Alt-BEAM Archive
Message #05246
To: beam@sgiblab.sgi.com
From: Steven Bolt sbolt@xs4all.nl
Date: Sun, 11 Jul 1999 06:53:23 +0200 (CEST)
Subject: [alt-beam] Re: Something funny with the 1382 voltage triggers?
On Sat, 10 Jul 1999, Bob Shannon wrote:
> > I see no advantage of shortening the motor burst when under heavier
> > loads, which is all your present setup does. The monostable would
> > exert extra effort when under heavier load - which seems
> > advantageous to me.
>
> Ahh, of course. Your photovores are not covering rough terrain!
Rough tiled floor, with rather wide and deep joints. Stops any
direct drive.
> Its better to shorten the steps when going up hill.
When using an SE which switches on at one voltage level, and off at
a lower voltage - both fixed - power consumption and dissipation
stay the same no matter what you do. Only the way power is
dissipated changes a little. When the load gets heavier, as in
rough terrain, the voltage drops faster and the motor becomes less
efficient. So less power serves the mechanical effort, before
dissipating.
The monostable SE keeps the discharge time constant, allowing the
motor to further discharge the storage cap when the going gets
difficult. You notice this immediately, because more time is needed
for the recharge - with a fixed voltage switch-off, charging time
depends only on the available light, not on the roughness of the
terrain.
In the monostable design, the storage cap has excess capacity, so
the voltage drop is normally only 0.1V or so. Extra effort may
cause a few tenths of a volt extra drop, no more. So the drop
becomes neither too deep nor too fast. Your motor always receives
the kind of fairly constant power it likes best.
Best,
Steve
----------------------------------------------------------------------
# sbolt@xs4all.nl # Steven Bolt # popular science monthly KIJK #
----------------------------------------------------------------------
------------------------------------------------------------------------
eGroups.com home: http://www.egroups.com/group/alt-beam
http://www.egroups.com
- Simplifying group communications
Home