is there an electrician in the house

[BTCat]

Jul 7, 2009 10:39:45 GMT -6 Raygun said:

I was an electrician and a certified welder and I have seen more crimped connectors fail than soldered. Having said that there is a right and wrong way to solder first you need to make a mechanical connection by twisting the wires together if you don't on the larger wires than yes there can be some resistance and if it gets hot enough the solder can let go. A properly done soldered connection will not cause an esc to fail or to draw more current, a crimped connector can heat up and through time of heating and cooling can and will loosen up causing more resistance. As far as residential and commercial wiring, crimped connectors in many states do not meet code because of high failure rate they still prefer the wire to be under a screw or mechanically compressed between two plates.. Ray

You bring up some good points, Ray. I am always thinking of the world of automotive, commercial and industrial applications. Mostly DC and electronic. The electrician's side of it doesn't enter my mind very much. Good points.

Also, I left an assumption out there and I need to clarify it. When I speak of crimps, I dismiss the butt splice type crimps and the local hardware type stuff. I have professional crimping tools and terminals/connectors designed for specific applications and current. That makes a huge difference. These are the types of crimps currently acceptable in my industry. Not the cheapo stuff.

Bottom line for me is that solder, as long as it isn't a cold joint, is best for the heli applications overall. Now if we could just get the Dean's people to make the connectors out of more heat resistant plastic...

[akphill]

RC i was picken sorry I actually own several flukes even have the ones that measure amp's running through an electric wire and that is the one i want to use in the test that i would like to do see how many amps are actually running through a esc when running the engine whether it is a solder joint or a crimp joint and like bt say's we are not talking the standard automotive type crimp I am talking real industrial crimping being done will let everyone know what i come up with

just a side note when you have a 140 amp esc is that all the time or is that spike amps it's good for ?

[Raygun]

You are correct BT there is only one crimped connection allowed in most residential and commercial wiring it was a Buchanan (spelling) connector and they are nice but take a high dollar tool to crimp and mostly just used on grounds. But crimped or soldered I cannot see an ESC giving up because of that there would have to be a more dramatic reason to warrant that otherwise we would have cars, trains and planes bursting into flames every minute. And I agree with you about the local hardware crimps they might get you by but I would not depend on them for anything that will end up costing you alot of money. Good point... Ray

[rcdbutz]

Phil, for a 140 Amp ESC it would be able to handle 140 Amps of continuous current draw and should be able to handle a burst current that is even higher, maybe 160 amps.

[akent]

Raygun is correct. Solder connections (properly done) are more reliable than any crimped connection. Silver solder (ROHS) is good for higher temperatures. But as BT knows, with really nice equipment, good crimps can be made.

There is also a lot more than meets the eye with these ESC's. The motors that we are dealing with are 3 phase brushless. There are groups of three 'phases' on every motor. These are windings in the motor that will generally contain only a few thousandths to a few hundreds of an ohm of resistance.
When the ESC puts current across two of these phases, a LOT of current flows for only a few microseconds to a few milliseconds, then it stops while the magnetic field does it's thing and then switches to a different combination of leads to use a different phase to keep the motor turning.
If the ESC processor hickups and keeps a phase energized longer than the critical time of a drive transistor's capability, it can fail catastrophically.
If a drive transistor fails, this can be catastrophic as well, leading to more and more current to flow in other transistors, ultimately destroying everything.
If a motor is overloaded, causing more current to flow than the ESC transistors can handle, this can cause drive transistor failure, too.

As far as I know, there is no overcurrent protection in any of our hobby level ESC's, or even BEC's for that matter. In my opinion, this is really poor, and potentially could be life threatening!

I also realize that we are all after cheap prices for these electronics, and these protections would cost a little more.

I keep threatening to design a super reliable ESC that you could short all day long... A major overload would manifest itself as a noisy motor...

Best,
Kent

[BTCat]

Jul 12, 2009 14:11:50 GMT -6 akent said:

I keep threatening to design a super reliable ESC that you could short all day long... A major overload would manifest itself as a noisy motor...

Best,
Kent

I would love to see you do that. I've read several threads where you make mention of the various things that could be Incorporated or problems that could be eliminated. It would be nice to see it done by someone who knows WTF ;D

[Raygun]

I would love to see Kent design an ESC with a built in converter and one for coaxials with two ESC's and a converter all in one I know he could do it. Ray