RE: (ET) Re: new electrics

["Pieter Litchfield" <plitch attglobal net>]

The motors do already have a thermal overload trip, although this is
probably more effective for continuous high grass for a period of time
rather than a single big object.  Almost all "brush hogs" incorporate a
v-belt just because it protects the engine from the shocks of sudden stops.
My big Gravely brush hog uses a disc clutch  in the driveline which will
slip.

The ET did not have any belts because, I suspect that the whole idea was to
get away from belts (which drove regular lawn tractor operators crazy).  I
suspect that there is a relationship between the size of the motor, the
speed of the motor, and the length of the blade.  The ET mower motors could
not swing a much bigger blade without losing a lot of speed in heavy grass.

A possible advantage of belts - my Dad had a riding mower (Jacobsen?) that
used a toothed belt and pulleys to keep the two blades "in synch" - the ET
could use two bigger blades providing they were "in synch" so the tips 
could
overlap.  However, the mower motor would have to be substantially bigger to
swing two big blades.

-----Original Message-----
From: elec-trak-bounces cosmos phy tufts edu
[mailto:elec-trak-bounces cosmos phy tufts edu]On Behalf Of welches
Sent: Thursday, February 19, 2004 12:55 PM
To: elec-trak cosmos phy tufts edu
Subject: (ET) Re: new electrics


Regarding belts & immovable objects...  One of the appeals of the ET is 
that
there aren't any complicated belt mechanisms, especially with a mid-mounted
deck where access is tight.  To avoid losing a motor, why not have an
"overload" breaker switch of some sort that cuts out when a blade is
forcibly stopped or highly stressed?  The operator could just reset it and
proceed.  No belts to change, no safety issues, no fuss...

My 2 cents - and I don't even own an ET yet!  How's that for cheek!

Steve


_______________________________________________
Elec-trak mailing list
Elec-trak cosmos phy tufts edu
https://cosmos.phy.tufts.edu/mailman/listinfo/elec-trak