Help! Mag Drive 7 Pump Won't Start!

ltkenbo

ltkenbo

Reefing newb
I am running a sump I just setup the other day with a magdrive 7 pump as the return pump. Anyways, in my room where the tank is I have a GFCI receptacle installed which I found out is a horrible idea with these pumps, cause they always trip all the time. So earlier I had my mom feed my fish for me and shee went up to the room and said the power was off (GFCI had tripped) so she reset it and when it came back on the mag pump didn't.

She didn't realize this but when I got home today it wasn't running and it will not turn on. I do not believe it could have burned out cause there is no siphon break in the overflow and I have tuned it as well as I topped the water off last night to normal level. Any ideas?

https://www.livingreefs.com/my-10-gallon-sump-55-gallon-aquarium-t21492p3.html
 
if the pump was powered up, but not runing for hours, its definately possible that the pump is dead... also, gfci's will have a tendance to trip if suddenly loaded with an inductive type load(motor) cause of the inrush currents and the spurious voltages that can sometimes get sent out on the ground wire, thus tripping the gfci. IF the pump is external, and IF you are sure that there is no electrical connection between the windings and the flow path(and there shouldnt be cause its a mag drive pump, and thats the whole point) then you can run the pump not on the gfci and perhaps reduce the issues, but there is a certain level of risk with that move, its something that you have to evaluate for yourself, but just think about this, if the pump were submerged, then i would definately say use the gfci, but if its external, then you can kinda get away without it, but if the pump were to get splashed, or something were to leak, your back into dangerous territory.
 
Yeah I figured out why it was tripping (electrical engineering student) the inductive load is storing up current and once it's shut off especially it cause an unbalance of current which the GFCI senses and then trips like its supposed to (current faulting to ground). Yeah the pump is submerged but since it keeps doing this I might have to take the GFCI out.

But I'm trying to figure out why it would just die.

I think I'm gonna call dr. foster and smith who I ordered it from and see if they'll send me a new one, I mean I don't understand why it would just die.
 
well, i disagree as to why the pump is causing the gfci to trip, if you really wanna get into it we can, but just so we're both on the same page, its not storing anything...

nothing wrong with calling them, but i'm thinking that they are gonna tell you that they dont warenty failures due to "external" equipment... starting and stopping a mag drive pump over and over and over like that can cause latent damage and could, over time, cause the coils to fail inside the main body of the pump....

if you have a kill-a-watt, or your sufficiently trained on how, you can measure the current draw of the pump and see if its pulling any current or not.. if not, then the coils are probably open, and its junk, or if you have an ohm meter, you can measure the impedance of the line cord, and that could tell you if its open or not. what would be even better is if you had another one you could compare readings against.
 
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I think that the pump is faulty. I have a mag 7 hooked up to a GFI and no problems of tripping. Especially if it is plugged in and not running.
 
Well it doesn't really matter but inductors store energy in the form of a magnetic field so if it was an inductive load technically it would be storing energy, power companies actually use giant motors as inductors sometimes. But dr. foster and smith told me they were going to send me a new one, they are overnighting it tomorrow so it will be here on Friday.
 
ltkenbo said:
Well it doesn't really matter but inductors store energy in the form of a magnetic field so if it was an inductive load technically it would be storing energy, power companies actually use giant motors as inductors sometimes. But dr. foster and smith told me they were going to send me a new one, they are overnighting it tomorrow so it will be here on Friday.
Click to expand...

ok, so lets get into it then....

your right, inductors do store energy in the form of a magnetic field, but in the case of something powered at 60Hz, its NOT STORING energy. The word storage, by defination, means to keep something for use at a later time.

The coils in the motor are acting like an inductor in that they are generating a magnetic field when energized, but, its not storing it, at 60Hz the slew rate of the sinewave is so slow, that the magnetic field can colapse FASTER than the slew rate. What this means is that there is no "storage" of power for use later.... All your actually ending up with is what is called BACK EMF(aka the flywheel effect). It has been prooven that inductive loads can sometimes cause "false positives" with gfci's because of this.

what you are experiencing is either an overly sensitive GFCI, or the pump has something physically(and electrically) wrong with it... i vote fot the latter,

I'm glad that they are sending you a new one... my luck they woulda told me to take a flying leap...

oh, and on the using motors as inductors thing... yea, they're called rotary phase converters.
 
Yeah I think the bad pump must have been tripping it cause I got the new one now and so far so good, no GFCI problems, so as long as it remains that way I won't take out the GFCI I installed in the room.
 
excelent, i'm glad you got it all back and running!

that old one probably got a few turns shorted internally, not enough to trip a breaker, but enough to cause other "leakage" issues...and thats whats tripping the gfci, or for all we know, water could have leaked inside the sealed motor compartment and is causing enough of a conduction path to cause your problems...

sorry, i didnt mean to preach, i've just been doing electrico-mechanical design and implementation for years and years, and this is exactly the kind of thing that people bring me to figure out... i'm kinda like the "the buck stops here for troubleshooting" guy, when i worked for motorola, and the other people couldnt figure out what was wrong with a circuit board, they would bring it to me, didnt matter if it was a lo-jack unit, an onstar module, a honda engine controller, or a eaton-fuller 18 wheeler transmition shift controller, when they brought it to me, i had to fix it....
 
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probably cause motorola makes some chitty phones...

you'll notice that i very specifically DIDNT list any cell phones, cause i dont work on them, thats done in florida... altho i did work for nextel for a while.. so if you ever wanna know how 16QAM works, just ask...
 
Oh I know Motorola makes crap phones. The only phones I have had any problems with were motorola phones. Poor battery life, reception bad menu system. All on motorola. My all time favorite brand of phone is Nokia. I dropped one from the second floor onto a concrete pad, went down put the parts back together and the thing worked for another 2 years before the battery started not holding a charge

Brian
 
Oh it's cool lol I actually quite enjoy debates, yeah I'm in electrical engineering now and I really like the saltwater hobby cause there's lot of things you can design and build.
 

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