mod on maxijet powerhead
- Thread starter fishking
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chipmaker
Active Member
I just can not see any way that the pump can alternate direction of flow by alternating the plugs prongs. Its AC, so your current flow alternates continually......If its a DC or UNiversal motor yes it wuld work, but still would not work on a AC supply. It would have to be a DC power source for it to be able to alternate flow............Its simply not doable as it goes against the properties of electricity.
viper_930
Active Member
Originally Posted by chipmaker
I could buy that concept of just making the current flow in the tank a different direction, but its highly unlikely the pump itself changed its rotation, at least not without a lot of fancey secondary armature windings, switches etc......
How else could it have switched flow direction? It's a well-known mod used with a wavemaker to turn off/on the powerhead.
I could buy that concept of just making the current flow in the tank a different direction, but its highly unlikely the pump itself changed its rotation, at least not without a lot of fancey secondary armature windings, switches etc......
How else could it have switched flow direction? It's a well-known mod used with a wavemaker to turn off/on the powerhead.
tronicsdr
Member
I have done the modification on all my MaxiJets as well. I use a wavemaker for my timer. Pretty much every time they turn off and back on it will switch the flow on roughly a 45 degree axis. As far as the thereoy goes. The impeller is swithcing directions. The comment about the AC winding needing to be different would apply to a 3 phase motor and the rotation being different since this is a single phase pump it works a little differently. There isn't any secondary windings the magnets are attached directly on the impeller itself. I have an electonics back ground and I had a hard time with it at first as well but it really does work...
slipknot23
Member
Did you do this to the powerhead???
chipmaker
Active Member
Being that it is magnetic armature, perhaps, but I still do not see how. Look at any reversible rotation motor, it matters not what its on, and it consists of a heap more innards to reverse rotations than merely turning the plug around in a recepticle......DC is the only motors that will reverse rotation due to polarity. If yu know about electronics, then you understand that AC is alternaitng, so it matters not what line is hooked up per se for hot, and neutal. The plugs are polarized to keep nutrals with nutrals and hot with hot, through out the grid system, so hots are switched off and not neutrals or grounds......If the rotation was indeed reversed, it wold be counter to the volute of the pump....and no matter what rotation pump was going, if it oculd have pushed water out the outlet, its still going in the same direction and that is out.....so how could you tell rotation is reversed.....It certainly is not going to pull in water through the outlet port and puish it out the inlet port now is it? NOw, electronics background or not, that theory does not hld water in any shape or fashion as it just is not gonna happen or at least not enough to make it a reliable way of reverseing directions. It natters not if the pump is a magnetic armature, magnets are fixed with a given pole being N and the other S and when current flows though the field those magnets are going to go a given direction, and cause armature to rotate.......Simply not doable..........Care to explain how windings need to be different to apply to a 3 phase motor..3 phase motors are perhaps simplier and have more in common with these simple pumps. It takes reversing switches, centrifugal switches, a drum or rotary multiple position switch and a totally different set of windings to reverse rotation ona single phase motor. A three phase motor has three sets of windings each offset a bit off phase to start it rotating. The armature is not constructed of magnetic material so it can have its rotation change by reversing flow through the field coils, unlike a magnet with a "fixed" north and south pole on the armature......Have you ever heard of EMF, well think about it and see how it applied to the pump and other motors........
chipmaker
Active Member
Originally Posted by Tronicsdr
SNIP. There isn't any secondary windings the magnets are attached directly on the impeller itself. I have an electonics back ground and I had a hard time with it at first as well but it really does work...
Thats the point the magnet is the armature.....so there fore its permanent, and those poles on the armature can not be changed. Since straight AC current alternates (hence the name alternating current) the 2 legs of the power source are switched back and forth at a rate of 60 cycles per second.........so its impossible just to turn a plug around and have the motor reverse.......Go drag out your electronic books, its just not gonna happen
that easy.
And unless an armature consists of a comutator which these motors do not, all windings would be in the field windings, and to reverse rotation in a typical AC motor you have to have secondary windings in the fields, wound 180 degrees opposite to primary windings for it to even think about reversing. Just try and stick two like poles of a magnet together it does not work.....yet opposites attract, its the alternaitng flow of current that pulls the armature around due to orientation of the magnetic armature.
SNIP. There isn't any secondary windings the magnets are attached directly on the impeller itself. I have an electonics back ground and I had a hard time with it at first as well but it really does work...
Thats the point the magnet is the armature.....so there fore its permanent, and those poles on the armature can not be changed. Since straight AC current alternates (hence the name alternating current) the 2 legs of the power source are switched back and forth at a rate of 60 cycles per second.........so its impossible just to turn a plug around and have the motor reverse.......Go drag out your electronic books, its just not gonna happen
that easy.
And unless an armature consists of a comutator which these motors do not, all windings would be in the field windings, and to reverse rotation in a typical AC motor you have to have secondary windings in the fields, wound 180 degrees opposite to primary windings for it to even think about reversing. Just try and stick two like poles of a magnet together it does not work.....yet opposites attract, its the alternaitng flow of current that pulls the armature around due to orientation of the magnetic armature.
chipmaker
Active Member
Below is the most simple way any motor that is capable of being run in reverse rotation can be wired up. Since the pumps are encapsulated, its virtually impossible to separate the connections from the windings to reposition them with a drum or rotsry switch to allow reverse current flow. It simply can not be done utilizing the two conductors or even the three on grounded types to achieve a reverse rotation.....Since these motors fit the clasificatin of a shaded pole or induction motor, with a non wound armature it would be even harder to accomplish. Series or Universal type motors which have a wound armature and brushes (which no pumps have) would be the easiest, not counting a DC type motor where simply reversing the leads will do it......
slipknot23
Member
Look at the video for the maxijet powerhead mod http://www.melevsreef.com/video/mj_mod.wmv