On Jun 16, 6:15*am, Laurav wrote:
On Jun 16, 12:57*am, wrote:

Can you supply any info on the motor itself? Not the current draw but
the type of motor?

He said it's a universal motor. *It has brushes.
It would be enough to control the input voltage, that's what I'm now
trying to do by hand. *I think if I were standing by the rheostat all
the time, I could control the motor speed well enough.
It's in a metal box, I don't know what's inside the box.
What Jamie seemed to be saying is that there's some kind of feedback
loop that might make the motor very voltage-sensitive, that he said
would apply to a fan motor. *This isn't a fan, it's an air turbine.
In any case, this is what I have, and what I'd like to get running
more evenly.
It's not like there are a huge variety of airline respirators on the
market. *I'm not sure if the very expensive NIOSH-certified ones have
more sophisticated motor control or not. *I somewhat doubt it - I
called one company and he said the innards were about the same for his
NIOSH-certified version vs the home use version.
These airline respirators are used by auto body workers or hobbyists,
sandblasters, etc. *Precise volume control might not be necessary for
them.

So it's OK if something designed to protect human life works like
crap? I'm not sure how they figured that that was OK.

The voltage at an outlet does seem to vary more than the utility co.
voltage, so I may have electrical problems that can be fixed and would
give more even airflow.
Laura

You said that the speed varied completely within a 20 VAC range --
100-120VAC -- that the input voltage was critical to fan speed.
Turbine Products did not design a product to cope with normal voltage
fluctuations, which can easily be +/-10%.

Is this UL approved? Is there some safety standard it's supposed to
comply with? Have you contacted NIOSH to tell them of your complaint?