The reversing drum switches are particularly suited for use in manual reversing control applications
such as machine tools, woodworking machines, and similar types of equipment. Examples include
lathes, milling machines, planers, grinders, shapers, and boring mills. Other possible applications
include door operators, small hoists, and conveyor belts.
Overload and low-voltage protection are not incorporated into these reversing drum switches. Should
the power fail, the contacts will remain closed unless assembled for momentary operation, and the
handle will stay in the selected position. The motor will restart when the power returns.
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Voltage 600 Vac Maximum
250 Vdc Maximum
Contact Mechanism Large movable contact segments are rigidly attached to the main
operating shaft. They are fully insulated from each other and from the
shaft. Stationary contact fingers are mounted in polymeric blocks.
Both movable and stationary contacts are plated for maximum life.
Easily accessible terminals are provided to simplify wiring. Type A is
provided with screw-type terminals and Type B is provided with
pressure-wire connector terminals. Contacts are not replaceable.
Operating Mechanism The operating mechanism is factory assembled for Maintained
Position operation. That is, when the handle is moved to the forward
or reverse position, it will remain there until moved. The mechanism
can easily be converted to provide Spring-Return-to-Off operation,
with no additional parts needed. This conversion is accomplished by
removing the handle screw and handle, turning the shaft 180 degrees,
and then replacing the handle and handle screw.
Handles Both the NEMA 1 and NEMA 4 devices come standard with a onepiece molded handle.
Enclosures The polymeric NEMA 1 enclosure is suitable for indoor applications
when normal atmospheric conditions prevail. The NEMA 4 enclosure
is suitable for applications requiring watertight and dusttight
capabilities. Generous wiring space is provided in both types. Two
knockouts or openings for 1/2 in. conduit entries are located in the
bottom plate of Types AG and BG, while two 1/2 in. conduit entries
with hubs come standard on Types AW and BW.
A single captive screw holds the cover on NEMA 1 enclosures, while
three captive screws hold the cover on NEMA 4 enclosures.
Removing the cover allows free access to three sides of the switch
mechanism. Large, legible nameplates are securely attached to the
enclosures to clearly indicate switching positions and to provide
complete rating information. An instruction sheet showing typical
motor connections is also included.
