Federal APD PosiDRIVE, Installation, Operation And Maintenance Manual, Page: 15 / 96

PosiDRIVE Security Gate ZMA-330, Ver. 6 PosiDRIVE Structural Overview • 7
Figure 1.4
Enclosure Components
Mechanical Components
The PosiDRIVE gate is powered by a 150 watt, 24 VDC brushless DC gear motor.
The motor is connected directly to a fully sinusoidal four-bar drive mechanism. A
sinusoidal mechanism has the distinct advantage of providing smooth, progressive
acceleration and a mechanical advantage at the limits of travel, where it is needed most.
This arrangement eliminates the need for Vee-belts and their associated maintenance.
One advantage of a brushless DC motor is that the gate can adjust the speed of the entire
system depending on the size of the arm installed. Therefore, the same motor and
gearbox can be used in all situations, allowing the flexibility of using any size gate arm.
Another advantage to the brushless DC motor is the ability of the gate to know where
the gate arm is at all times. The motor provides an output that is monitored by the
controller. The controller interprets the signals to determine arm position and speed.
Using this information, the PosiDRIVE gate operates like a full servo system, providing
benefits such as not requiring mechanical contact to limit its travel, no limit switches,
and an extremely sensitive collision detect system.
The PosiDRIVE gate uses as many as four internal extension mainsprings to
counterbalance the weight of the gate arm. The number of mainsprings and their
adjustment must be properly set at the time of installation in order for the gate to
function properly. When correctly set, these mainsprings offset the torque on the
mechanism created by the weight of the arm, providing a safe, balanced system which
greatly reduces the power required by the motor and increases the efficiency of the gate.
Figure 1.5, on page 8 shows the PosiDRIVE mechanical components. Component
descriptions follow the illustration.
Enclosure Cap
Enclosure Base
Enclosure Door
Gate Arm