A
Rotary Position Transducer
attached to the gear motor output shaft provides the
position of the door. As the door changes position, the output signal from the
transducer varies in value. This signal, once converted to a digital value, is stored in the
CPU for further processing. This devise does not need to be “homed” or reset if there is
a power loss or electrical noise nor does it need to go through “learn speed” after power
up or after adjustments have been made.
Motor Control:
The
NB-4120 Bi-Parting Door Operator
uses a state of the art adjustable frequency
AC drive for variable speed control of the 230 volt, 3 phase, and 2hp AC motor. The
NB-4120 also features a multi-speed board that attaches to the side of the motor
control. The multi-speed board features control of (4) independent speeds. The NB-
4120 has the flexibility of controlling separate latch check speeds (Preset 1) and back
check speeds (Preset 2) as well as close speeds (Preset 3) and open speeds (Preset
4). The motor control also features additional trimpots, which greatly improve the
performance of the drive and motion profile of such heavy doors. The COMP (Slip
Compensation) trimpot sets the amount of Volts/Hz to maintain set motor speed under
varying loads. To increase, rotate clockwise. The ACC (Acceleration) trimpot sets the
amount of time for the motor to accelerate from zero to full speed. To increase
acceleration time, rotate clockwise. The DEC/B (Deceleration) trimpot sets the amount
of time to decelerate from full speed to zero speed. To increase deceleration time,
rotate clockwise. The MIN (Minimum Speed) trimpot sets the minimum motor speed. To
increase the minimum speed, rotate clockwise. The MAX (Maximum Speed) trimpot
sets the maximum motor speed. To increase the maximum speed, rotate clockwise.
Overload Protection
for the 3-Phase AC motor is provided by using (1) circuit breaker
for each phase from the 208/230 VAC 3-Phase power supply and the Adjustable
frequency AC drive (see wiring diagram). Additional protection is provided for
mechanical components by properly setting the Current Limit (CL) trimpot. This trimpot
also limits the Maximum Horizontal Operating Force (lbs) in both the opening and
closing directions. To increase, rotate clockwise.
Drive Train:
The
NB-4120
is a linear drive system comprised of a 2” wide XH polyurethane steel reinforced
timing belt driven by a 3 phase, 2 hp, 1750 RPM, AC motor that is coupled to an in-line helical
(85:1) gear reducer with an output torque rating of 7260 lb-in and overhang load rating of 2050
lbs. The timing belt is open-ended and is attached to the doors with matching aluminum
clamping plates. The belt is adjusted for pre-tension and tracking from the take-up end
frames. A properly installed and adjusted timing belt will provide operating forces up to 1400
lbs (total both doors) at the maximum speed of 6 in/sec (each leaf in opposite directions).
