Graco 3A0006EN-D User's Manual | Page 5
Overview
3A0006D
5
E-Flo Pump Operational Overview
An electric motor (B) provides input to a 75:1 gear reducer (GR), which drives two fluid pumps (FP). See FIG. 1. The
stroke positions of the two pumps are offset to achieve consistent flow from the pump assembly. See FIG. 2.
The optional sensor circuit includes a top dead center (TDC) sensor to measure motor speed, a position sensor (PS)
to measure motor position, and a pressure transducer (PT) to measure fluid pressure at the pump outlet. The Graco
ACS control module 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
electrical control module simulating the function of a 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 ACS module provides an analog drive signal to the VFD. Use one ACS module for each E-Flo pump. The ACS
module can be controlled by a local control box mounted in the hazardous area, or via communication protocol (such
as modbus).
FIG. 1. Electric Circulation Pump
ti8317c
B
GR
PT
FP
FP
TDC and
Position
Sensors
(behind
cover)
FIG. 2. Cutaway Showing Offset Stroke Positions
ti8321a