80b shutting down ?
 

Ive had my quark 80b for about a month now and resently (as soon as i put it in my ruslter i got) it has been shutting down at random for some reason i dont know if its thermling or what but it shuts down for a little bit and doesn't respond to throttle imputs the steering works but thats it. i give it about 5 sec or so and it starts working agian but as soon as i give it some throttle and take off it does it agian. as far as i can tell its not getting that hot, 140ish maby, i can hold my finger on the metal heat sink for almost 2 full seconds the motor on the other hand is hot enuff to sizzle water latterly could that be the problem way the controller is shutting off maby? :032:

Your gearing sounds to low.

took it out agian and when it shuts off the yellow led comes on what does that mean :002:

whats your gearing?

it was 84 18 but i stripped the spur on the first blip of the throttle so i put my 64t 32p spur in it with a 14t pinion basically the same ratio but i just put them in for the durability. i dont know what the tranny ratio is so i dont know if i need to go up or down :002:

My 125 does this. I think it's losing the motor. I.E. Motor thermalling. Next time it does it, tap the brakes then go forward. Usually finds itself.

ya thats what i have to do but sometimes i have to let it sit for a bit before it goes again it gets bad though basicly it shuts off i wait 5 or 6 seconds then i can take off agian then it goes maby 40 feet and shuts off :035: .

It sounds like its a thermal issue, I have a 125 and when the case gets about 140 it thermals. I think it is set to thermal at 170f but that is internal temp not case temp. If you search the subject there are a few threads on it but I think they are about the 125 not the 80 but they should apply to both.

Get a heatsink and fan on that thing. The motor too. If you can sizle water, you r gonna fry the motor sooner rather than later.

Yeah. The motor must be at 100*C or 212*C to sizzle water.

My quark sits at about 95*F so it's definetly undergeared.

How does the controller know what the motor temp is?

It doesnt, it is a measurement of the internal case temp. of the controller it has no idea what the motors temp is. When the motor is 200f the the controller isnt far behind. The motor heats up the three leads going into the controller which transfers the heat into it. Add this to the heat the controller itself is producing and you have got one hot controller. If you would measure the heat of the case and compare it to the heat of the three solder connections (were the three motor leads are attached to the exposed board sticking out of the controller case) you would see a 20-30f difference.

As I understand it... The motor heats up if you spinn it to fast. When it heats up it loses effiency. When it loses efficency, it draws more amps. when it draws more amps the ESC heats up from the higher load. When the ESC heats up too much.... it thermals.

Well how it works is a BL motor has a "sweetspot" as for gearing. If you undergear it the motor will run hot from no load and from a lower amp draw, if you over gear it the motor will run cool but the ESC will run hot because of the added amp draw from the excessive load of being overgeared.

From an amp-draw perspective, what Squee said may not make much sense, but you have to remember that these BL motors are AC motors. As such, there are other factors like inductive reactance, power factor, etc that come into play that can make a large difference in current draw and temperature.

When motor current draw is high, but there is little motor heat, this means the motor is presenting a highly inductive load, which tends to be hard on the driving circuitry (ESC) and heats it up.

When the motor is hot, the motor is presenting more of a resistive load to the controller due to the frequency of the AC signal and loading of the motor. Resistive loads are the easiest to drive and therefore the ESC is cooler (still depends on the current draw though somewhat).

If the motor and ESC are about equal in temperature, then there is a good balance of resistance and inductive reactance, and power factor is closest to the ideal value of "1".

It's the resistive component of the motors windings that create the heat (and any other mechanical/electrical losses). On an ESC, the majority of the heat is generated by the rise time of the square wave pulses across the FETS devices. During this time, the voltage is neither on or off so there is a voltage drop AND current draw - hence the heat. When FETs are off, there is a voltage drop but no current draw so no heat. When the FETs are fully on, there is is current, but no voltage drop, so no heat there either.

This is oversimplification because there is a LOT of thought that goes into the design of an ESC and its feedback/speed sensing circuitry.

BTW: Ask any master electrician and they can tell you all about BL motors but they know them as "squirrel cage" motors and have been around for a LONG time. AC drive circuits are not new either, but their use in R/C is relatively new in comparison because we take DC and create PWM AC to drive the motor. ANY 3-phase AC motor is really a brushless motor.

ok guys back to me :005:. is my gearing off? whats ideal for a rusty? i plan on getting a fan for the controller, and a diff motor is in the near future so i can get rid of this 5mm shaft s can so i can run the gearing i wont.

....

maby some people dident see it what gearing is ideal for a rusty?

nobody knows how to gear a rusty :rolleyes:

Do you have a set of pinions? Sometimes experimenting with different numbers of teeth is as better way of finding the ideal gearing that having others tell you what it is.
If you go back to 48p gears, Robinson Racing makes some nice pinion gear sets. BTW, 32p IMO isn't necessary. What's most important is gear mesh and the flexing of the motor plate (if you have the stock plastic tranny).

What motor are you running? Being able to strip the gear is pretty good power, Maybe you got too much motor for the esc

Gear stripping doesn't only come from power. If the motor plate flexes so that the gear mesh changes, then just about any brushless power will strip the spur gear. Since switching to an aluminum tranny case, the only spur gear stripping I do is either my error with gear mesh or else I didn't tighten the motor screws enough.

Yup. Metalman is right. Stampy...gear down! That will solve your problems, or should...Try 2 teeth to begin with.

well the issue is my motor has a 5mm shaft and 18teeth is the smallest they make in 48p. so im basically stuck until i can get a diff motor. metal, its a stock tranny case so im sure its flexing. with the slipper tighted all the way down it strips 48p gears in the first hit of full power:eek: and the gear mess is set correctly, im not a noob to rc i can set gear mesh with my eyes closed :027:

squee's suggestion to drop two teeth should do it. Mike doesn't have any 32p 5mm bore 12t pinions, though.

nope the thing with that is the pinoin would be so thin that the set srew would more than likly strip :(. I just need a diff motor. id like to get a 380c 8L but i dont know if they make one. i was told the 9t would work but would run alittle hot on 3s how bout a lenher 1920 what turn would work good on a 3s? there alittle pricy but if they run like the 1950s then it should be well worth it :)

Yea, a 1920 would be the best way to go.

what turn should i go with? there 1/8" shafts right?

I think there 4mm but I'm not sure to be honest.

i think your right they are 4mm lame:002: what about a lenher xl 3600 would one work in a rusty? a new motor is a must now! :035: dont know what happend but i know its bad

Um, that motor doesn't look too healthy to me...

The XL3100 would be great in a rusty. I ran a XL4200 for a while and it was really good. But I went to 3s Lipo and needed to get a lower KV motor.

You could even just run the Basic 3100 (not XL) and it would be really good.

would a xl3600 on 3s work well with my quark 80b?

nvm its 97 amps:031: any body know how powerfull a Kontronik Twist 42 is? jamie from starluck said he would sell me one for like 140 should i do it:002:

4200kv seems like it would be too much for 11.1. You will be reving it really high and it will probbly run hot. I got rid of my XL4200 cuz it ran to hot on 3s. I would recomend going for something more in the 3000-3500kv range. You can gear ir up and get just as much speed, it just runss cooler. Especially if you go w/ the basic XL. It will have plenty of torque to gear it up.

I really think the Basic 3100 would be ideal for a rusty on 3s.

The XL3600 should work well I would think. Somebody correct me if I'm wrong though.

97 amps is to much for the 80b though :(

You can't go by that rating...The XL3600 in a ST on 3S shouldn't pull that many amps.

cool sweet guees ill order it up today :018: