Smoking ESC - RC-Monster Forums

MetalMan · 10.03.2008, 01:55 AM

I have a feeling the FETs blew due to the lack of input capacitance, not due to a short. Without capacitors the FETs can be exposed to some huge voltage spikes, especially during braking. This is why the MM can be made to run better in 1/8 with the addition of more low-ESR caps.

George16 · 10.03.2008, 06:11 AM

Quote:

Originally Posted by MetalMan

I have a feeling the FETs blew due to the lack of input capacitance, not due to a short. Without capacitors the FETs can be exposed to some huge voltage spikes, especially during braking. This is why the MM can be made to run better in 1/8 with the addition of more low-ESR caps.

I think you are right. It does make sense. The abrupt stop and go was probably too much for the FETs to handle without the caps.

lutach · 10.03.2008, 09:23 AM

Lito,

I sent you the usual e-mail with pictures of your box ready to be shipped out. I'll send you tracking number later today. Sorry about what happened and with the next unit, please take all the necessary precautions to prevent the caps from breaking. If you can, please do an extra capacitor bank and add it to the original place or to the power wires as close as you can to the ESC itself. Please look at the following pictures for your study(It's of my 100A and 200A ESC and you can see the little wire next to the power wires are from the capacitor and it's soldered together with the power wires):

lutach · 10.03.2008, 11:21 AM

Lito,

I posted a few pictures in the ESC thread. They are for references only and you can use different caps as well if needed. Please do like I did to secure the stock caps so they don't bounce around.

George16 · 10.03.2008, 08:12 PM

Quote:

Originally Posted by lutach

Lito,

I posted a few pictures in the ESC thread. They are for references only and you can use different caps as well if needed. Please do like I did to secure the stock caps so they don't bounce around.

Thanks for the pics. I'll definitely put more reinforcement in there to keep the caps from moving.

MetalMan · 10.03.2008, 01:28 PM

Quote:

Originally Posted by George16

I think you are right. It does make sense. The abrupt stop and go was probably too much for the FETs to handle without the caps.

Even Schultze tells you to use extra capacitors if your wires exceed a certain length. If my memory serves me correctly, this is due to the added inductance as a result of longer wires.

lutach · 10.03.2008, 01:48 PM

Quote:

Originally Posted by MetalMan

Even Schultze tells you to use extra capacitors if your wires exceed a certain length. If my memory serves me correctly, this is due to the added inductance as a result of longer wires.

True. The wires on my ESCs are short and thicker then most of the Schulze ESCs and only their big dogs use 2 wires. The problem was what you pointed out before.