problems with 3300's

[yokoracer]

hi guys i am encountering over heating motors with the new 3300's does any one have found a metod to keep it a bit cooler HELP my championship is about to begin. I am Running an MR4 Sp with a corally 21 single motor and i am geared for 5 min at SPgear 67 Pinion 30 / 31

[cutting_edge]

I think the Experts in the forums will need a little more info about your problem to be able to help you i.e Motor , gearing , Car . did it overheat befor with your old cells? which were? ect ect

everyone will try to help i am sure

[yokoracer]

I am Running an MR4 Sp with a corally 21 single motor and i am geared for 5 min at SPgear 67 Pinion 30 / 31

[johnbull]

Jean,

We are all experiencing your problems, as you know. I have been blowing armatures apart like they are going out of fashion. It is the combination of heat, top grade Corally cells, and track grip.

I finally managed a 5 minute run yesterday at a blistering pace and no loss of speed towards the end of the run.

As soon as I am convinced that my motor set up is OK, and it wasn't just a fluke I will pass the info over to everybody at the track like I always do.

If we can get the modifieds to run for 5 minutes, we will certainly manage with Stock.

Looks like it's going to be a great championship this year.

See you at the track.

Joe.

[yokoracer]

joe i know you will let me know i have no douth about that i was just trying to see if every one else encountered the same problem and what he did to solve it .
i am starting to convince my self that with a higher pinion its better this morning i when to the trach and had a few runs i geared 67X33 and it was fast and the motor heat was not that bad about the championship i agree with you this morning there were two new guys running yokomos they look very interested one of them use to race two years ago

[BC Rog]

The 33's (especially GP's) have a lower internal resisitance than 3k's so they can release the energy faster, some of this is un-necessary and turns to heat. Nothing much we can do about that as NiMH are here to stay and will keep getting lower in IR.

Rog

[yokoracer]

thanks for your help !!!! so all we can do is try to give some more air flow near the motor !!!!!

[BC Rog]

yep, also the bolt on motor plate heat sink (the one that fits to the underside of the mount) is well worth the £10 it costs!!!

Rog

[DA_cookie_monstA]

Well, as these cells are SO punchy, I would recomend you either

a) if you got an older speedo, turn the torque limiter on, not like a lot used to do was to turn it to full (no limiter)

b) if you got a newer speedo that only limits output for a preset period of time(1 second at full throttle or something like that), make sure it is set you you are never in a position where the torque limit cuts out before you have to back the throttle off.

Another thing to help is to increase the drive frequency for the speedo, you will lose a little punch, but will let the motor run cooler.

Something someone else recommended to me was to set neutral so when you pick the car up, the wheels turn slowly, but not actually enough to drive the car when on the ground.

[johnbull]

Hi friends. Greetings from Malta.

I have been following this one with interest as I too have been having overheating problems, as most of us have, not just here in HOT Malta but also in other countries.

Thanks Roger and Cookie for the suggestions.

With regard to cooling the motor, there are two possible approaches.
a) heatsinks which will spread the heat.
b) passing more air across the motor.

I have gone for the second alternative. I admit to having copied Masami, but I don't think that's such a disgrace!

I have installed a 5 volt fan blowing at the motor end bell, and a duct which channels more cool air onto the motor. I made the duct from an F1 bodyshell nosecone. I have also drilled through the two small recesses in the SD motor mount so that more air can go straight through the motor.

That and a couple of small mods on the 10 turn motor (brushes, springs, timing, etc) seems to have reduced the problem. In fact I did 2 x 5 minute runs yesterday within 20 minutes of each other, without any loss of speed in the last minute, and the brush and comm condition was very acceptable. Naturally I would not risk running 2 heats at a race meeting without a skim and new brushes, but at least I know it will take it.

Regards

Joe from sunny Malta.

[cobra81li200]

Yep, I did exactly the same as Johnbull, and it works very well. Moreover, most of the drivers in france are using fans to cool their motors. With the GP, we have enough runtime to use some power to cool the motor (and the fan uses something like 20 mA in 5 minutes, so it's even possible to use it with 3000s).

After a run, I'm still able to touch my motor more than 5 seconds, wich is a good sign...

[DA_cookie_monstA]

Is there a web article on how to fit these fans to the car please?

[cobra81li200]

yes, but in french...

[yokoracer]

shanks to you all for helping me out especially joe that on race meeting although he is going on on his car he always menages to help me
thanks joe !!!

[johnbull]

Hi friends. Greetings from Malta.

COOKIE. Here's how I did it.

If you use a 12 v fan, wire it straight up to the speedo RED and BLACK leads. his way you can leave the fan running after you have finished a race, simply by turning off the speedo switch. The fan comes on or off by connecting or disconnecting the cells.

If you use a 5 v fan, you can wire it straight up to the receiver BAT socket (the empty one), or wire it like the 12 v. The 5 v turns faster and is therefore more effective. We certainly need all the cooling we can get, where we race.

Regards

Joew from sunny Malta.

[yokoracer]

joe i have fitted the 5V fan anf i tell you it realy blows like hell will it make a difference if i connect it directly to the battery wires the ones coming from the battery to the speedo in between or could it effect the performance ???

[johnbull]

jean.

2 ways you can fit 5 volt fan.

1. straight to the empty BAT terminal on the receiver.

2. to the red and black speedo wires. If you connect to the speedo wires you can turn the switch off so your speedo and receiver are not activated, and still use the fan.

regards

Joe.

[yokoracer]

joe doen it and it work very well
thanks a lot for you time !!!!!!!1