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DIY Harbor Freight Air Filter

There's your problem. You accepted an old repairman's tale. A dirty filter does not make the motor work harder. It make it work less hard, and decreases efficiency of your furnace because the fan is getting starved for air and doesn't heat the house as well. It costs more in electric bills because of efficiency loss not because the motor has to work harder, it has to work longer to get the same heating.
 
All motors are not designed exactly alike. Like in the case where the motor is designed to maintain a specific air flow. Air flow/pressure drops cause the motor to kick into overdrive, causing the exact issues I was describing.
You are applying this specific motor case and making general statements that are not always true for every motor design.
 
You say the motor doesn’t work harder... you also say it runs longer. Running longer is working harder. Do you call increasing run time working less hard?
You are also ignoring the fact that the motor needs to maintain a specific air flow to push the heated air through the ducting. Otherwise it would be only hearing your heater lol. Clogged filter = less air flow. If the motor is not hitting its set point, it could cause the motor to react and burn.
 
I'm commenting on basic electric motors, not ones with extra features like PID controller built in or winding taps. "Kicking into overdrive" when airflow dropped would require an airflow sensor. These are basically dumb devices made in China, not some premium USA made motor with a bunch of extra features.
 
Hmmm. I have personally worked on conveyors with USA and European made motors that had VFDs that were controlled by photo eyes, emergency stops, air flow sensors, temperature sensors, pressure sensors for many different applications. All currently used today in this country in modern day manufacturing lines.
Basic motor, as in a rotor and a stator? There is nothing basic about a motor, they are all designed with different features. Some are capable of operating on multiple voltages, some have overload protection (like your Chicago electric blower motor)., some have sensors. It all depends on what it’s designed to do.
 
No kidding. Motors are usually controlled by extra electronics, but that is not integral to the motor. You are beating this like a dead horse, for what purpose I have yet to determine. You can talk about automated machinery all you want, but I'm talking about a simple $50 blower made in China that might last a year or two if I'm lucky, regardless of my modification.
 
A Dead horse? But I was just talking to mr. ed...Now you say I killed him? Lol
Ok. Just reiterating that my cause for concern was justified. Some motors are designed to act exactly in the way I have described.
You are attempting to differentiate your blower’s motor from a motor controlled by other features. What did you think your overload protection was on the model you linked us all to? Do you think every motor comes equipped with that?
Failing to see the points of your last 2 posts. Maybe I am missing something here? Or maybe that horse’s corpse is in your back yard?
 
Toker1 commented
01-27-2020, 04:28 PM


And if that’s the case... the pressure causes the motor to spin faster than designed you get a current back flow. And your motor becomes a Generator creating amperage, burning up the components.

Not possible, a motor cannot generate power without an external source to drive the motor, there is no such thing as current back-flow.
 
Keep in mind vacuum cleaner motors are series wound and as you discovered will vary in speed, A/C motors are induction motors which are speed locked to the frequency of the power feeding them, as long as they are not overloaded they will not change speeds.

The only practical way to vary the speed of an induction motor is with a variable speed drive which is an A/C to A/C convertor which takes in standard 60 Hz power and can output various frequencies to vary the speed of the motor.
 
VFDs can be set up to convert DC to AC as well. I have seen plenty of 3 phase motors run on single phase power when a VFD is involved.
 
Incorrect, if the motor is DC reversing the polarity will reverse the direction of the motor, if the motor is designed for A/C nothing will happen as A/C in the US constantly reverses polarity hence the term Alternating Current.

You are also misreading what you posted a link to, in order for a D/C motor to become a generator, it, as I correctly stated, must be driven, this had been used for years for regenerative braking where the power to the motor is cut off and it is used to either charge batteries as in EV's or is dumped into resistor banks such as in locomotives utilizing dynamic braking.

Try getting an idea of what you are talking about before looking even more uninformed than you already are.
 
Well if it plugs into the wall it's A/C, Edison lost that battle with Westinghouse decades ago.

Maybe get a clue.
 
Says the guy who tried to claim there is no such thing as current back flow. I was just proving to you it does exist. I said I understood the mechanical external force. Speaking about bad looks, when you point fingers... there are 3 pointing right back at you. Try reading my remarks a bit more carefully if you want to react like a dick.
 
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Try engaging brain before opening mouth.

Here are the specs for that Harbor Freight blower.

Specifications

SKU(s)
61729, 93231, 69721
Brand
Central Machinery
AC Volts <<<<<<<<<<<<<<----------
120
Amperage (amps)
15
Flow rate
300 CFM
Material
ABS
Power cord (ft.)
8 ft.
Product Height
12 in.
Product Length
12 in.
Product Width
8-1/2 in.

Note the voltage spec A/C 120 volts, and I'll make it simple A/C = Alternating Current, which means the incoming power reverses polarity at a rate of 60 Hz.

Furthermore the motor in that motor unlike a vacuum motor is a shaded pole motor which is incapable of being used as a generator as it lacks either a permanent magnet rotor or a armature with a commutator.

You really need to do some studying up on motor /generator basics.
 
Once again I was not the one attempting to claim current back flow doesn’t exist. If I were to take advice, it would be from someone who actually knows something about this subject. Not some self righteous dick looking to put people down for learning. Come down off that high horse if you ever want to continue this discussion in a more civil manner. ✌️
 
My attitude comes with the experience I have working with industrial control systems and lots of motors, and when I see someone posting BS I will call them out on it. Don't like that then do some research and maybe a bit more understanding of motor technology before posting.
 
If you need to call someone out, check yourself. Current back flow does exist despite your claim. You like to act like you have all the experience, but a truly experienced individual would have known this. You can call me all the names you like, fact is you learned something new today. So all these shitty comments need to be applied to your own learning curve.
 
Reread what you linked to and you will discover you are incorrect counter EMF is absorbed and the motor does not turn into a generator unless driven .
 
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