Seaking 120A ESC, what should my timing be?

[MassiveOverkill]

So I have a CF2812 3300KV 8 magnet pole, 12 coil brushless on 2200 mAh 3S 30C batteries. What should my ESC timing be?

Pics:

Left motor is a standard CF2812 brushless. Right is Joysway frankenbrushless that I can't find anywhere. They removed 6 magnets (14 on left, 8 on right) and beefed up the gauge of the windings:



Motors put back together:



Windings of the stock Joysway Frankenbrushless:

[MassiveOverkill]

OK guys, I got my Seaking 120A ESC installed and man this thing jumps out of the water!! I've only done short 1-2 minute runs and the motor is running really hot. The driveshaft is pretty friction-free, but as I said in the other thread, a little heavier than teh stock drivetrain. I went from a 30mm prop to 32mm. I guess I could go back but I don't think it's the prop.

I've tried 3.75, 7.50, and 11.25 ESC timing and she still runs hot. If it's a timing thing, it should run cooler the lower the timing I use right? Cooling tube spits out a nice stream of water.

What do you think, try 0 degree timing? BTW I'm glad I got the programming card.

Oh, it's weird hot the motor responds to timing. When I had it at the most advanced of 11.25 the drivetrain sounded like a bumble bee, whereas the lower the timing I used the smoother she ran. I think I just answered my own question but would like more input.

Thanks.

[photohoward1]

Outrunners always run Hot. When you say hot? What temp? Outrunners also like a high degree of timing.

[MassiveOverkill]

Well the 'hold your finger for 5 seconds' test failed. Keep in mind that once I got my bearing situation resolved the motor on the stock ESC ran very cool to the touch immediately after the run.

Also keep in mind that my outrunner has about half the magnets it would normally have.

[Rumdog]

It has half the magnets....
So, what?
The timing probably isn't the issue. It's a cheap, tiny motor that can only be cooled with a cooled mount. As stated, outrunners run hot. Way hotter than a jacketed inrunner. Thing is, they can handle the heat.

[MassiveOverkill]

It has half the magnets....
So, what?
The timing probably isn't the issue. It's a cheap, tiny motor that can only be cooled with a cooled mount. As stated, outrunners run hot. Way hotter than a jacketed inrunner. Thing is, they can handle the heat.

What you mean this?!



FYI the motor ran cool on the old ESC and drivetrain before the stock ESC blew. It now has a new ESC and Octura drivetrain. You didn't even read my last post did you?

[Rumdog]

Yeah. That mount is what I mean. They don't do much for cooling. I'm willing to bet that the excessive heat is caused by your new drive setup.

[MassiveOverkill]

I had to ditch the new compression collet as it was too heavy and unbalanced. I drilled out my old brass collette to accomodate the larger .130 flexshaft as well as put some hot glue at the bottom of the motor so it mates with the plastic and vibrations are much less now.

Old collette was only 7 grams, new one was 12.

I'll restart ESC timing trials tommorrow.

[LiPo Power]

Go back to 30mm prop and see...
Its possible the little extra on the prop is installing enough load to get the motor wormer...

[MassiveOverkill]

I'm not ruling that out, but I'm going to check that as a last resort. I think the vibrations the Octura motor coupler was creating was the main culprit. I'll know tonight after work.

[lectriglide]

Outrunners also like a high degree of timing.

+1. Generally outrunners like 15 - 30 degrees of timing. They don't run worth a flip at less than 15.

[MassiveOverkill]

+1. Generally outrunners like 15 - 30 degrees of timing. They don't run worth a flip at less than 15.

And this is why I brought up question on the number of magnets or poles, which was shrugged off like it didn't matter:

http://www.rcgroups.com/forums/showthread.php?t=1408488

A default CF2812, which has 14 pole magnets would normally like to see 15-25 degrrees of timing, but mine is only an 8 pole motor, which puts it in one timing class lower.

[siberianhusky]

I think you may need to do something about the rest of the vibration, something in there is out of balance and this WILL cause inefficiency in the driveline.
" and vibrations are much less now. "
Should be smooth and vibration free.
A 2mm increase in prop diameter is a MAJOR change in load as well. So this could very well be your problem. You'd be very surprised if you saw the difference a 2mm change in prop size makes to amp draw if you had a data logger.
Last time out I put a slight cup in the tips of a prop and the amp draw went up almost 15 amps average for the run. A 10 amp increase would be massive for that little motor.
I have the headroom in that setup so 15 more amps was nothing to worry about, the motor and esc are more suited to each other amps wise also.
Your motor is seriously the weak link in your setup, you could over amp that motor and the esc wouldn't even get warm until the windings of the motor short!
Since the esc is basically bomb proof for that motor you have to be careful not to go too crazy on the props so you don't over amp the motor.
In short I'd solve the vibration issue so it runs smooth, go back to the 30mm prop which you know ran well and try medium timing to start, if things are ok bump it up to high and see what happens in a short run. Once you have the timing set try the 32mm prop and see how hot that gets in a minute of running.
You changed a whole pile of things at once so the problem could be with any of them or a combination.
Make one change or adjustment only then run the boat and see if that made it better or worse. Same way full size race teams track down problems on race weekend.

[MassiveOverkill]

Well removing the vibration means getting another motor, which means modifying the motor mount to take a standard outrunner. The vibration is there with just the original collette and has been there since the boat was stock. Even without the collette, the motor has minor vibration at certain points in the RPM range. It's not bad and doesn't persist throughout the entire RPM range. I guess I could try balancing the can, trying to determine what I could use that wouldn't fling off at 30K RPM....I guess I could use epoxy.

The existing motor mount is rather weak, which is why I've shored it up with hot-glue because the bottom of the motor mount is just free-hanging, and now it's at least mated to the hull. That alone has made a difference in vibration. I'll do a few short runs to make sure the heat problem is gone before I accept the hot glue as a long-term solution.

[martin]

Are you getting this vibration running the motor out of the water with no load on the motor. Outrunners will vibrate a lot more than inrunners if run with no load on the prop. Are you getting noticable vibration when the boat is in the water with load on the prop.

[MassiveOverkill]

Are you getting this vibration running the motor out of the water with no load on the motor. Outrunners will vibrate a lot more than inrunners if run with no load on the prop. Are you getting noticable vibration when the boat is in the water with load on the prop.

That's correct Martin, this was unloaded. The vibration now is the same as when it was new and didn't feel like it was going to shake the boat apart. When I temporarily had the Octura compression collette installed, the vibrations were so bad that I was afraid it was going to eventually crack the plastic mounts.

[martin]

If its not vibrating in the water under load dont worry about it, not advisable to run any motors with no load on them apart from just checking that the motor is running & in the right direction ecspecially outrunners as you do get more vibration over inrunners ecspcially some cheap outrunners have a lot of end float on them which isnt a problem once under load in the water. My outrunners that were running at over 42000rpm unloaded were unbeleivable on vibration, once in the water no problem at all.

[MassiveOverkill]

Thanks Martin, I only ran it for literally 5 seconds each check.

[MassiveOverkill]

Well, the motor is just cookin' Just a matter of time before a winding shorts. It's impressive though. I did put the original 30mm prop back on.

I'm thinking of putting the spare CF2812 rated at 1600KV and sticking the 32mm prop on and run it like that, or even mate it to a 3 blade prop. I've tried just about all the timing settings and have her at 3.5 now to try and keep her cool.

I did try swapping the 14 magnet shell of the CF2812 to the Joysway coil, but it didn't like it.......must be the way they were wound.

This is a testament to the Boca ceramic bearings though. Still going strong.

[MassiveOverkill]

Did WOT run yesterday, about 5-6 laps. Motor was still hot, but not as hot.....still could not keep my finger on for 5 seconds.

I'm wondering if the motor is pulling more amps now that it's being fed by a 120A ESC vs the stock 20A and that's actually causing the overheating. The boat is faster...........using the same battery and prop, so if there were drag in the new drivetrain, I would think it would be slower.

Stock CF2812 1600KV can pull max of 18 amps. This Joysway variant is rated at 3300KV. I can confirm that it's actually faster as I stuck the 1600KV motor in for a test run and it was dog slow. You figure twice the KV.......this motor is capable of pulling 36 amps, which is more than it's size was designed for as far as dissipating heat?

Joysway normally fits their boats with 30 Amp ESC's. I wonder if putting in a 20 Amp is their way of not overheating the motor.

Is there a way that I can use resistors to limit the maximum amps my ESC can feed to the motor to 20-25 amps? Say a modification of a Spark Arrestor. Would this hurt the ESC? I noticed the newest version of the Turnigy 120A ESC has acceleration settings. I wish I had that option now to test with.

[siberianhusky]

No offense but you really need to learn a little bit of electrical theory.
Check the answers you got on RCG about the esc, it was explained to you correctly there by Boaterguy no less!

"

Quote: Originally Posted by MassiveOverkill You guys think the Seaking 120A ESC is feeding the motor too much current? Nope, the ESC does not push current, neither do the packs. The motor will draw the amount of current it needs to spin the load, the bigger prop, the more current it will draw. If that current is higher than the motor can take, it will heat up until blowing. The current is drawn from the batteries through the ESC. If there is more current passing through the ESC than it can handle, it will also heat up until meltdown. There is nothing pushing current, therefore you can have components rated for as high as you want, I ran a 140A ESC on an airboat drawing 20-25 amps once."

[martin]

If you are refering to the specs that HK have on the T120a esc re brake - non, soft or hard. This info is wrong on the Marine 120a esc, their is no brake setting. Should read.
running mode
lipo cells
low voltage
timing.

[MassiveOverkill]

If you are refering to the specs that HK have on the T120a esc re brake - non, soft or hard. This info is wrong on the Marine 120a esc, their is no brake setting. Should read.
running mode
lipo cells
low voltage
timing.

Here's the one I was talking about:

http://hobbyking.com/hobbyking/store...ming_Card.html

[martin]

Yep crossed wires, i was reffering to the T120a & not the Aquastar.

[MassiveOverkill]

Yep crossed wires, i was reffering to the T120a & not the Aquastar.

Check your PM Martin.

[MassiveOverkill]

PROBLEM SOLVED!!! Thanks to all whe helped. Thanks to Rabosi (not on this forum) for pointing out my 'thrust' bearing was in the wrong place. Motor mount is nice and cool as well as the engine. Thing really flies!!!. I'll take another video after TS Debbie gets her butt out of town.

[MassiveOverkill]

Well problem partially solved: Throughout all my troubleshooting I've been using the stock 1800 mah 20C battery that came with the boat. Last night after getting the thrust bearing put on the front bearing everything ran nice and cool. I take her out this evening and figured "my problem's fixed, let's use the Grayson (2200 30C) batteries." First run went well and checked for heat afterwards and the damned thing is running hot again...........not so hot that smoke\steam was coming off of it but barely passing the finger test. I do a 2nd run with my 2nd Grayson pack and same result. Finally on my third run, I use the stock 1800 pack and what do you know...........running cool.

Stock battery 1800x20=36amps max draw.
Grayson battery 2200x30=66 amps max draw.

Grayson pack is also 179 grams to the stock battery's 138 grams. The boat only weights 514 grams without battery. Boat actually seems to run faster on the stock battery speedwise.

Videos of the two runs on Grayson batteries:

http://www.youtube.com/watch?v=HTOxOLvTfdM

http://www.youtube.com/watch?v=n5wWOYyi4Yg