Re: Central Vac overload

["Robert Green" <robert_green1963@xxxxxxxxx>]

"Art Todesco" <actodesco@xxxxxxxxx> wrote in message
news:hp23vs$278$1@xxxxxxxxxxxxxxxxxxxx
> On 4/1/2010 8:18 AM, Josepi wrote:
> > Read the rest of the comments. This is a moronic device for a self
protected
> > motor / fan system.
> >
> > No air movement = higher motor speed = less work being done = less
stress on
> > motor = less current draw
> >
> >
> Ya but .... In the central vac unit the
> air flow over or through the motor is
> what cools the motor.  The "moronic
> device"

Certainly not in my mind and I'm the OP.

> would solve that problem by
> providing an inlet for air, when the
> lines are plugged.  I'm not sure I agree
> with the vendor's picture of the house
> and garage burning down.  The motor
> thermal protector should prevent that.

Yes, the fire was a little much, but it almost never hurts to have an extra
layer of protection, especially against catastrophic outcomes.

> That all said, I had a central vac in my
> previous house for 36 years and can
> count on one hand the number of times
> the thing actually plugged up.  Robert,
> if it is plugging in the hose, there
> might be something wrong in the hose
> causing it, like a tear which would
> catch fuzz going by.  If the plug is
> occurring in the wall piping, again
> there might be a reason.  I remember my
> 2 year old dumping some small wooden
> blocks in the inlet near his room.  They
> went through the pipe with no problem
> but couldn't make it through a Tee.  It
> was about 1" x 1" x 3".  This caused a
> place for new dirt to catch and
> eventually plug up.

You've hit on the problem.  A dog that loves to tear pieces of rag and
nylabone just large enough to catch on a crimped section of the hose.

When I tested the output of the unit's exhaust port with the hose blocked, I
noticed that although the exhaust flow cfm's dropped dramatically, the feel
of heat on my hand increased appreciably.

That was clear evidence that the motor depends on good hose airflow for
cooling and to let it run clogged was risking heating the bearing lube until
it evaporated and possibly burning the insulation on the motor windings.
Only a moron would expose an expensive motor system to unnecessary stress if
there was a ten dollar way around it.

I would rather notice lack of suction from a bypass opening than from a clog
that was burning up the motor.  One wastes maybe 1 minute of extra
electricity and the other subjects a motor to 1 minute of unnecessary
stress, resulting in who knows how much shorter a life.  That's a no
brainer.

--
Bobby G.