Cheap Wavemaker

[Anonymous]

Hello fellow reef addicts

I just get off the phone with radio shack and found out that they have a timer with 48 On/Off settings for $9.99.

I think this timer would serve the purpose, don't you all agree? I mean....... half an hour on and half an hour off is much better than on all the time. Especially when you have to pay at least $100 for a real wavemaker.

 

[Anonymous]

yup. I used to use this setup for wave simulation, and I think you can get 2 for $10 at places like Home Depot.

 

[Anonymous]

Be careful - these kinds of timers have a "hard start" as opposed to a "soft start", like some of the more expensive timers. The "hard start" will trash your powerheads in a short amount of time, although the maxi-jet pumps seem to last longer than most. HTH,
KA

 

[Anonymous]

Its not a bad idea but I prefer to have my pwr heads on/off every 5-10 mins. But for that price its a nice option.

 

[Anonymous]

I have used one for over a year now and have had no power head problems. (Rio 1700) I recently bought a power surge and set it on the same timer. It seems to be doing fine. I think the timer cost about $5. at Home Depot????

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http://www.xmission.com/~mikeb/heil.html

 

[Anonymous]

Folks!

I thought i found a cheap timer, it seems like you guys made out better than me. I went to Home Depot yesterday looking for those timer myself, the best i found was 24 On/Off. Which department did you find it?

 

[Anonymous]

I'm still under the impression that there is no such thing as a "hard" or "soft" start. These pumps are either on or off, and anything that suggests starting one way is easier on the pump is simply a gimmic.

Can you explain what the expensive timers do that makes the way they work a "soft" start KA?

 

[Anonymous]

I agreed!


As an electrical engineer, I can't figure out what the heck is soft and hard start. Unless the timer slowly turns on the powerheads the same way we turn on the lighting in our house with the dimmer switch. OR they are talking about the surge protection for the powerheads, then it's entirely different. Sometime manufacturers change the terminology to fool customers. It's part of the marketing strategy. Instead of saying surge protection, they say soft start.

The only way to proof this is to test both units with an oscilloscope meter. I am sure the different aren't that much, but the dollar amount is.

 

[Anonymous]

Bluebox is right, there is no such thing as a soft start, it's a gimmick.
Powerheads theese days are engineered pretty tough, they can usually take the abuse, besides in this hobby powerheads are fairly cheap.

 

[Anonymous]

I could be wrong but what i thought they were talking about was what part of the AC waveform it started the power to the pump. It starts the power to the pump at the beginning of the rise on the + side to prevent pump "jitter"

I wouldn't agree or disagree with the theory, it's just what i read as an explanation.

 

[Anonymous]

One thing that you cannot do with a cheap on/off timer is get alternating pumps. With most commercial wavemakers you can, and I use that ability to get the tank swirling in different directions every 5 minutes or so.

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Randy Holmes-Farley

 

[Anonymous]

well, being that my company sells pumps all kinds big and small. 3gmp to 8000gmp. i also work on and install them. there is no such this as a soft start on a single phase motor, soft starts are used only on 3 phase. the only time you need to have soft start is when you have a high horse power motor drawing alot of amps say around 6000 if it were hooked up "across the line" if you have that situation that many amps will blow something up so there is another method of wiring and its called wye-delta closed transition starting. where the motor starts on one set of leads at a low RPM to cut back on the inrush of amps. then it switches over to the other set of leads and runs at full RMP. hope this explains things a little. if it were true that single phase motors that stop and start frequently would burn up eventually, is wrong. how about well pumps? they stop and start all the time. the inrush of amps on powerhead motors is so small that no damage would occure. ok enough said by me. sorry it was so long

[This message has been edited by gnx87 (edited 21 January 2000).]

[This message has been edited by gnx87 (edited 21 January 2000).]

 

[Anonymous]

gnx87:

While I'm not claiming that wavemakers do actually provide a soft start, I think you are missing one of the main points. It's not the motors themselves that have a problem, its the impellers. The startup is (by conventional wisdom) very hard on them, since they get up to speed very rapidly. This rapid increase in speed puts stress on the blades, and results in them breaking off. I use a wavmaker (Tsunami, though it doesn't claim a soft start) and I get plenty of broken impellers, but never a ruined motor.

Further, I believe (though I'm not a motor expert) that it is quite possible to reduce the startup rate of such motors by changing the frequency of the electrical signal. If it is ramped from, say 1 Hz to 60 Hz, that would give them a soft start. Do wavemakers currently availabel do that? I have no idea as I've never measured one. I expect not.

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Randy Holmes-Farley

 

[Anonymous]

I agree with Randy. Some powerheads such as Hagen have the impeller in a loose arangement on the shaft with a little slack in it. When it starts the impeller clicks against the stop until it finally cracks, the motor is still fine. On the other hand, maxijets have a rigid impeller shaft and are not subject to this problem. When I first got my wavemaker, I tore up two Hagens in less that two weeks. I now have been running 12 Maxijets for 4 months with no problems.

 

[Anonymous]

As someone who has researched and built soft start circuits for powerhead motors I think the people that say there is no such thing as "soft start" for these motors don't know what they are talking about.
Most people are confused as to what soft start for these cheap little motors is so being an expert on this particular subject I will try to clear up the confusion.

Why do these motors need soft start?
because the constant on and off that wavemakers produce would in short order destroy the impellers of the pump.

If you inspect one of these impellers you will see that the blades are flat, straight up and down, not angled like a true pump impeller should be. This is because the coil of the motor is just a two pole coil. When the alternating current flows through the coil it produces a flip flopping magnetic field. The armature of the motor is a permanent magnet that is supposed to rotate 360 degrees and keep on going around and around. Well this armature has a definite weight and doesn't follow the flip flopping magnetic field very well in the begining and by the time it starts to move one way the magnetic field has changed and is asking it to move the other. That is why all these powerheads click and chatter on start up. The armature and the impeller are not rigedly coupled together.This is because the water resistance would add too much resistance to the armature movement and the motor would never start and just vibrate back and forth forever. So they loosly couple these two parts so the inertia of the armature can carry it around.
So soft start cannot stop these powerheads from chattering , in fact the more you reduce the voltage to them the more they chatter. All soft start circuits do is (by two methods) reduce the forces with which these two parts smack together so they last longer.
This is done two ways electronically
1. the starting current to the coil is reduced for a very short time and allowed to rise to its normal value.
2. The motor is only allowed to start when the ac current waveform is at the zero crossing point (transitioning from negative to positive and vice versa).
So before you say there is no such thing as soft start you should find out if you really know what your talking about.

[This message has been edited by old salt (edited 22 January 2000).]

 

[Anonymous]

OK what about a SCR fired unit with DC injection? That would solve all the above!

 

[Anonymous]

randy holmes farley is right. The ONLY way to keep the clattering out of your power heads is to use a variable frequency inverter. To send slowly increasing frequency of alternating current to the power heads. This would be very expensive and will never happen. The only solution I think is to use shaded pole motors or universal motors or dc motors. Or better yet get rid of all those ugly power heads and get a sea swirl or surge device.

 

[Anonymous]

With the Hagen powerheads you can use a little bit of silicone to keep the impeller at the loaded position, then you don't have the problem of teh shaft catching up with the impeller and cracking/breaking it.
Works for me
HTH
Derek

 

[Anonymous]

I use a red sea wavemaker which boasts soft start on my 180 and i love it, except that it should come with one extra outlet, so if you have the main pump plugged in you can still have 4 power heads working , otherwise its 3 ph's and the main pump.

before the wavemaker, i had everything on a regular powerstrip and after feeding time when it switched everything back on it was clak,clack,clack, and everything was on, now its just whoosh, and its on

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My 180 Utopia: Updated 5/21/00

 

[Anonymous]

Just thought I'd throw in a "3 cheers for Osci-Wave!"

Mount a Maxi-Jet to the rotating shaft of the Osci-Wave and BOOM! You've got an awesome wave shifting, ocean swirling tank! Costs only $99

I think by far though is the SeaSwirl since there are no impellors for anemonies to get sucked into!

-Nathan