The "Hitchhiker's Guide" to the Maxi-Stream mod

[zapata41]

umm, i dont think flipping it will do anything different but put a different leading edge for the prop, since the prop blades would hav eto be wrapped the opposite way they are tp be a right handed model.

damn i was so excited to get these octura props and none of them work on anything.

TIm

 

[hahnmeister]

Unlike the common AC powerheads that are cheap 2-pole configurations, the SEIOs prolly cost more and are a 3 or more likely a 4 pole configuration to ensure proper rotation. Thats prolly why they cost a bit more than the normal powerhead.

 

[ejmeier]

Okay, I need a lesson in pumps. Please somebody correct me if I'm wrong....

External pumps use an actual motor and shaft that spins a magnet inside the pump body, then this is sealed off from the water and a second magnet - the impeller magnet - is on the wet side, and is the only part that contacts water. This is why external pumps can't be submerged, because there is an actual moving part inside the pump, and you can't just dump a bunch of epoxy in there to seal it off. Is this correct?

(Note: I emailed Iwaki and they said that it is the motor that dictates the direction of the spin, and on the larger pumps that you wire the power cord yourself, it would be possible to mis-wire them and have them spin backwards.)

Now with submersible powerheads, I start to get lost. Is it just two electro-magnets inside there, alternating between the two that makes the impeller magnet spin? That way you could seal it off and make it submersible, but you have no way of controlling which way the magnet will spin. This is where it gets a little fuzzy... How would a Tunze be able to work?

 

[orlenz]

ok I am going to get a couple octura 2035 props for a maaxi 900, do I get lefthand or righthand props?

 

[Brent Thomann]

<a href=showthread.php?s=&postid=6975516#post6975516 target=_blank>Originally posted</a> by orlenz
ok I am going to get a couple octura 2035 props for a maaxi 900, do I get lefthand or righthand props?

doesn't matter.

 

[dhnguyen]

The controllable Tunzes use DC motors and only spin one way.
The lower end non-controllable ones use AC motors and actually have brakes built in to prevent the reverse spinning.

 

[hyperfocal]

Note, if your local RC shop is out of "normal" propellers, don't buy one with a threaded brass insert thinking you'll be able to remove it and fill the void with epoxy.

That was experience talking ;-)

 

[Aquaduck]

<a href=showthread.php?s=&postid=6975993#post6975993 target=_blank>Originally posted</a> by dhnguyen
The controllable Tunzes use DC motors and only spin one way.
The lower end non-controllable ones use AC motors and actually have brakes built in to prevent the reverse spinning.

So the Tunze starts the wrong way and slams on the brakes. Then what? It reverses direction? How? Somebody with a Tunze care to post pictures of this braking mechanism. Maybe we can get an idea from it for the Maxi-Mod.

 

[hyperfocal]

My foolish reply deleted :strooper: I'll read better next time.

 

[rsteagall]

for what its worth and to let everyone know how we feel about this mod, the Middle Tennessee Reef Club (MTRC) is meeting tomorrow and will be prefabing about 30-40 of these modifications for reef members in an assembly line.

MTRC president made a few of them and showed how they all worked. Everyone loved it so much, we decided the next meeting would be dedicated pretty much to this modification.

 

[dhnguyen]

 

[Snarkys]

funrcboats emailed me to tell me they are out of the props and will get them sometime next week......

 

[dhnguyen]

<a href=showthread.php?s=&postid=6976827#post6976827 target=_blank>Originally posted</a> by Aquaduck
So the Tunze starts the wrong way and slams on the brakes. Then what? It reverses direction? How? Somebody with a Tunze care to post pictures of this braking mechanism. Maybe we can get an idea from it for the Maxi-Mod.

This is how the lower end Tunze works.


http://www.reeftank.com/html/turbellestream.html


According to Tunze:

"From a physics stand point it is very difficult to make a mag drive prop pump. The propeller of course pulls forward pulling the magnet out of place and stopping the pump. The solution is to use a centrifugal side brace brake mechanism as our pumps do. The brake shoes can be broken by a wavemaker because they do not get time to retract and for the pump to run properly, they are always in a state of working to correct the start up pressures. "



Sounds familiar? It functions kinda like our own "stopper" isn't it?

Some photos of the Tunze

Notice the white section on the magnet just below the propeller? That's the brake pad. As the magnet spins the wrong way, it is pulled out by the force of the propeller then the brake pad catches on to stop it and the magnet gets sucked back in again. Just like how the Maxi-mod stopper works.


D.

 

[Crooke]

For those of you with a few spare Aquaclear powerheads laying around (like myself), I just completed my first mod of an AC 50.

Parts different from the regular mod:

1.5" sch40 coupling
1.5" sch40 pipe

Everything else is exactly the same. The impeller is dead easy to remove and the flexible airline goes right over the top bit of the magnet housing.

To make the shroud, I used my dremel to remove the original bottom piece of the impeller housing (the part just below the nozzle that twists onto the motor housing). I glued this piece inside the 1.5" pvc coupling.

The coupling is a mm or two too large to attach to the motor housing by itself, but the original fitting slots inside the coupling nicely. The only problem is that there's not much material left for glueing once you cut it off, so I ended up having to push it all the way into the coupling and using the dremel to cut away a small channel for the grips.

Once done, the whole assembly slots onto the motor housing perfectly.

I used a single nitro hammer prop for this mod, which it turns easily. The flow is comparable to my seio 1500.

Excuse the rough cuts. You guys all make cutting grooves in piece of pipe look easy

 

[dhnguyen]

Very cool Crooke. Now we can call it the maxi-clear streaming mod :lol: No pimples added

 

[ejmeier]

<a href=showthread.php?s=&postid=6979614#post6979614 target=_blank>Originally posted</a> by dhnguyen
Notice the white section on the magnet just below the propeller? That's the brake pad. As the magnet spins the wrong way, it is pulled out by the force of the propeller then the brake pad catches on to stop it and the magnet gets sucked back in again. Just like how the Maxi-mod stopper works.

Heh, not quite like the Maxi-mod stopper.... Wasn't I rambling about putting the stopper down on the magnet end, rather than up on the prop side?

Yes, I was, way back on page 17 of the starter thread:

Maybe we could put something on the actual impeller magnet itself to stop/reverse the direction of the spin? Just a tiny little nub, and then another one extending out over the top of the impeller hole that is intergrated into the housing. Just a thought - might reduce stress on the prop and shaft, esp if running constantly on a wavemaker. You never know if doing this over the long term might disrupt that balance of the prop...

But I still have no idea how the Seios do it??? It should be obvious if there is a stopper of some sort, shouldn't it? Why wouldn't Tunze do it another way? Something must be missing here...

 

[dhnguyen]

Well I think it was zapata41 who noticed that the SEIO impeller blades are slanting the opposite direction than what we expect them to and he also stated that 99 times out of 100, his SEIO would spin the wrong way. Someone hahnmeister I think also mentioned the likelihood that the SEIO motor might be of the 4 pole type which ensures a uni-directional spin. Possibly...

I meant the Tunze's braking mechanism works in the same way as the maxi-mod stopper in that the magnet gets pulled out, stops, and is forced back in again.

You can't really copy this Tunze's braking system easily without actually modifying the motor port hole and the magnet itself. Too much risk in damaging the entire pump and other than the cosmetic factor, I don't see an advantage in doing so as the stopper I'm using now works and is simple to make.

 

[hahnmeister]

Just want to make sure everyone remembers that the TUNZE's with the brakes are the AC ones that are not like the newer speed/wave controlled ones. The new ones (6000, 6100, 6200) are DC motors and so they dont need a brake system.

"funrcboats emailed me to tell me they are out of the props and will get them sometime next week......"

-Snarkys

Bwuah ha ha!! (evil laugh). Thats because I bought them all!!!! lol. Got them today... Let the modding begin.

Hey, in case I need it, where can I get those PVC test caps online? The local HD doesnt seem to have them.

 

[hahnmeister]

oh, dhnguyen. some earlier models of the MJ streams did have a brake built into the prop. The airline shaft wasnt attached to the magnet, but rather had a screw type or spiral cut to the base so that if the magnet spun the wrong way, the prop never catched on the magnet and just got pushed up to the stopper. Then when the magnet went the right way, it would catch and spin as the prop retracted into place.

 

[hahnmeister]

Ok, I cant find it right now...where is the link to buy the 1.5" PVC test caps online?