Need advise on MG Tracker 34 PRO trolling motor

[andreipou]

Hi,
This motor had seized LU.
Two out of 4 magnets got loose and when I tried to move them rest of 4 came of too.
I glued them back , but when I apply the power now shaft moves ,but does not rotate.
The armature test shows no continuity from copper clams to shaft, but zero resistance between all the copper clams of winding.
I assume all wires shortened...

My problem is that I am not able to locate this particular model on the web.
I did not find any serial number on motor.
Only what is on the pictures below.
Can you help me to identify this motor better, so I look for replacement armature?

Or , maybe any other advise....

 

[gm280]

First of all, if I am understand everything correctly, you basically had all four permanent magnets that are on the LU shell (the stator) break off from the shell. And you re-glued them back. And than you applied power and the armature moved, aligned with the magnets, but not spinning. So you read the resistance on the commutators of the armature and everything read zero ohms to every other commutator position. Okay, sound like you got one or more of the magnets glued backwards. Meaning they are not glued like they originally were installed from the factory. So you have to figure out which ones go which direction and change them. The reason the armature isn't spinning is because once it align magnetically with the wrong direction magnets, they won't move any further or spin. The zero reading with the ohm meter is because the resistance is so low your meter shows zero. I would say that the armature is okay. But the four magnets need changed directions to make it all spin again. But mind you, this is only from the information you provided and I am not there to verify that assumption myself. Hope that help a little to get it working again.

 

[andreipou]

You are right, I forgot to pay attention to polarities, but later I thought about it and try to test it with small magnet to see if they "suck"\"push" it differently. Test did not work. I even try to pry one magnet, but JB Weld holds strong. I was afraid to break it.
It was stupid , but this was my first time doing it...
I think it is what you say since we both thought about it and judging on the way shaft moves a little when power applied and stops like something holds it (while without power it spins by hand).

I just need to figure how to get magnets off without breaking.
Is there a way to determine which one is in wrong direction?

Maybe, if I find long magnet I try to push it against each one to see how they push\suck it.

 

[andreipou]

As a plan B, can I take this new lower unit and just replace the whole thing?
It has the same 4 wires (black, red, yellow, red).
Thread on the pipe should be the same, right?

TROLLING MOTOR - MotorGuide Tracker Series - Lower Unit Assembly(46# - 5 Speed) (M899702T) | PerfProTech.com

Find your Lower Unit Assembly(46# - 5 Speed) (M899702T) diagrams at PPT using our TROLLING MOTOR parts catalog.

www.perfprotech.com

What do you think?

 

[gm280]

Of course a new replacement LU housing will work. But only if it is the exact house for your TM. So if you decide to go that route, make sure it is the connect model for your LU.

 

[andreipou]

Of course a new replacement LU housing will work. But only if it is the exact house for your TM. So if you decide to go that route, make sure it is the connect model for your LU.

That is the problem that started this thread: I am not able to find serial number or model number and the name "MotorGuide Tracker 34 Pro" does not show on the Web.
I see "MG Tracker" models and "MG Pro" models, but no "MG Tracker Pro" models.
And no 34# models.
Maybe, it is too old...
Boat is from 1985 and last registration was in 2010.

But, this is my thinking about new LU:
I am not talking about replacing just a housing, but the the whole LU Assembly ( click on the link) . All "work" of this motor is done by LU, right? The only thing "top" part does, it provides 12V via 4 wires. If LU has same 4 wires and same pipe thread there will be nothing to prevent it from working, right?
Is my thinking correct? Need to get opinion to make sure I do not want to make more stupid mistakes....

 

[gm280]

Well since you are basically talking about replacing the entire LU completely, I can't see why it shouldn't work. But surely that has to cost a pretty penny too. I was trying to get you running again with the least costly way. But go for it and KEEP the old LU for possible parts... JMHO

 

[andreipou]

Well since you are basically talking about replacing the entire LU completely, I can't see why it shouldn't work. But surely that has to cost a pretty penny too. I was trying to get you running again with the least costly way. But go for it and KEEP the old LU for possible parts... JMHO

Yes, that was what I really wanted to do, but I was not able to determine direction of polarity without taking magnets off.
I tried to heat JBWeld using gas torch from outside of the housing and punch magnet out using piece of wood. I was able to get out one magnet so far with just a small corner piece of it broken.
Even when it is out it is hard to determine the direction of polarity because it is not along the magnet. It is somehow from outer round side to inner round side (do not know how to explain it better).
So, even if I get them all out it will be difficult to figure how to put them in correctly. (Big mental note always to mark magnets direction BEFORE taking them out of the housing)
Now, to make things worse the white plastic of the plate that holds carbon brushes completely deteriorated. I noticed it was cracking in two places and use small pieces of thin steel and JBW to fix it, but plastic is like sand cookie now just fell into 4 separate parts in new spots.
I can try to solder it out and glue pieces together then solder back, but not sure it will work well.
So, even if everything works after all the hard work it will be motor ready to fall apart.
The new plates look differently and run $50-$70.
Feels like effort exceeds benefits now.
On another hand, I found LU for $150 shipped . Seems like a lot of money for the part, but it will be practically new motor (all parts that do the work will be new) and new motor cost $500 and up.
And motor will be 46# instead of 34#...
I am saying all those thing loudly trying to convince myself on what is better to do...

 

[andreipou]

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[andreipou]

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I was able to remove all magnets (it was hard).
I tested polarity with compass and they are not the same.
There are two pairs of opposite polarities.
S an N is not on the ends , they are on large curved sides of the magnets ( see pics), so direction of the magnet should not matter . but position does as far as they go S-N-S-N, right?
I decided to complete this fix even if it does not work just for the sake of learning how to do this.
And I always have plan B...

 

[andreipou]

Eventually got contact plate glued together piece by piece.
Glued magnets in S-N-S-N order.
Motor runs!
But two issues:
1. Runs in opposite directions (reverse). Not sure if I have to re-glue magnets shifting them from S-N-S-N to N-S-N-S (90 degrees shift of magnets) or just switch black and red wires in the head (not sure how it will work with 2 other wires : blue and yellow and additional speed copper coils).
2. There is some intermittent resistance when I turn it by hand . It feels like it rubs on something inside (magnets?) and gets very hot very quickly and I have to turn it off to avoid wire insulation melting.

 

[gm280]

I have to say, you have persistence, that's for sure. You are correct with how to get it to turn the opposite direction. However, the fact that you are having serious heat, tells me you also have a huge current draw and that points to something drawing way more current than it is supposed to. There should never be wires getting hot enough to melt their insulation. So you still have something not correct. Could be the armature partially shorted with a winding, or something like that. Use your meter to check every commutator to try and isolate if that is happening. Also test the armature commentator to the metal shaft. There shouldn't be any connection reading to the armature shaft ever. Let us know...