:mellow:

 

Originally posted by rose ann arandia@May 14 2006, 06:30 PM
:mellow:

[post=17084]Quoted post[/post]​

Can you supply additional details describing how you would like this model elevator operates?

hgmjr

 

Originally posted by hgmjr@May 14 2006, 04:40 PM
Can you supply additional details describing how you would like this model elevator operates?

hgmjr

[post=17085]Quoted post[/post]​

it is a two storey elevator system.....runs by a motor,limitting switches and a simple circuit diagram......this is only my plan and honestly i dont know where to start this project.....so pls help me....thank in advance....

 

it is a two storey elevator system.....runs by a motor,limitting switches and a simple circuit diagram......this is only my plan and honestly i dont know where to start this project.....so pls help me....thank in advance....

 

Okay, just look at a full scale elevator...

You'll want limit switch for the upper floor lower floor to stop the motor. Additional switches for "close to limit" would be handy to slow the motor down. You'll want limit swithces for door open and door closed. You'll want a safety bumper switch on the door, and also an optical system to check for obstruction. You'll want a call button on each floor. You'll want a floor selection button for both floors. (Why they do that on a two story elevator, I'll never know. Tradtion, I guess.) You'll want buttons to hold the door open and to close the door. You'll want an alarm button and a telephone or intercom. If you want full authenticity, you'll want a key switch for lockout and over-ride.

You'll want logic that determines whether the motor moves, and in which direction. For full authenticity, you can add a fire alarm recall feature. You'll want logic for opening and closing the door.



...unelss, of course, it's just an old-fasioned freight elevator. Then you just need limit switches for each floor and direction control switch. I've been in one elevator where everything was done with one switch, a steel cable, and some clever mechanical bits. We pulled up on the steel cable to go down, down to go up, and the mechanical bits pulle the cable the other way when we got to where we wanted to be and threw a lever.

 

Originally posted by thingmaker3@May 14 2006, 06:33 PM
Okay, just look at a full scale elevator...

You'll want limit switch for the upper floor lower floor to stop the motor. Additional switches for "close to limit" would be handy to slow the motor down. You'll want limit swithces for door open and door closed. You'll want a safety bumper switch on the door, and also an optical system to check for obstruction. You'll want a call button on each floor. You'll want a floor selection button for both floors. (Why they do that on a two story elevator, I'll never know. Tradtion, I guess.) You'll want buttons to hold the door open and to close the door. You'll want an alarm button and a telephone or intercom. If you want full authenticity, you'll want a key switch for lockout and over-ride.

You'll want logic that determines whether the motor moves, and in which direction. For full authenticity, you can add a fire alarm recall feature. You'll want logic for opening and closing the door.
...unelss, of course, it's just an old-fasioned freight elevator. Then you just need limit switches for each floor and direction control switch. I've been in one elevator where everything was done with one switch, a steel cable, and some clever mechanical bits. We pulled up on the steel cable to go down, down to go up, and the mechanical bits pulle the cable the other way when we got to where we wanted to be and threw a lever.

[post=17098]Quoted post[/post]​

Exactly.....can you give me all the name of materials needed in this project....pls....thanks a lot......

 

hi all
my project is to build an elevator and control it using DC motors, a do not start in my project particullary, but i can tell you that yon need motors, sensors (infrared sensors or other on the door, and position sensors to stop the car on the level of the floor).
i will ask you if you need to control its speed smothly or not, and use stepper mptors or seperately excixited motors>>>>>>thanks

 

If you want to use relays, you can use the solution I've proposed in the other topic. Just take out the middle floor limit switch and presto. See the image below:
View attachment 1611
You can therefore rename the the UP and DOWN buttons to 1 and 0, respectively. The UP button will be the call button on floor 1 and the DOWN button will be the call button on floor 0. You can use this buttons inside the elevator car as well. You can even use two call buttons and two car buttons: just add more buttons in parallel with the existing ones.

I think I gave you enough info.

Note: If you can find two quad pole, double trow relays, use them. The alternative is to use four DPDT relays.

 

While a stepper motor might work for a toy or model, it is not an accurate representation of what is used in a real elevator. If the purpose of the project is to model a real elevator, then either solenoid controlled gearing or PWM should be used for speed control.

 

how big is your elevator, how much weight do it need to carry?

 

Okay, just look at a full scale elevator...

You'll want limit switch for the upper floor lower floor to stop the motor. Additional switches for "close to limit" would be handy to slow the motor down...

You don't need to adjust speed if the problem is faulty landing (the old "watch the step" problem). You can use a electric break to make the motor stop quickly. That is done by shorting the motor terminals after the current is switched off. This would be a simpler and cheaper solution and requires just the same number and type of relays I recommended in my suggestion.

 

You don't need to adjust speed if the problem is faulty landing (the old "watch the step" problem). You can use a electric break to make the motor stop quickly. That is done by shorting the motor terminals after the current is switched off. This would be a simpler and cheaper solution and requires just the same number and type of relays I recommended in my suggestion.

True, but the relay contacts would take a while to break/make. In the meantime, quite a large voltage spike would build up across the now-open contacts due to the inductance of the motor. A non-polarized capacitor across the motor terminals would help to blunt this spike; the size of which is TBD.

Too small = large spike; may exceed voltage rating of cap = destroyed cap.
Too large = excessive current draw on motor start.

 

True, but the relay contacts would take a while to break/make. In the meantime, quite a large voltage spike would build up across the now-open contacts due to the inductance of the motor. A non-polarized capacitor across the motor terminals would help to blunt this spike; the size of which is TBD.

Too small = large spike; may exceed voltage rating of cap = destroyed cap.
Too large = excessive current draw on motor start.

Indeed, you got a point. But most common relays have double trow contacts, which means that the same contact can be used to turn on the motor and to short the motor.

I think the capacitor will make the problem more severe. I'm assuming that you use a capacitor across the motor terminals. So when you short the motor and capacitor, you will short the current generated by the motor and the current generated by the capacitor. I think you are seeing the motor as an inductor, hence your worries about back emf in the form of high voltage spikes. The problem here are high current spikes. The motor here works just like a capacitor (generating a current with a decreasing voltage while it is stopping - think it as a momentum capacitor), and the currents will sum instead of subtracting to each other.

 

hey guys.. how about if i have to make a 4-storey elevator using dc motors,,
can anybody help me?

 

Let's keep the 4-story elevator in one thread: http://forum.allaboutcircuits.com/showthread.php?t=9781

I'm locking this old thread.