At this point, all of the hard stuff is done... the expensive, noisy ON/OFF switch (contactor box), the mounting for the VFD itself, etc. All that remains is to make the final connections between contactor, VFD, and motor. Then, hopefully a'la Dr. Frankenstein, I'll be able to say "It's ALIVE! ALIIIIIVE!" (O.K. it's early and I haven't finished my coffee yet!)
|The back plate was too thick for a simple hole which
would allow the fittings to be secured by a nut. Instead,
they were bored open, and while still in the mill, tapped
1/2" NPT with a rarely used, rusty old carbon steel
The fitting seen here is a simple set-screw socket for armored cable sheathing.
|The power inputs for the VFD are on the front and to
the left, thus this cable is for the 240V 1P input from
the contactor box. Within the box, I have a source of
100VA, 120VAC via the transformer. The original plan was
to use this power to run a cooling fan for the motor,
augmenting the built-in fan. At low RPM, the efficiency
of the built-in fan is very poor. Before actually
mounting a fan, I wanted to test everything and see just
how hot the motor gets. Inside this sheathing, then, is a
pair of 120V hot lines, a grounding line, and a 14 guage
coper wire for 120V from the transformer.
For now, it remains unattached.
|On the other side of the backplate, the line-in wires are routed. Inside the plastic sleeve are the power lines, which connect to a pair of screw terminals inside the VFD. The ground wire (white but clearly labeled GND with a correct label) is firmly connected to the aluminum backplate.|
|Power-on test! No problems.|
|Three 10 guage stranded wires, plus ground, were
mounted inside another short section of armor sheathing,
and routed to the motor. Inside the motor junction box,
the connections were made with a set of wire nuts. As it
came from the factory, the wires were set for 480VAC.
Resetting the connections for 240VAC took just a minute
The junction box lid was reattached.
|Finally, the Fenner belt length was adjusted and