Overview
4
311596A
Overview
An electric motor (B) provides input to a 75:1 gear reducer (GR), which drives two fluid pumps (FP). See F
. 1. The
stroke positions of the two pumps are offset to achieve consistent flow from the pump assembly. See F
The optional sensor circuit includes a top dead center (TDC) sensor which assists software in measuring motor
speed, and a pressure transducer (PT) with circuit board, which measures fluid pressure at the pump outlet. The
Graco VFD software mimics the effect of a camshaft, constantly adjusting motor speed to keep steady fluid flow and
achieve minimal pressure variation. The output shaft of the gearbox and the connecting rods experience the effect of
the imaginary camshaft by speeding up when the pressure drops (pump lower is at a changeover) and slowing down
when pressure increases (both lowers are pumping).
The VFD can be controlled by a local control box mounted in the hazardous area, via communication protocol (such
as modbus), or directly from the keypad.
F
IG
. 1. E-Flo Plus Electric Circulation Pump
ti8317a
B
GR
PT
FP
FP
TDC
(behind
cover)
F
IG
. 2. Cutaway Showing Offset Stroke Positions
ti8321a
