Envipco U48DFF, Service Manual

Page: 43 / 100

3-21
AC Motor Control Box
3.8. AC Motor Control Box
The
AC
Motor Control Box houses the
AC
electrical components. Figure 3-21 shows the components
and connectors of the
ULTRA
48
AC
Motor Control Box. The connectors that are used for development
and testing are not labeled.
The
ULTRA HDS AC
Motor Control Box differs in that it has two Variable Frequency Drives with corre-
sponding fuse blocks, which control the two compactor motors.
FIGURE 3-21.
ULTRA 48 AC Motor Control Box Components
3.8.1. Terminal Block
This component receives the incoming single-phase
AC
power from the power cord. It is located inside
of the
AC
box, as shown in Figure 3-21.
3.8.2. Variable Frequency Drive
The Variable Frequency Drive (
VFD
) converts single-phase input to three-phase output for the compac-
tor motor. It varies the frequency of output to govern the speed of the compactor, and it monitors the
amperage for current overload. If the compactor stalls and causes a current overload for a certain