Dary's tank!

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Hey Dary,
Sorry to read about your Tang.
I almost pulled the trigger on 2. 750 Koralia Evolutions, until I kept reading about that in the reviews. That and noise.
Without having the cash for Eco's, I just went with the Cobalt Maxi- jet 1200's, Sure-grips and careful placement. Italian Maxis worked for me in the past and matched my wavemaker( cheapy strip type).
I have to say, although linear in flow, they make no noise on start-up and only a little hum in operation.
After reading your experience, I'm glad I didn't get the Koralias. I would hate to lose any of my stock like that.
Again, sorry about your loss.
 
I have a 1050, 2 750s, and a 550. The one 750 used to do it, but has stopped. Unsure as to why. I believe I read somewhere that it was a known issue that they were looking into and have possibly solved. Don't recall fully.
 
As per the internet; Assuming the shaft bushings are intact check to see if the rubber stop in the front cover is still intact. This is the part that the prop will hit if it spins backwards and cause it to bounce and then change direction. Most AC motors can accidentally run backwards, but there is suppose to be a safety stop on the prop, at least there is on mine. Sorry about the poor tang.
 
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Both my koralias do the same thing, they do it a lot too. I don't have a wave maker so it doesn't really matter to me. I actually use it to my advantage because it removes the gunk in the propellers.
 
Very interesting discussion here..., the one in question is an older 750 , along with two 1400's and a 1050.,,, Greg., I'll check into that rubber stop when I get a replacement ,..thanks to everyone for their input,..I guess I'm not the only one who fell victim to this ph ,.. Just too bad a innocent little tang had to pay the ultimate price for something that maybe could have been avoided by a little better design,..She was really a cool little cutie who knew how to handle the grumpy old triggerfish .
 
An ac motor shouldn't run backwards by accident. It should run backward only if u change the polarity
 
Whether it is a single or three phase ac motor makes no difference. Same goes for a dc motor
 
Jason M said:
An ac motor shouldn't run backwards by accident. It should run backward only if u change the polarity
Click to expand...

Jason,.. A bee isn't suppose to be able to fly either but,......? Lol .... All I know is that it DID happen and apparently, it's happened to others too.
 
It does happen with those power heads but what was said was that ac motors somtimes run in reverse. Which they don't. The powerheads running in reverse maybe because of extremely cheap crappy built motors and that is a rarity for any motor to run backwards by itsself. If ac motors in general did do that a lot of lives would be lost in the process. I don't know how the power heads are designed but I have seen at as well. They would be the only one ac motors I've ever heard of that do that. That is if it is the motor causing it. I don't know if there are anypther components in play for the powerheads that may cause that issue
 
U got me thinking now about it and my stand is that the motor Jang running backwards but another componet is causing the reversal. It is just simply impossible for a magnent to change its polarity without u changing the legs on the power supply. Oh and i thought its said that a bumble bee is not suppose to be able to fly. Not all bees I think
 
Check out how a AC induction motor works before making statements. Quite different from a DC motor where polarity controls the direction of rotation. The impossibility of the motor running backwards is pretty apparent in Darys case as well as many others documented by Korallia, it happens. That is why a physical rubber stop was used. There are many safety measures in modern induction motors to insure they start in the right direction, I guess these fans have simpler motors in them.

There are no "other" components. The motor connects directly to the prop.
 
Reversing the polarity of the start winding in relationship to the run winding reverses the direction of rotation of all single-phase and three+phase ac motors. There are only two types: induction and asyncronous. The difference is that induction motors run a bit slower than the frequency they are fed. A asyncronous will run at the same speed as the frequency. U do know what that means right?. Induction, asyncronous, dc doesn't matter they all use magnets to create force moving a shaft or what ever else u put in there. Unless that coil inside the motor where to magically re wire itself of the poles connected to the 1 and 2 stamped in the connection point. It isn't changing. I read online that there are pieces between the shaft and motor. I couldn't find a technical drawing showing the design though. To be honest I dont care. It's just when I see a statement such as ac motors run backwards accidently sometimes I can't help but argue.
 
From what I've found out about that stop u talk of is that it stops the impeller from reversing while the polarity of the coils adjusts itself for the first 60 cycles. It's 60 because here in America we run with a frequency of 60 Hz. That's means there are 60 cycles per second of electricity reversal in an ac circuit for those that don't know. And if that stop at the end of the impelled isn't there the impeller can't right itself and stays in the wrong direction
 
Name a few of those safety measure will u Greg because I can only think of one and it doesn't have anything to do with "making sure the motor starts on the right direction"
 
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