hot ecs cold motor?
 

hi guys,

i forgot what hot ecs/cold motor meant. does it mean i am undergeared?
my gearing is 22/58 in an erevo with 6s lipo and MMM combo. the MMM felt cold, and the weather is freezing, but the fan on it keeps coming on and off

thanks guys

With hard running on 6S, I'm sure the Combo is pulling some amperage. At the same time, how do you like the performance?

The MMM ESC has a thermistor on board that controls the fan. It turns the fan on to cool down and when she's cool again, it turns it off.

This ESC is somewhat shrouded, meaning it doesn't get much airflow naturally.

If the fan is only cycling, I wouldn't worry too much.

Hot ESC and cold motor usually means over geared. Cold ESC and hot motor usually means under geared.

Is the trans the smae as the emaxx one? If it is that gearing seems a little high. Put it into BrianG's spped calc and gear for 40.

You're probably walking the line as far as ESC temps go, but if you look back through some of the threads under Castle Creations, you will find more information about the ESC temps and operation of the cooling fan.

The fan comes on at 140 degrees, and doesn't shut off until it gets below 140 degrees.

This is well within the safe operating limits of the ESC.

If you want it to run cooler or want more runtime, then gear it down some.

My 2 cents.

Im geared for 40mph on 4s and my fan comes on alot too. I think its b/c the esc doesnt have an exposed heatsink so it trapps the heat until the fan comes on. I have never gotten a heat reading above 105*F off the esc. The motor get to about 135*

If your motor is cold stick with it b/c thats good!!! The monster will handle it!

cool thanks for the replies guys. what do you mean by high and low gearing?
im trying to gear for 60mph (according to the speed calculator).
the performance is quite good as in i get good run times and top speed, but it does not have that much power. it will wheelie but after a bit of effort on high traction surfaces, but it will never do a backflip for some reason

Tall gearing reduces torque- you need lots of torque to do backflips, and the Erevo doesnt backflip as easily as the emaxx as it is. Tall gearing (22/58 on 6s with ?kv motor again?) will also work the esc harder as the motor pulls more current when geared taller- hence the fan coming on for short periods. 60mph isnt an everyday setup for an MT, 40-45mph would be more sensible and the esc would stay cooler without the fan needed to come on. If you want to backflip, I would lower the gearing, lower punch control, and increase start power; if you have the extended wheelbase rear arms, loose those too.

Hot ESC = low C rated or inadequate batteries. This goes along with low torque as torque is a function of how fast a battery can discharge. The heat is from ripple current from inadequate batteries. Ripple current is a larger topic than I can go into here.

Bernie

BTW, the giveaway you link to in your thread only works for people who live in the UK... I read the terms and conditions, might want to add that info to your sig, as it is worthless to about 99% of this site's members.

And more info on your setup, such as batteries and motor would help...

i dont think i can fit any more characters in my sig, im not sure if it has a limit like on the traxxas forums (who made me take it off... said it was "advertising" :whip:) anyway i just post it everywhere.

with my setup i am using two 3s 5000mah neuenergy 30/60C lipos, so they should be good enough i imagine. every thing else about the e-revo is pretty much stock like wheels and stuff.
as for motor i am using the MMM 2200kv combo

You are running good batteries. That is not an issue so listen to the gearing guys.

Bernie

IMO 22/58 is a bit tall. Get a 62T spur gear and it should all be fine. I ran my 1.5D on 22/62 in my conversion and it ran very well, max temp I ever got was 145 and the 1.5D is a hotter motor than the motor you've got.