A question about fan

EngineerAhmad

Hi every body..
Say you trapped the drag tube before a fan, what would happen then?
Will the Amber decrease?
Will the motor be heated ?
Why?

Please I need reasonable replies ..

Astronuc

It is not possible to give a reasonable reply without knowing more about the size of the drag tube, its orientation, the size of the fan.

What does one mean by trapping the tube before the fan?

What amber?

A motor would heat if there was more mechanical resistance to it. Most motors are designed for a particular speed.

EngineerAhmad

Say the fan is put in a tube which have the same size of it, then we trapped the tube before this fan, that no new air can be drawn.
Would the motor have less load (then the Amber of the fan motor will decrease) or the motor would be heated?
I.e: Would the load increase or decrease and why do everybody say the motor would break up?

negitron

Oh, I get it.

You can't really do this with an ordinary fan, since the enclosure which keeps you from accidentally contacting the blades allows enough space for air to circulate past. But, you can do this with a vacuum cleaner; if you put your hand over the intake, you can actually hear the result: the motor speed increases, since there is less drag on the impeller. In the meantime, however, the current draw (the word you want here is not "amber" it's "amperage) actually decreases. You don't want to run the motor for very long in this condition, though, because it is designed to be cooled by the airflow. Eventually the windings would overheat and fuse and the motor quits.