Need to drain off curent.

[Alec_t]

If the brakes are released and the motors are open-circuit, will the elevator move down under the weight of a full load, or is friction enough to keep it stationary?

 

[BobK]

And do remember, something has to heat up if you are slowing the elevator via generated voltage. (Just as it would with a mechanical brake)

Bob

 

[Terry01]

Check out "wheelchairdriver.com" web site buddy. I'm a wheelchair user myself. Its relatively easy to sort this but the guys there will guide you much better than I will. Just don't let them convince you to "go lithium"! Lol
Good luck with your project.

 

[73's de Edd]

Sir Jongig . . . . .


A continuance . . .

You said . . .
The reason I think the motors are the key is because if the motors are shorted the elevator going down barely moves so if the electricity is regulated the motors would maintain a certain speed.

My point of interest is the aspect of
if the motors are shorted the elevator going down barely moves.
So I take that as the platform will then move down from a dead stop at top . . . but slowly . . . with a shorting of the motor windings..

Lets now test by having the elevator platform at top and develop some operative parameters by having the DC motor wiring going to a positive and negative probe of a DVM with the probes shorted .
Then you release the short by separating the shorted probes to get the platform falling and you monitot the generator action of the moving motors and the rising level of voltage that they will develop.

Take note of the highest developed voltage by them when the plat is about 1/4 of the way down. Then short out the probes to engage braking to see how fast the electromagnetic field braking engages at that point and if and when a complete braking will occur..

Then get the plat back up to top and repeat but see the highest generated voltage at 1/2 way down and the same data and conditions at that position.

And then finally a like test at 3/4 down and those figures and time of braking engagement /effects.
With that info we now see the max open circuit voltage that those motors will create when acting as driven generators.(Particularly at that time involved in getting to that 3/4 down position.)

Then the solution seems to be a sampling of the voltage generated and dumping the excess voltage into an electronic load to thereby subject the motors to a variable loading, as being compared to generated voltage from the motors.

Or its variant where Sir Alec_t is using timely, variable pulse width shunting of the motors output.


73's de Edd