Once the battery is hooked up the motor is ready for the first test run. The magnets are stuck to the control arm with a small square of double sided tape. Many alligator clips are made from magnetic material so that's why the battery wires are connected directly to the brass hooks rather than making the connection with alligator clips (we don't want the powerful magnets jumping after the clips!). We then removed the hooks and poked the bare ends of the battery wires in the holes and once again screwed the hooks in to secure the wires in place. The pilot holes make it fairly simple to get the hooks screwed in at the right angle. It's best to first create pilot holes for the two hooks by forcing an awl tip or small phillips screwdriver tip into the wood with a twisting motion. To let the hooks comfortably cradle the wire axles of the armature, the hooks are screwed into the wooden base at about 60 degrees to the horizontal. The brass ceiling hooks become bearings, "brushes" and mechanical supports for the armature in this simple motor. brass is a pretty good electrical conductor.brass is a non-magnetic material so you don't have to worry about the strong neodymium magnetic jumping and attaching to the ceiling hooks.Solid brass was selected for this motor for two reasons: But steel and plated steel hooks are also available. Solid brass ceiling hooks are commonly available in hardware stores. The armature is also the electrical ON and OFF "switch" for the battery - it must be in place on the ceiling hooks for ON and completely removed for OFF. The armature coil, and coil ends serve as axles, bearings, and commutator. If this continues to be a problem remove a little more than half of the insulation from the axle. Therefore the armature coil might occasionally require a little bit of influence with your finger to get it going. When the armature coil is mounted on the brass ceiling hooks, current will flow through the coil only when the bare copper part of the "half-stripped" axle is in contact with the brass ceiling hook (the other axle is always in electrical contact with its hook). use the utility knife to "strip" the enamel insulation from both axles as demonstrated in the video and shown in the illustration here - be careful not to nick the wire during this procedure.Shift the wire axle wraps as needed to get a balanced feel. wrap 2 to 4 turns of the beginning and end of the wire tightly around the coil to keep the coil snugly together making sure that the resulting "axles" are directly opposite each other.wind the wire around the D cell leaving about 2 inches of wire on either end of the coil.string out and cut off about 6 feet of magnet wire from the spool.
Forward and reverse motor spool series#
This means that if the coil that drives the motor in the forward direction is energized, a normally closed set of contacts wired in series with the reverse coils will prevent that coil from being energized as long as the forward coil remains energized. To prevent unintentional energization of both the forward and reverse coil at the same time, the coils are equipped with normally closed contacts, which are then wired in series with the opposite direction’s coil to act as an electrical interlock. Reversal of three-phase motor rotationīoth coils power contacts feed through a single set of OLR to provide running protection in both directions. When the alternate coil is energized, Lines 1 and 3 are interchanged with Terminals 1 and 3, allowing for a phase shift in the 3-phase circuit, driving the motor and causing it to rotate in the opposite direction. They are connected so that under normal conditions, one coil will connect L1 with T1, L2 with T2, and 元 with T3. Motor Starters and Contactors 15 Forward/Reverse Starters NEMA Forward Reverse motor starter with OLRĪ forward/reverse magnetic motor starter is constructed from two regular contactors installed with a mechanical interlock that prevents both coils from pulling in simultaneously.
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