Aquarium air pump motor

[bryan]

All:

Anybody know what type of motors are used in hobby aquarium air pumps. I am using a AC motor controller to control the speed of one. Wondering if this is the proper match for this type of motor. I did have a aquarium air pump once that had a rheostat/pot to control the motor.

 

[JimB]

When I kept fish, many years ago, the air pumps which I had used a vibrating type motor.

The "rotor" for want of a better word, operated against a torsion spring and would oscillate with a rotary motion (+/- 10 degrees or so).

I think that the spring/mass of the rotor was resonant at 50hz, so changing the frequency would probably not be very effective.
I guess something which changed the supply voltage would work.

JimB

 

[bryan]

JimB:

Yes, the AC motor controller I am using adjusts the voltage and it seems to work fine. I guess these motors are not really motors in the true sense, but more of a transformer.

 

[MrAl]

Hi,


The kind i had was also a vibrating type. It vibrated a diaphragm and with two check valves it was able to push air out the air hole. I dont remember the operating principle now though. It's similar to a relay that keeps opening and closing, with an arm like a relay that keeps moving back and forth.
I think it uses a coil to create a changing magnetic field that changes direction 60 times a second to keep in line with the power line frequency (or 50 times a second) where it pulls a magnet in closer on the positive half cycle and pushes it away on the negative half cycle (or vice versa). That magnet, mounted on a flexible hinge, is physically coupled to the rubber diaphragm. As the diaphragm moves outward (positive half cycle) it sucks in air through one check valve that is allowed to pass air from the outside of the case to the inside of the diaphragm, and as the diaphragm moves inward it pushes the air out through another check valve that is allowed to pass air from the inside of the diaphragm out through the outlet nozzle where the air then travels down the tube and into the filter. The repeated action of the magnet (and thus diaphragm) keeps an average air flow going, although without a small storage space it will be a pulsing air flow. The delivery tube itself may act as a small storage area so the pulsing may even out a bit before it gets to the filter.
If it is this kind, if you limit the voltage peaks on the two half cycles the motion of the magnet (and thus the diaphragm) will be more limited so the air flow rate will decrease.

 

[JimB]

Mr Al

Yes, that was the sort of thing, a diaphragm and a couple of check valves.

JimB

 

[PatM]

All:

Anybody know what type of motors are used in hobby aquarium air pumps. I am using a AC motor controller to control the speed of one. Wondering if this is the proper match for this type of motor. I did have a aquarium air pump once that had a rheostat/pot to control the motor.

I haven't had a aquarium for years but used both a vibrating type pump and a rotary motor/piston type in the past.
Instead of regulating the motor, I had a jar with bleed valve on the cap, which was in the supply line.
This acted as a filter/pressure regulator.
I ran the motors at full speed and regulated the amount of air coming out of the jar,by bleeding off some air to maintain the pressure available at the aquarium.
This does the same thing as varying the motor speed, which controls the amount of air in a different way.