Tower elevator alarm system
An elevator within a tower, such as a wind tower, includes a traction or drum type hoist powered by an electric motor where the hoist provides the mechanism to cause the vertical ascent or descent of the elevator. An aspect of the invention is to allow the descent of the elevator to drive the electric motor arranged to act as a generator and provide regenerative braking as well as power to drive an alarm device or devices.
1. A tower, comprising:
an elevator cabin;
an electric motor coupled to the elevator cabin;
a sheave coupled to the electric motor;
a power source electrically coupled to said electric motor when operational so that power from the power source is selectively applied to the electric motor to cause the sheave to rotate relative to a suspension cable fixed to a structure of the tower, the sheave rotation operable to raise or lower the elevator cabin within the tower; and
an alarm device electrically coupled to said electric motor such that said electric motor is operable to power the alarm device during descent of said elevator cabin without the need for power from said power source;
wherein current generated by rotation of rotor or stator winding in said electric motor is used to provide electromotive braking of the elevator cabin.
2. The tower of claim 1 wherein the tower is a wind turbine tower.
3. The tower as recited in claim 1 , wherein the electric motor comprises a component of a hoist.
4. The tower as recited in claim 1 , further comprising an AC to DC converter electrically coupled between the electric motor and the alarm device to control voltage applied to the alarm device.
5. The tower as recited in claim 1 wherein the alarm device comprises a sound generating device.
6. The tower as recited in claim 1 wherein the alarm device comprises a light generating device.
7. The tower as recited in claim 1 comprising a manual brake that causes the elevator cabin to stop when applied and to descend when released.
8. An apparatus for providing power to an alarm device without the need for an extrinsic power supply, comprising:
a traction hoist mechanism comprising an electric generator coupled to a sheave such that rotation of said sheave causes an electrical output from said electric generator;
an elevator cabin adapted to couple to a suspension cable such that movement of said elevator cabin in a first direction causes rotation of said sheave; and,
an alarm device in electrical communication with said electric generator, said alarm device capable of generating an alarm responsive to said electrical output from said electric generator;
wherein current generated by rotation of rotor or stator winding in said electric generator is used to provide electromotive braking of the elevator cabin.
9. The apparatus as recited in claim 8 wherein the hoist comprises a fraction hoist.
10. The apparatus as recited in claim 8 wherein the first direction of the elevator cabin is a vertical descent.
11. The apparatus as recited in claim 8 wherein the alarm device comprises a sound generating device.
12. The apparatus as recited in claim 8 wherein the alarm device comprises a light generating device.
13. The apparatus as recited in claim 8 comprising a digital device coupled between the electric generator and the alarm device to selectively operate the alarm device.
14. A method for powering an alarm device, comprising:
releasing an elevator cabin to cause the elevator cabin to descend in a tower;
causing the elevator cabin to rotate a sheave that is frictionally coupled to a suspension cable; and
causing the sheave to rotate a motor such that the motor generates electrical power as a result of the rotation, the electrical power providing power to an alarm device;
wherein current generated by rotation of rotor or stator winding in said motor is used to provide electromotive braking of the elevator cabin.
15. The method for powering an alarm device as recited in claim 14 , further comprising:
coupling the elevator cabin to the suspension cable wherein the suspension cable is fixed to a structure of a vertical tower.
16. The method for powering an alarm device as recited in claim 14 wherein the motor is a component of a hoist.
17. The method as recited in claim 16 wherein the hoist is either a traction hoist or a drum hoist.
18. The method as recited in claim 14 wherein the alarm device generates a sound when power is applied to it.
19. The method as recited in claim 14 , wherein the motor generates an alternating current and wherein the current is converted to a direct current before applying the power to the alarm device.
20. The method as recited in claim 14 wherein the step of releasing the elevator cabin comprises releasing a manual break.