USB Nano Air Pump Teardown

[TheDukeAnumber1]

I've seen questions about the Co-op's nano air pump pop up often so here is a quick teardown of the usb nano air pump.

 

With half of the out rubber removed we can see two main components, the motor(right) and the pump(left).

 

On the bottom of the motor we can see a large 50-Ohm resistor between the terminals. I believe this resistor is there to protect the power supply. When the power is cut off the motor still spins for a moment and can throw some power back at the power supply, this resistor would help eat up that power.

 

On the pump end we find three small screws.

 

Once we remove the screws and top we find three small diaphragms that pump up and down when the motor runs.

 

 

Now with the diaphragm rubber removed we can see the motor head piece that moves the diaphragms and on the underside of the top we can see the three small rubber backflow valves. I guess those screws weren't so small after all.

 

And there we have it, the guts of the fabled pump popularized by our beloved Co-op.

 

Edited August 28, 2020 by TheDukeAnumber1
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[DaveSamsell]

@TheDukeAnumber1, Very interesting post.  From my vantage point I cannot discern the exact color code on the resistor.  

Have a question though:  Did you unsolder one leg of the resistor & then check the resistance of the component?  Otherwise, you may be reading a parallel resistance with the motor and not the true value of the resistor itself.  

Also, is one lead of the resistor 'tack soldered' to the motor housing?  Again, hard to tell from this viewing vantage point.  

[TheDukeAnumber1]

9 minutes ago, DaveSamsell said:

@TheDukeAnumber1, Very interesting post.  From my vantage point I cannot discern the exact color code on the resistor.  

Have a question though:  Did you unsolder one leg of the resistor & then check the resistance of the component?  Otherwise, you may be reading a parallel resistance with the motor and not the true value of the resistor itself.  

Also, is one lead of the resistor 'tack soldered' to the motor housing?  Again, hard to tell from this viewing vantage point.  

You're right, atm I wrongly thought the motor was isolated across the terminals. It's closer to 50-Ohms. I can confirm the resistor is not attached to the housing, it's only soldered across the terminals.

[DaveSamsell]

@TheDukeAnumber1, Yeah, isolating components, then measuring their  "unpowered" resistance value is the most accurate, safest approach, in this situation..  

I was tinkering around this morning and slipped off the green rubber boot on one of my pumps.

The resistor color code on mine was:

Green, Brown, Black & Gold

Green=5,    Brown=1,   Black=0,     and the Gold "tolerance" value represents 5 % tolerance value rating of the resistor component resistance itself.  So, 51 ohms @ +\-  5% tolerance.

The part # on my motor was  11670N - 180514

The resistance reading just across the motor alone was 33.4 Ohms

So, the two resistances "in parrallel" with each other measured 20.18 Ohms, which was close to your original measurement with everything connected together.

Note: These are D.C.resistance values, not to be confused with A.C. Ohmic impedance values, I.E. Audio speakers or other A.C. driven devices.

Since it's a basic D.C. motor, it simplifies things.

There are multiple reasons for the resistor including to protect the motor a bit if the power is often applied & removed.  It also changes the total circuit current (Amperage) consumption.

 

 

 

 

[Pete]

Somehow one of the cords on my USB nano air pump got damaged, causing it to short and not work. Earlier this week, I was able to cut out the damaged section and splice the wires without much hassle. I'm so glad these are nicely made. It's a good feeling when you can repair something vs throwing it away.

[DaveSamsell]

1 hour ago, Pete said:

Somehow one of the cords on my USB nano air pump got damaged, causing it to short and not work. Earlier this week, I was able to cut out the damaged section and splice the wires without much hassle. I'm so glad these are nicely made. It's a good feeling when you can repair something vs throwing it away.

 

@Pete, I purposely cut my power cord and soldered in a rotary thumb-wheel switch for an easy, on/off feature.

 

[pedrofisk]

1 hour ago, DaveSamsell said:

 

@Pete, I purposely cut my power cord and soldered in a rotary thumb-wheel switch for an easy, on/off feature.

 

How retro! I can't remember the last time I saw one of those.

[Bill Smith]

The only wish I had about this pump was that the cord could be easily replaced. I've had a pump get ruined once or twice from water splash, and it's been a nightmare disentangling the cord to replace it. I shudder to think the headache I will have to endure when one of the pumps on my 6-up nano ponds goes out...

If it were a modular cord attachment this truly would be the best small air pump on the planet.

[DaveSamsell]

30 minutes ago, Bill Smith said:

The only wish I had about this pump was that the cord could be easily replaced. I've had a pump get ruined once or twice from water splash, and it's been a nightmare disentangling the cord to replace it. I shudder to think the headache I will have to endure when one of the pumps on my 6-up nano ponds goes out...

If it were a modular cord attachment this truly would be the best small air pump on the planet.

Bill, 

That's a good idea.

Maybe @Cory will take your suggestion under advisement for future product revisions.