NEW MMM v3 issues... - RC-Monster Forums

shaunjohnson · **NEW MMM v3 issues... -** 01.18.2009, 04:09 AM

it's only one and it's visual.

my friend just got his V3 today and i must say it looks very nice, cant run it yet untill he gets a motor though

BUT,
both the phase plugs and the battery input plugs are VERY disturbingly close to the heatsink.
i know this is a little issue and has caused some accidents before.
like it's scary close, maby 1mm in some places.

to try and prevent 200+amps going through the heatsink on contact we have placed some tight fitting heatshrink over each bullet socet to try and prevent any arking should the bullets move a tiny amount.

but i mean it, very scary, IMO i think that castle should continue making the V3's but just give a little more head room to the heatsink and bullets.
shaun

XSKAPE · 01.18.2009, 05:50 AM

Since when does plastic conduct electricity?

FG101C · 01.18.2009, 06:14 AM

I would think if you put heatshrink on the bullets that plug into the bullets on the esc you would not have an issue. That heatshrink would keep them from touching, it does on the two v3's and one v2 I have.

shaunjohnson · 06:51 AM

no plastic dosnet conduct electricity

it was just a little too close to cumfort, for instance...if i was to have a large ipact of some dirty conducting substance unluckily shorted the battery over the heatsink...
yes the anodising/paint coating would have to be probably worn off the heatsink first.

ok look dont matter, just expressing my concerns.

oh wait hang on...
i'm talking about the FEMALE 6mm bullet on the power BOARD of the MMM, that part is close to the heatsink, not the male that plugs into it.

E-fanatic · 01.18.2009, 08:21 AM

my first v3 mmm had the bullets touching the heatsink. Didnt cause and issues though. It was a resister falling off the board that killed it. Hope to have it back in a few weeks!! Then another project will begain!

George16 · 01.18.2009, 08:37 AM

According to Castle, there is no issue with the bullet touching the heatsink

. Patrick posted this before.

brushlessboy16 · 01.18.2009, 10:00 AM

Quote:

Originally Posted by George16

According to Castle, there is no issue with the bullet touching the heatsink

. Patrick posted this before.

Thats the truth.

He has said it time and time again, The components of the esc have a lower resistance then that heatsink... therefore it will go through the board and not the heatsink.... Its fine.

shaunjohnson · 01.18.2009, 03:47 PM

Quote:

Originally Posted by brushlessboy16

Thats the truth.

He has said it time and time again, The components of the esc have a lower resistance then that heatsink... therefore it will go through the board and not the heatsink.... Its fine.

aww that is soo cool

thanks guys!!

BrianG · 01.18.2009, 08:13 PM

Quote:

Originally Posted by brushlessboy16

...The components of the esc have a lower resistance then that heatsink... therefore it will go through the board and not the heatsink.... Its fine.

That's not quite what he said. The motor has a lower resistance than the heatsink. The ESC (hopefully) has infinite resistance from the + and - power inputs.

Despite all that, I still don't like the idea of the heatsink even partially shorting the battery TBH.

George16 · 01.18.2009, 08:35 PM

Quote:

Originally Posted by BrianG

That's not quite what he said. The motor has a lower resistance than the heatsink. The ESC (hopefully) has infinite resistance from the + and - power inputs.

Despite all that, I still don't like the idea of the heatsink even partially shorting the battery TBH.

Same here that's why I still installed heatshrink on the bullets.

Unsullied_Spy · 01.18.2009, 09:18 PM

Quote:

Originally Posted by shaunjohnson

aww that is soo cool

thanks guys!!

They also said that if you were to get conductivity it would ablate the aluminum on the heatsink and may not burn up the ESC. If you're really concerned you could heatshrink the plugs or bend the fins on the heatsink out of the way. I personally can't recommend altering the ESC in any way as it could potentially void the warranty.

pasan · 01.20.2009, 03:44 AM

I received the V3 case today, so while the board was naked I covered up the battery terminals with a bit of heat shrink, just to be on the safe side. There's really no danger at all from the motor phase wires touching the heat sink.

01.20.2009, 03:15 PM

My v3 shorted against the heat sink. At least I think that is what happened. Car was on the track and a burst of lightening lit up my body. Here is a picture of the results. Notice a chunk of the bullet is missing. Didn't kill the ESC, but the spark was massive.

Afterwards, I bent the heat sink back a tad and put a little shrink tube on the female bullet. Good as new.

RBMike · 03:34 PM

Ya, there it is. I know Patrick say's it's fine but I bent the fins away & put shrink tube on the connectors. Specially on the battery side. Also I open them all up & put shrink tube on the fan wires that WILL get cut by the edge of the board eventually. I'll risk the warrenty to make sure the fans wires don't short & kill the BEC. I'm not bashing the MMM, I have 4 & they are the best you can get for even twice the price but I still think they need a mechanical redesign.

pasan · 01.20.2009, 03:29 PM

Woah. Are you sure it touched the heatsink though? Is there a scorching on the fin? Looks like a 100amps went through that bit..