motor-pump assembly
A motor-pump assembly is the integration of pump and motor on a common baseplate, connected by flexible coupling. It is the most reliable way to install an industrial pump because alignment is done in a controlled factory environment with precision instruments.
Misalignment is the second leading cause of industrial pump failure (after dry running). When the assembly arrives factory-mounted, this risk is virtually eliminated.
2. Motor-pump assembly components
A complete motor-pump assembly consists of five main components:
- Pump — centrifugal (FBCN), external gear (FBE), internal gear (FBEI) or thermal oil (FBOT). Sized for application flow, pressure and fluid.
- Electric motor — typically WEG, with power selected per power reserve (20% up to 2 hp, 15% up to 20 hp, 10% above 20 hp — FBCN manual data). Available in 2 or 4 poles, 220/380/440V.
- Flexible coupling — transmits motor torque to pump with tolerance for minor residual misalignment (angular, parallel and axial). Common types: grid (Falk), jaw (Lovejoy), flexible disc.
- Coupling guard — metal cover preventing access to rotating coupling. Mandatory per safety standard (NR-12).
- Metal baseplate — common structure supporting aligned pump and motor. For FBCN, the baseplate is sized per ASME B73.1. Can be painted carbon steel or stainless depending on environment.
3. Factory assembly advantages
Factory assembly of the motor-pump unit offers significant advantages over field assembly:
- Precision alignment with dial indicator or laser — impossible to replicate at construction site
- Hydraulic bench test before shipping — performance guarantee per curve
- 60-80% reduction in field installation time
- Single manufacturer warranty on entire assembly
- Elimination of incompatibilities between components from different suppliers
4. How to specify a motor-pump assembly
To request a motor-pump assembly from FB Bombas, provide:
- Fluid data — name, viscosity, density, operating temperature and solids presence
- Operating conditions — flow (m³/h or L/min), pressure (bar or kgf/cm²), available NPSH
- Available electrical voltage — 220V, 380V, 440V, frequency (50 or 60 Hz)
- Area classification — explosion risk (classified areas require Ex motor)
- Materials — cast iron, stainless steel or special alloys per chemical compatibility