Hi -
I'm an architect and structural engineer but very new to electrical and electronics - been reading a lot and hoping to learn more.
The project...
I've designed and built a custom staircase for a limited space situation in an aircraft hangar - to access the second floor loft area. The requirement was to not take up any of the first floor space. So, the staircase hinges at the first landing and the lower section (14 step strait run) is pulled up and down using a rope/pully system from the lower floor so it completely disappears against the ceiling when not in use.
The staircase has it's weight offset by a set of heavy duty springs (from a garage door) so there's very little weight to lift/lower. I haven't put a strain guage on it yet but I'd guess it's the equivalent of a 20-30 lb lift.
The goal...
I'd like to automate this raising and lowering of the staircase using an electric motor, wall switch (up/down/stop), with upper and lower limits to turn off the motor automatically when the stairs reach the floor when lowered and reach the ceiling when raised. So, I guess I'm looking to build something very similar to a garage door opener for the staircase.
So far, I've fashioned a spare 1hp 110v AC motor to a sprocket and hooked it to the stairs using aircraft cable. When I plug the motor in, it lifts the stairs quitely, evenly, and at a nice speed.
So - can anyone help a newbie with an A/C motor control circuit to make a 1 hp motor go forward, backward, stop, and automatically stop when it reaches it's upper and lower limits? I'd prefer the limits to be "felt" by the motor instead of having actual switches mounted to the stairs - meaning have the motor shut off when the weight of the stairs is supported by the floor (lower limit), and also shut off when the resistance of the stairs against the ceiling is felt (so the motor pulls the stairs snug against the ceiling but doesn't try to yank it through...). Again, similar to a garage door opener. I suppose these limits could also be programmed using an encoder as well. Anyway - thanks in advance for any ideas or suggestions.
I'm an architect and structural engineer but very new to electrical and electronics - been reading a lot and hoping to learn more.
The project...
I've designed and built a custom staircase for a limited space situation in an aircraft hangar - to access the second floor loft area. The requirement was to not take up any of the first floor space. So, the staircase hinges at the first landing and the lower section (14 step strait run) is pulled up and down using a rope/pully system from the lower floor so it completely disappears against the ceiling when not in use.
The staircase has it's weight offset by a set of heavy duty springs (from a garage door) so there's very little weight to lift/lower. I haven't put a strain guage on it yet but I'd guess it's the equivalent of a 20-30 lb lift.
The goal...
I'd like to automate this raising and lowering of the staircase using an electric motor, wall switch (up/down/stop), with upper and lower limits to turn off the motor automatically when the stairs reach the floor when lowered and reach the ceiling when raised. So, I guess I'm looking to build something very similar to a garage door opener for the staircase.
So far, I've fashioned a spare 1hp 110v AC motor to a sprocket and hooked it to the stairs using aircraft cable. When I plug the motor in, it lifts the stairs quitely, evenly, and at a nice speed.
So - can anyone help a newbie with an A/C motor control circuit to make a 1 hp motor go forward, backward, stop, and automatically stop when it reaches it's upper and lower limits? I'd prefer the limits to be "felt" by the motor instead of having actual switches mounted to the stairs - meaning have the motor shut off when the weight of the stairs is supported by the floor (lower limit), and also shut off when the resistance of the stairs against the ceiling is felt (so the motor pulls the stairs snug against the ceiling but doesn't try to yank it through...). Again, similar to a garage door opener. I suppose these limits could also be programmed using an encoder as well. Anyway - thanks in advance for any ideas or suggestions.