Eriez’ unique Hi-Vi magnetic drive circuit provides a simple yet powerful solution to dif cult material feeding applications. These feeders, with their totally enclosed patented magnetic drive, can feed practically any bulk material from micron size to bulky chunks. Solid-state controls operate the feeders with “watch– like” precision. In addition, you get all the features that for years have made Eriez Feeders the leaders in quality and dependability. Eriez has standard models for the majority of feeding applications. Special units such as multiple drives, enclosed trays or screens can be designed for the best solution to your application. In addition, a wide variety of standard and special trays are available.
Electro–Permanent Magnetic Drive
The basic simplicity of a drive powered by alternately opposing and attracting magnetic forces assures low maintenance. There are no sliding or rotating parts. Power consumption is low, installation easy. The positive driving force of Eriez units provides stability, control, and unexcelled accuracy.
AC Operation For Most Models
No rectifiers are required; feeders are simply wired into AC lines.
Eriez electromagnetic feeder controls are reliable, state-of-the- art, solid-state units that deliver superior feed rate control. By varying the voltage to the feeder, coupled with Eriez AC circuit, excellent linearity is acheived. Standard controls come in NEMA 12 (IP54) enclosures. Special enclosures are also available. Controls can be provided with manual or automatic (analog signal) adjustment to address many applications. Special design controls are also available to address your unique requirements.
The coil and magnet in Eriez’ drive unit are encapsulated in epoxy, eliminating coil movement and thus extending trouble – free coil life.
Enclosed Drive Element
The completely enclosed drive element, dust and moisture resistant, extends coil life and makes external cleaning easier. Special enclosures are available for dusty locations where Class II, Group F and G equipment is normally used.
High Temperature Units
Standard units operate at temperatures up to 130°F (54°C). High–temperature units are available for temperatures up to 300°F (150°C).
The Patented Eriez Hi–Vi Magnetic Drive Circuit
Prior to Eriez revolutionary AC design, electromagnetic vibratory equipment operated with an inef cient attract release system: a spring – mounted moving mass is alternately attracted by a rectified pulsating DC electromagnet and returned to its original position solely by the springs. The Eriez HI-VI system, on the other hand, incorporates a lifetime permanent magnet (part of a spring–mounted moving mass) whose poles are intermeshed with those of an electromagnet powered directly by an AC line. This results in the spring- mounted moving mass being both attracted and repelled by the AC electromagnet equally on each half of the AC cycle.
In the diagram below, the poles of the permanent magnet are shown intermeshed in the air gaps of the AC electromagnet. The polarity of the permanent magnet is xed, while the polarity of the electromagnet alternates at line frequency. The electromagnet polarity is shown as it exists on one side of the AC sine wave; note that both poles of the permanent magnet are attracted toward the unlike electromagnet poles while being repelled in the same direction by the like poles. Thus there are four forces acting together to drive the armature and moving mass in the same direction.
The action described has the effect of progressively closing the magnetizing circuit through the electromagnet core, providing a progressively increasing magnetizing force upon the permanent magnet. The demagnetizing force is very minor, since the action described also has the effect of progressively opening the demagnetizing circuit.
On the opposite side of the sine wave the polarities of the electromagnet are reversed, the armature is driven in the opposite direction, and again there is a net magnetizing force on the permanent magnet. There is always a predominant magnetizing force impressed upon the permanent magnet that prevents it from ever losing its strength.
Since the amplitude of vibration depends directly upon the forces applied at the poles, and since these forces depend directly upon the applied AC voltage, simple variation of the AC voltage from zero to maximum results in similar amplitude variation from zero to maximum.