A debate has started at one of our local woodworking stores which
someone may be able to help with. Ques: when the intake of a shop
vacuum(or any vacuum for that matter) becomes stopped up and the motor
begins a much higher pitched sound, what has happened? Is the motor all
of a sudden under a much higher load which causes the change or is it
because the fan is all of a sudden starved for air and the motor is
under no load at all and races to a much higher RPM which causes the
higher pitch? In either case is the motor likely to fail/burn up/etc if
nothing is done to unstop the intake?
Thanks for your inputs-
cduke
In article <[email protected]>,
Carlton Duke <[email protected]> wrote:
>A debate has started at one of our local woodworking stores which
>someone may be able to help with. Ques: when the intake of a shop
>vacuum(or any vacuum for that matter) becomes stopped up and the motor
>begins a much higher pitched sound, what has happened? Is the motor all
>of a sudden under a much higher load which causes the change or is it
>because the fan is all of a sudden starved for air and the motor is
>under no load at all and races to a much higher RPM which causes the
>higher pitch? In either case is the motor likely to fail/burn up/etc if
>nothing is done to unstop the intake?
>Thanks for your inputs-
>cduke
The "mechanics" of what is going on depends _greatly_ on the design of the
particular unit.
Some types speed up because they do -not- have as much of a load of air to
push against. It's not "no load at all", but a 'lower load'.
Other types have to 'work harder', because of the increased partial vacuum
they're working against.
In _either_ situation, the unit *IS* likely to fail/burn up/etc. if left
in that condition for an extended period. Almost all units use the
airflow to cool the motor. Stop the airflow, and the motor *will* overheat.
Which leads to disastrous results.
Without air moving through the unit, the motor will overheat very quickly.
Dave
Carlton Duke wrote:
> A debate has started at one of our local woodworking stores which
> someone may be able to help with. Ques: when the intake of a shop
> vacuum(or any vacuum for that matter) becomes stopped up and the motor
> begins a much higher pitched sound, what has happened? Is the motor all
> of a sudden under a much higher load which causes the change or is it
> because the fan is all of a sudden starved for air and the motor is
> under no load at all and races to a much higher RPM which causes the
> higher pitch? In either case is the motor likely to fail/burn up/etc if
> nothing is done to unstop the intake?
> Thanks for your inputs-
> cduke
On Sun, 20 Mar 2005 19:58:45 -0500, Carlton Duke
<[email protected]> wrote:
>A debate has started at one of our local woodworking stores which
>someone may be able to help with. Ques: when the intake of a shop
>vacuum(or any vacuum for that matter) becomes stopped up and the motor
>begins a much higher pitched sound, what has happened? Is the motor all
>of a sudden under a much higher load which causes the change or is it
>because the fan is all of a sudden starved for air and the motor is
>under no load at all and races to a much higher RPM which causes the
>higher pitch? In either case is the motor likely to fail/burn up/etc if
>nothing is done to unstop the intake?
>Thanks for your inputs-
>cduke
the motor is under no load. the RPMs go up and the cooling airflow
goes away. the motor will get hot and likely overheat if left running.