1. Search
  2. A-Z

Integral motor

The integral motor is also referred to as an integral drive or "intelligent" drive and is a three-phase asynchronous motor with integrated frequency inverter for continuously variable speed control.

This means that an integral motor is a compact drive system for pumps consisting of a motor (electrical machine), a power-adjusting element (frequency inverter) and a microprocessor for open-loop and closed-loop control purposes. See Fig. 1 Integral motor

Integral motor: Compact drive system with motor, frequency inverter and microprocessor (process view) Fig. 1 Integral motor: Compact drive system with motor, frequency inverter and microprocessor (process view)

Some solutions involve permanently integrating the frequency inverter in the motor, while others allow different makes of motor to be used. The latter offer greater flexibility and can, for example, be retrofitted in installed pump systems. See Fig. 2 Integral motor

Integral motor: Mounted on a horizontal and vertical pump Fig. 2 Integral motor: Mounted on a horizontal and vertical pump

Motor-mounted or integrated centrifugal pump frequency inverters have key benefits as compared to separately installed solutions. For example, there is no need for components such as the motor protection switch, wiring, overload or time relay, and expensive shielded cables from the frequency inverter to the motor terminal box.
See Fig. 3 Integral motor
Integral motor: Comparison of initial investment costs of variable speed Fig. 3 Integral motor: Comparison of initial investment costs of variable speed integral motor and variable speed drive with separate frequency inverter

This, in turn, minimises the electrical load placed on the motor and leads to fewer electromagnetic compatibility (EMC) issues. The closed-loop control system is integrated and eliminates the need for an external device.

EMC filters integrated in the drive improve operating reliability as does the built-in pump and motor protection equipment. All functions required for safe and reliable operation of the centrifugal pump are thus already incorporated.

Integral motor