Re: Need speed switch for DIY funicular/hillside elevator

[astutesolutions@xxxxxxxxxxxxx]

My thoughts...

Dave Houston wrote:

> I think what you want is something which loads the shaft in proprtion to the
> speed so that at normal climbing speed there would be minimal load while at
> the higher speed of a runaway, it would create a maximum load, slowing the
> descent. It may prove that an air compressor is inadequate but I think you
> understand the general idea.
>
> I do not like any of the friction-based suggestions. I think they present
> maintenance problems and will, themselves, be prone to catastrophic failure.
> You want something that requires little maintenance and is fundamentally
> failsafe.

Although I think the speed governor with a brake pad on a fixed cable
would be the better solution in terms of noise and reliability, it
would be harder to implement than a direct drive to an air compressor.
But the AC would be noisy (pap-pap-pap-hssss).  Either would require
periodic maintenance I suppose.

>
> Also, I don't like anything that's passenger operated since it might carry
> someone unfamiliar with its operation.
>

Agreed.

> I really have no idea how big an electric motor needs to be to act as a
> brake when it is generating electricity into a resistive load (as shown in
> the first link I cited) but, individual motors on the wheels of the tramcar
> might be another possibility.

That would require a battery to energize the stator (I think) and I
don't want to have any electronics (other than the remote) on the cart.
 Besides, those wheels took me the whole weekend to get right, I don't
want to touch them again if I can help it, lol.

Les wrote:
> Jeff,
>
> It does get a bit challenging does it not.  Diverting from the simple a bit
> you could consider this.
>
> Since you have already made the wireless for control of the unit could you
> then incorporate a solenoid on the deadman switch that would override the
> foot pedal for a one-time trip.  This could be set up in relay logic that
> would respond off a momentary push button at either end.  Once the tram
> reached its new position it would trip a limit switch and return all
> functions to normal.  It would require that some power on the tram but this
> could be accomplished with a battery with some indicator when the battery
> gets low.

Yes, that is a bit more complex.  I would have to have a battery on
there and keep it charged which would pose its own problems for
maintenance.

One whimsical solution, perhaps I should have a parachute pull a cotter
pin, lol.  If I could count on the wind not pulling it on a windy day.