Identifying and restoring lynch/agni motor

[matt912836]

Taken off of a cycles maximus pedicab being powered by a 12v 275a curtis controller.

Can't find much info other than its a lynch motor. It has no labels or anything.

Trying to narrow down which one it is. I'm thinking its most likely an LEM170 or LEM200, what are some things I can do to identify specifics?

The diameter is ~8 inches and this thing has some serious heft to it.

I'm thinking first apply 12v dc voltage to it and somehow measure what rpm i get at the output. That way I'm able to calculate rpm/voltage, but any other ideas?

Also, its clearly in bad shape, it was taken from an abandoned pedicab which was literally left outside for years. You can see blue corrosion on the inside clear as day from the outside. Still spins freely with absolutely zero resistance. Is this even repairable or worth repairing if it is?? From my research this is one of the most efficient dc motor designs and this motor should be able to do 10kw+ reliably... I will try to get much more pics later.

For a controller im thinking of a CL350, since it can do both brushless and brushed motors.

 

[amberwolf]

Blue might be copper corrosion from winding insulation failure. If there's corrosion on the windings, you *might* be able to clean that up and then soak them in something like CoronaDope, and let that cure, to re-isolate and insulate them.

Otherwise, if you're not up for a motor rewind, the possible winding shorts corrosion indicates or causes is likely to cause you grief even if it still operates....because the corrosion may not be as conductive as a direct short, it might not seem like an issue until it's running at higher current or voltage.


What's the project you'd be using it for? (may help us help you find a suitable motor if this one isn't usable).

 

[matt912836]

Blue might be copper corrosion from winding insulation failure. If there's corrosion on the windings, you *might* be able to clean that up and then soak them in something like CoronaDope, and let that cure, to re-isolate and insulate them.

Otherwise, if you're not up for a motor rewind, the possible winding shorts corrosion indicates or causes is likely to cause you grief even if it still operates....because the corrosion may not be as conductive as a direct short, it might not seem like an issue until it's running at higher current or voltage.


What's the project you'd be using it for? (may help us help you find a suitable motor if this one isn't usable).

I'm almost 100% sure the corrosion is surface level from weathering and not from being overpowered or overheating... i don't think its even possible to "rewind" this motor? I don't think its made from regular strung copper.

After some cleaning, I found a stamp! 119-050313

So its an agni 119! and I'm assuming that's the date it was made.

The fact they had this motor running at 12v for 200a is insane to me, completely overkill for its intended purpose and could be a big score if its still in working condition. This was the same kind of motor in the original zeros if im not mistaken?

Applying dc voltage directly gets it to spin just fine, after about 36v this thing spins VIOLENTLY while attached to a vice!

This will be going into a KTM 300 exc frame previously i had a cyclone 6k in it which was wayyy underpowered, no good for more than getting the frame rolling to test the chassis out... i took the cyclone out and put it in the pedicab which was more than enough for that application, so taking this thing and throwing it in this frame instead with some decent power should wake the bike up a lot.

 

[amberwolf]

Well, if the blue is corrosion of the rotor copper itself, and not some other source (like the commutator bars), it means that whatever insulation was on the windings is damaged, and depending on where that is it could short to other conductors not carrying the same current/voltage at that instant.

If it's off the commutator, then it probably wont' affect much since they will just need to be re-bedded-in by operating the motor for however long that takes; the brushes will do this for you automatically.


There are a number of ways to make windings for a brushed motor; the most common is with typical "magnet wire", just thinly insulated copper. Some use Litz wire, which is a braid of very fine such wire. Either of these could be rewound, with the original wire type or the other type.

They could use cast or machined or shaped copper "bars"; I haven't ever run into one of those yet. This type can't be rewound with wire, most likely, but would need new "bars" like the old ones. These would be less likely to have shorts between them simply because they aren't wound with different conducting paths right on top of each other with only the thin insulation between them, if they're designed the way I've seen technical drawings of the type done.

But hey, if it's running, no harm in testing it out.

If you do take it apart to clean the insides out, don't clean or polish the commutator or brushes. (dusting them off is ok, but you don't want to undo the bedding in they already have if you don't have to).

 

[fechter]

I don't think those things really have insulation on the "windings". They're more like copper strips that are soldered at the ends. Surface corrosion on those wouldn't really be a problem. The part where the brushes run (commutator) is important.

 

[matt912836]

Well, if the blue is corrosion of the rotor copper itself, and not some other source (like the commutator bars), it means that whatever insulation was on the windings is damaged, and depending on where that is it could short to other conductors not carrying the same current/voltage at that instant.

If it's off the commutator, then it probably wont' affect much since they will just need to be re-bedded-in by operating the motor for however long that takes; the brushes will do this for you automatically.


There are a number of ways to make windings for a brushed motor; the most common is with typical "magnet wire", just thinly insulated copper. Some use Litz wire, which is a braid of very fine such wire. Either of these could be rewound, with the original wire type or the other type.

They could use cast or machined or shaped copper "bars"; I haven't ever run into one of those yet. This type can't be rewound with wire, most likely, but would need new "bars" like the old ones. These would be less likely to have shorts between them simply because they aren't wound with different conducting paths right on top of each other with only the thin insulation between them, if they're designed the way I've seen technical drawings of the type done.

But hey, if it's running, no harm in testing it out.

If you do take it apart to clean the insides out, don't clean or polish the commutator or brushes. (dusting them off is ok, but you don't want to undo the bedding in they already have if you don't have to).

That's actually exactly how this motor is! Copper strips/bars. Heres the inside of one (not mine):



So I took apart the brush holder and it was absolutely filthy in there, filled with dirt and grime that almost looked like grease, most of the brushes weren't even fully extended enough to make contact because of how gunked up! A nice thorough flush and clean with some simple green and now it has all the springs free and moving smoothly.

I unfortunately chiped one of the brushes while trying to free it from being stuck, it wasnt too much, after filing it down to be straight again its probably about lost about 2mm shorter than it originally was, it is still able to make good contact with the commutator.

I don't think those things really have insulation on the "windings". They're more like copper strips that are soldered at the ends. Surface corrosion on those wouldn't really be a problem. The part where the brushes run (commutator) is important.

Thats good to know! Thats exactly what they are, soldered copper strips. The brush assembly needed a nice deep cleaning to get the brushes freed up to make full contact,, but the commutator itself looks okay, though a pumice stone probably wouldn't hurt:




Unfortunately no before and after pics of the clean but its made a clear night and day difference even just having the motor on a vice and applying voltage.

Before, the motor wouldn't really move much faster until you reached 36v. This was giving it voltage directly from a battery, increasing voltage by going up cell by cell. Now, you can see the clear difference between rpms each cell you go up! Theres also a slight squeaking which i first thought was a bearing that was bad that is now completely gone, must have just been all that grit that was in there.

Now I feel its ready for some real power!

 

[fechter]

That doesn't look too bad there.

If there were any shorts between the windings, the no-load current would be abnormally high and there would be some resistance to spinning it by hand.

Those motors can make a lot of power in bursts, but you can overheat them with too much continuous. I've seen some that got hot enough for the connecting links to come unsoldered and fly apart.

 

[amberwolf]

I unfortunately chiped one of the brushes while trying to free it from being stuck, it wasnt too much, after filing it down to be straight again its probably about lost about 2mm shorter than it originally was, it is still able to make good contact with the commutator

The motor wont' run as well as it should until it beds itself in again to the commutator, so you may want to just set it up on a secure test stand of some sort and run it at low speed for a while until this happens. How long it takes depends on the brush hardness; the slower they were designed to wear, the longer this will take.

The current won't be distributed evenly thru a poorly-bedded brush, so it is probably better not to run high current thru it till it beds in.

 

[matt912836]

Now here lies the biggest issue!: is it actually worth it to invest a nice chunk of money into this older piece of tech?

Its going to cost atleast $400 in controller to give this thing decent power.

This is also disregarding the eventual brush wear after giving it any decent amount of use.. to replace the brushes down the line would cost another $400+..

Meanwhile, I already have high power brushless controllers lying around, which would pair nicely with a ~$400 brushless qs138...

Which motor would I get more performance out of? Does the axial flux tech make "going backwards" actually worth it?

The goal of the bike is a 50-60mph top speed with enough torque to get the front end off the ground with ease under 30mph.