Blew a Leopard 4074 1774kv and ESC Today

[Diesel6401]

Went for a run today. Got bored waiting for batts to charge and started messing with stuff on my Skunk cat. Before today the setup was the following:

Motor: Leopard 4074 1774kv
Esc: Seaking 120
Timing: 15
Prop: CF48
Batts: 2x 2s 5000mah 40c's
Temps: Before today motor NEVER reached 100F and esc was always low 100F range

The prop today was a x447/3 I changed the motor timing to 11.25 and after about 2 minutes boat just stopped and made some crazy sound like the motor just shelled out and one of the 5.5s on the motor de-soldered. I got home and checked the esc, had fluid coming from the caps and no pop when connecting batts. Esc still read with the program box though. I added some new caps and the pop came back but the esc still doesn't operate with a spare (testing) motor. The motor I tested with a different esc and it worked it just don't sound like it did before. I ordered a new motor today and will order a new esc. Seaking 180 this time for the extra room. Anyone with a clue on why she blew? I spun a CF48 before no problem, I know the motor liked it just fine and the x447 shouldn't have spiked the amps that much. That motor should swing that prop no problem, I was on/off the throttle a lot today. Couldn't get wot turns like I normally do. That could have mad a difference. I will be loading video soon. Ran 50.1mph before

Video

[6sHyper]

I bet the esc went and took the motor with it, sucks dude, i blew a motor today too!! esc seems ok though

[keithbradley]

I'm guessing it didnt like the timing. Timing can change the heat a motor and esc make quite a bit. Did you usually run it at 15?

[m4a1usr]

1)Got bored waiting for batts to charge and started messing with stuff on my Skunk cat.

2) I was on/off the throttle a lot today. Couldn't get wot turns like I normally do. That could have mad a difference.

I think you hit 2 significant contributors Dale. At least on first glance. Could be something else combined. But undercharged batts might be the first issue, you already know partial on/off throttle habits are very detrimental to eff.

Would like to see the video for sure. It does suck no matter the reasons!

John

[Fluid]

The x477/3 has much more load than the CF48 does. It has a lot more blade area and because it does not flex it loads the motor even more. I am not certain if the 1774 Kv motor is a "Y" wind or a "D" wind - but if it was the latter then 11 degrees of timing advance would have increased the heat without adding power. Add in all that on-and-off acceleration and there could have been plenty to overheat things.

A de-soldered motor plug indicates very high temperatures due to amp draw. Hard to say about the motor, it could have de-maged or the windings could have partially shorted out. A 120 amp controller is not a lot for that setup.



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[Diesel6401]

I think you hit 2 significant contributors Dale. At least on first glance. Could be something else combined. But undercharged batts might be the first issue, you already know partial on/off throttle habits are very detrimental to eff.

Would like to see the video for sure. It does suck no matter the reasons!

John

The batts where fresh off the charger. To add to the on/off I caught wind a few times and you can kinda hear the prop load/unload I am sure that didn't help at all also. That combined with the partial throttle bad bad news

The x477/3 has much more load than the CF48 does. It has a lot more blade area and because it does not flex it loads the motor even more. I am not certain if the 1774 Kv motor is a "Y" wind or a "D" wind - but if it was the latter then 11 degrees of timing advance would have increased the heat without adding power. Add in all that on-and-off acceleration and there could have been plenty to overheat things.

A de-soldered motor plug indicates very high temperatures due to amp draw. Hard to say about the motor, it could have de-maged or the windings could have partially shorted out. A 120 amp controller is not a lot for that setup.



.

I believe the 1774kv is a Y and at 15 timing I had great success which also leads me to believe it's a y wind. I read it a LONG time ago when I first got this motor but I went back to leopard site and the specs not there. They are changing some things on their site and less and less specs are there. Weird. I think it's Y though.

[Meniscus]

Are you using the BEC or do you run a separate power source? With a setup that close to the edge on amps, I would not run the BEC. Of course, I hardly ever use the BEC unless it is micro, under 16".

[Diesel6401]

Are you using the BEC or do you run a separate power source? With a setup that close to the edge on amps, I would not run the BEC. Of course, I hardly ever use the BEC unless it is micro, under 16".

Yes I was using the bec. I only use a rx pack on 5s + setups. The funny part is the bec is on the esc that still works. The esc never went up in smoke and made a mess in the boat. It just died and the caps leaked the fluid. I thought I just killed the caps since I didn't have the pop on power up and fluid coming from the caps. Installed some new caps, got the pop back bec still works and the programming still works, but when you hook it up to a motor it just beeps and twitches the motor. I tried different throttle calibrations and nothing. I am going to tear the motor apart today and see what i can find. I don't trust the motor now though even though it bench tested. It just doesn't sound right.

* I have a swordy 200 sitting spare. I will waterproof it tonight and just run it in this boat. Motor is ordered, should be here soon. Ordered from Steve.

[Meniscus]

When running closer to the limit of Amps for my ESCs, I try to remove all stress which includes running a separate RX pack. To keep weight down, I typically use Energizer AA lithiums which also provide ample current for servos. I sometimes use AAA lithiums, but only when space is very limited.

Just an idea, but I sometimes check another motor at low speeds by hooking the wiring up to a known working motor. Essentially its a generator running in reverse. I can then spin with a drill and listen to the suspect motor at low speed. It is often apparent if there is an issue. It also means I don't have to risk an ESC. Call me silly and unconventional, but that's me!

I once had a 100A ESC that seems to be fine, but wouldn't run anything properly. I never did find out what was wrong with it, but suspected it was an unbalanced load since it was comprised of two boards. Originally it blew a cap. I replaced and tested, but it acted the same as yours. Never any smoke or other indications and wasn't wet. I never looked into it anymore and set it on the shelf.

On the motor, you may want to check to see if the shaft is spinning true. If not, at higher RPM, it could really be doing a number on the bearings.

[martin]

I think a 3 bladed 1447 metal prop over a 2 blade carbon 47mm or 48mm is the probable cause. Thanks.

[Diesel6401]

When running closer to the limit of Amps for my ESCs, I try to remove all stress which includes running a separate RX pack. To keep weight down, I typically use Energizer AA lithiums which also provide ample current for servos. I sometimes use AAA lithiums, but only when space is very limited.

Just an idea, but I sometimes check another motor at low speeds by hooking the wiring up to a known working motor. Essentially its a generator running in reverse. I can then spin with a drill and listen to the suspect motor at low speed. It is often apparent if there is an issue. It also means I don't have to risk an ESC. Call me silly and unconventional, but that's me!

I once had a 100A ESC that seems to be fine, but wouldn't run anything properly. I never did find out what was wrong with it, but suspected it was an unbalanced load since it was comprised of two boards. Originally it blew a cap. I replaced and tested, but it acted the same as yours. Never any smoke or other indications and wasn't wet. I never looked into it anymore and set it on the shelf.

On the motor, you may want to check to see if the shaft is spinning true. If not, at higher RPM, it could really be doing a number on the bearings.

Tore the motor apart didn't see anything really wrong with it but it smalled burnt inside. The rotor is still balanced with no damage and the magnets seemed strong. Im clueless on it, but I know I don't want to use it.

[Meniscus]

Sounds like a short. Did you check the leads? It shouldn't smell burnt.

[pyroM!KE]

I burnt a esc up last month on my MG and I found the culprit to be a drop of water that shorted 2 of the motor wires together..A single drop of water!! The esc didnt smoke or pop..It just quit..My motor stunk but still works..The motor wire insulation got hot so thats what the burnt smell was...Seriously..Whenever you plug your motor wires to the esc wires seal the point of connection with some liquid electrical tape..It works great! I replaced the stock esc with a SK180 and the motor is just fine..