Ship Repair Railway
· Stamp-Controlled Ship Repair Railway
·
·· Marine Railway Controller
·· This marine railway is designed to haul up ships up to about 1900 Tons dead weight. The system is essentially a large railway flatcar moved by a very heavy-duty winch. Before the Stamp system was put in, the winch was powered by a specially built 120 HP electric motor. The motor and some of the intermediate gearing had been damaged beyond repair and a hydraulic system was proposed.
· The new system used two Isuzu marine diesels rated at about 100 HP each. They drove variable displacement hydraulic pumps and the electric motor was replaced by a hydraulic multi-piston planetary drive motor. Torque and speed characteristics of the hydraulic drive allowed bypassing of the damaged gearing. Control of the pumps was by a proportionally controlled valve which was controlled through a MOSFET by the PWM command in the Stamp. Even though the PWM command doesn't generate a traditional PWM pulse stream, the response of the valve was such that it filtered the signal to give a very usable control profile. The valve signal is reversed with a set of relays connected as a DPDT switch to give operation in the opposite direction.
The source code and pics are attached.
· The operator stand was provided with a 2 x 16 LCD display which shows the speed of the rail car, the control push buttons which increase or decrease the speed, an emergency stop button and a key switch. The Stamp BS2 is mounted in the operator console on a standard circuit board developed by the writer and is powered off the diesel's battery so it can be used during power interruptions.
· The system was well received by the operators chiefly due to the fine degree of control provided compared to the old electric motor setup. With the diesels, the operator starts them, sets their speed then does all raising and lowering of the car with the Stamp. The control provided by the Stamp and the stall torque generated by the hydraulic motor enable full loads to literally be moved at a snail's pace all the way up to a fast walk. For smaller ships, the system will run on a single diesel.
·
·· Marine Railway Controller
·· This marine railway is designed to haul up ships up to about 1900 Tons dead weight. The system is essentially a large railway flatcar moved by a very heavy-duty winch. Before the Stamp system was put in, the winch was powered by a specially built 120 HP electric motor. The motor and some of the intermediate gearing had been damaged beyond repair and a hydraulic system was proposed.
· The new system used two Isuzu marine diesels rated at about 100 HP each. They drove variable displacement hydraulic pumps and the electric motor was replaced by a hydraulic multi-piston planetary drive motor. Torque and speed characteristics of the hydraulic drive allowed bypassing of the damaged gearing. Control of the pumps was by a proportionally controlled valve which was controlled through a MOSFET by the PWM command in the Stamp. Even though the PWM command doesn't generate a traditional PWM pulse stream, the response of the valve was such that it filtered the signal to give a very usable control profile. The valve signal is reversed with a set of relays connected as a DPDT switch to give operation in the opposite direction.
The source code and pics are attached.
· The operator stand was provided with a 2 x 16 LCD display which shows the speed of the rail car, the control push buttons which increase or decrease the speed, an emergency stop button and a key switch. The Stamp BS2 is mounted in the operator console on a standard circuit board developed by the writer and is powered off the diesel's battery so it can be used during power interruptions.
· The system was well received by the operators chiefly due to the fine degree of control provided compared to the old electric motor setup. With the diesels, the operator starts them, sets their speed then does all raising and lowering of the car with the Stamp. The control provided by the Stamp and the stall torque generated by the hydraulic motor enable full loads to literally be moved at a snail's pace all the way up to a fast walk. For smaller ships, the system will run on a single diesel.
Comments
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Chris Savage
Parallax Tech Support
csavage@parallax.com
Yes, the display is under the plexiglas which is glued on with silicone. The building is unheated (except when both engines are really working!), but it does have a roof, so weather-tightness wasn't a big issue.
When I need a certified enclosure (such as NEMA) I buy the standard box with the plexiglas factory installed. The display is just mounted on standoffs inside so it can be seen through the window.
Cheers,
Tom Sisk
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engineer, fireman, bowler, father, WoW addict [noparse];)[/noparse]
The valve is actually integrated into the pump. It does, of course, have both electronic and hydraulic feedback circuits. However, the signal required from the Stamp is a bi-polar 4 - 20 mA signal proprtional to the "desired" operating point. Getting to that point is done inside the pump unit.
If you're familiar with mobile equipment hydraulics, its very similar to a John Deere/Hyundai excavator control where the pump stroke ( ie output ) is regulated by a low voltage pressure transducer in the hydraulic header.
Tom
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engineer, fireman, bowler, father, WoW addict [noparse];)[/noparse]