K7NV Prop Pitch Systems
Standard Control Box
This new control box was introduced at Dayton 2006.
This unit has several unique features that make it a very robust and reliable controller.
The FET used for pulse width modulation to control speed and start & stop ramps is self-protected.
It can't be blown by a short in the wiring or motor.
Other control boxes with unprotected FET's will run away out of control when the FET is blown because it fails closed.
There is an isolation relay that won't allow power to be applied to the motor until rotation is desired.
This prevents runaway rotation in the event of a short or wiring problem in the system.
The direction indicator uses a reed switch mounted on the prop pitch motor.
The pulse sensing circuit is very robust and does not lose calibration, even with long cable runs.
The controller has adjustable speeds and start/stop ramps.
The ramps can be adjusted from no ramp up to 25 degrees of ramp in 5 degree intervals.
The gear reduction ratio can be programmed to match the variety of different prop pitch gearboxes and those that have
been modified from their original ratio.
The controller has adjustable software limits and can be programmed for more than 360 degree rotation.
If there is a failure in the indicator pulse signal, the controller shuts off power and displays an error message.
This way it won't run without knowing the correct rotator azimuth.
The rotator can be turned manually with the CW/CCW buttons or with the “point And Shoot” knob.
With manual control, the starting ramp is controlled by the ramp variable that has been programmed.
No stop ramp is active in manual control. With the “Preset Knob” control, the desired heading is selected by turning the knob.
When the knob stops turning the rotator will automatically rotate to the heading with both start & stop ramps active.
This control box can be connected to the normal Green Heron RT-20 control box for other rotators for master/slave operation.
The controller uses 3 wires for the motor. Terminal #1 is the +dc lead to the clockwise motor terminal. Terminal #2 is the counterclockwise + dc motor lead. Terminal #6 is the motor common -dc lead.
10-12 gage wire is recommended for the motor leads. This control box will work with 10 gage wire up to a maximum cable run of 300 feet . Longer runs need to use larger wire or the remote power supply system. (See Below)
Terminals #3 & #4 are the connections for the indicator pulse leads. These can be small 18-22 gage wire.
Price includes the dynamically balanced magnetic spinner, mounting hardware and reed switch shown at bottom of this page. When controller is ordered with a K7NV prop pitch rotator or rebuild of customer unit, the spinner kit installation is included.
K7NV Prop Pitch Systems
Remote Power Supply Control System
Control Box for Operation from the Shack
Remote Control System with Power Supply
This control system was introduced at Dayton 2007.
It is specially built for K7NV Prop Pitch Systems by Green Heron Engineering.
This system has a control box, that is different from the Standard box, an existing RT-20 or RT-21 control box can be easily converted to run the remote system.
It has a remote power supply that is mounted in a weather proof enclosure that can be placed out at the tower.
This system was designed to allow the use of existing or new small rotator cable from the shack out to the remote box. Then, moderate size wire can be run to the rotator motor.
It allows for very long cable runs, and eliminates the need to use very large wire to reduce voltage drop at the rotator motor.
It has the same unique features as the standard control box which also makes it a very robust and reliable controller.
This control system can be connected to the normal Green Heron RT-20 control box for other rotators for master/slave operation.
The control box in the shack uses a 5 wire cable to control the remote system.
These wires can be #20-#22 and connect to terminals 3, 5, 6, 7, 8 on the control box,
and terminals 1, 2, 3, 4, 6 on the remote control board.
The remote system can be powered with either 115 or 230 vac.
The power supply produces either 28 or 32 vdc at 15 amps depending on how the transformer primary taps are connected.
Wire size for the AC power is #18.
A 3 wire cable is run from the remote box to the rotator motor.
This can be #12 or #14 depending on the length of the run.
A 2 wire cable run from the remote box to the rotator pulse switch mounted on the electric motor is required.
This can be #20.
The motor and pulse wires can be run in the same cable.
Price includes the dynamically balanced magnetic spinner, mounting hardware and reed switch shown below. When controller is ordered with a K7NV prop pitch rotator or rebuild of customer unit, the spinner kit installation is included.
Pulse Signal Kit
Both Control Systems use this Pulse Signal Kit to provide Direction Indication
Balanced Spinning Arm With Magnet & Pulse Switch Mounted on Small Motor