10
9. Final assembly as follows:
• Check that the electrical E-frame and armature
assemblies are positioned with gap bars provided.
(Hand tight).
• Attach the tie bar to the rear of the body housing
using the existing rear tuning spring stack, and
bolts. (Tighten).
• Attach lever arm assembl.y. (Hand tight).
• Connect the tie bar to the front of the armature
adapter. (Torque - see Table 1).
• Check clearances. (Gap bars).
• Tighten front spring stack. (Torque - see Table 1).
• Tighten rear spring stack. (Torque - see Table 1).
• Tighten electrical E-frame assembly. (Torque - see
Table 1).
• Tighten lever arm assembly. (Torque - see
Table 1).
• Check all fasteners. (Check torque - see Table 1).
THE Hl-VI MAGNETIC DRIVE
CIRCUIT (RARE EARTH)
Old-style electromagnetic equipment has an inefficient
attract-release type operation, where a mass mounted
on springs is attracted by a DC electromagnet and
returned to its original position solely by the springs. The
new Hi-Vi method incorporates a lifetime permanent rare
earth magnet and is operated directly from an alternating
current line through Eriez 30Hz control.
In the Hi-Vi method, the spring-mounted mass is
alternately both attracted and repelled by an AC
electromagnet assisted by the springs.
Intermeshing a fixed polarity permanent magnet with
an alternating polarity AC electromagnet eliminates the
rectifier since you would have an alternating attracting
and repelling force as the polarity of the electromagnet
alternated.
It will be noted that the pole pieces of the permanent
magnet are intermeshed in the air gaps of an
electromagnet. The polarity of the permanent magnet
is fixed; the polarity of the electromagnet alternates at
the line frequency. We have shown the polarity of the
electromagnet as it would exist on one side of the sine
wave. Note that both poles of the permanent magnet are
being attracted toward the unlike electromagnet poles.
They are also being repelled in the same direction by
the like electromagnet poles. This results in four forces
accumulating to drive the armature in the same direction.
It also results in closing the magnetic circuit through the
electromagnet providing a magnetizing effect on the
permanent magnet on each side of the sine wave. The
demagnetizing force is very minor for the attracting force
and the magnetic lines of flux would much prefer to be
attracted than repelled. This always tends to place the
permanent magnet in a magnetizing circuit regardless of
where the AC current is on the sine wave. As the polarity
of the electromagnet changes, all of the forces are
reversed and the permanent magnet armature is driven
in the opposite direction.
Varying and unstable line frequency has a diverse effect
on vibratory feeders because they are tuned mechanical
devices, designed for 30 cycle operating frequency.
Shifts in the operating point due to changes in frequency,
(greater than 31 Hz or less than 29 Hz) can cause higher
than normal spring stress, striking and high line currents
which can cause drive and tray failure. When operating
from portable engine-driven power plants, be certain that
the engine is up to speed and all other loads are started
and at running speed before starting the electromagnet
feeder.
The feeder should always be stopped first when the
engine-driven power plant is shut down.
CAUTION
Operation from portable engine driven
power plants.
N
S
N
N
S
AC
POWER
SUPPLY
POTENTIOMETER
ELECTRO-MAGNET
ARMATURE CONNECTED
TO SPRINGS AND
MOVING MASS
PERMANENT
MAGNET
Figure 10
Repairs
(cont.)
