Description

This 0-5V regulator allows precise dimming of the pump speed (0 – 5 VDC). For use with Iwaki RD-12 direct drive pump and Iwaki NRD serie.

Operating Principle

The RD & NRD Series pumps are a canned motor type centrifugal pump driven by a DC brushless motor. The magnet incorporated with the impeller is directly rotated in the pump chamber by the magnetic force of the motor to discharge the liquid from suction port to the discharge port.

The RD-12 mag-drive pump can be controlled by 0-5V external control.  The 0-5VDC external variable signal is used for just a simple flow control, and a flow rate is not even in proportion to the signal voltage.  The pump is able to run with no 1-5VDC signal generator when electrically wired as follows. In this case the pump runs at the maximum speed.

Direct Drive Technology

A direct drive brushless DC design is categorized as an integral pump and motor assembly including driver electronics. Similar to a magnet drive design there is no direct connection between the motor shaft and the driven element. However the pump does not employ an external drive magnet mounted to a motor shaft to transmit the motor torque to the internal driven magnet assembly. Instead, the torque is transmitted directly by a brushless DC motor (BLDC).

The inner rotating magnet assembly is positioned as the rotor of a motor. The motor windings are wound around the rear housing. The inner rotating magnet assembly is driven by the rotating magnetic field of the BLDC motor. Commutation is performed electronically using sensors to detect the position of the inner rotating element. The sensor inputs are used by the driver circuit to energize the motor windings. The induced magnetic field drives the inner magnet assembly. This design eliminates the need for a separate motor armature, motor bearings, drive magnet mounted to the motor shaft, and shaft seals. As with magnet drive designs, the direct drive seal-less structure also eliminates leaks and problems involving seal replacement. The resulting package is compact, efficient and provides for a longer service life.

Additional information