Damaged esc

[alan p]

Had  a unfortunate 15sec maiden with a DF. 

Resulting damage to airframe now repaired. Two esc fitted  as it was a twin, one is ok other now appears dead.

Question how much of a hard  arrival will an esc take before it is u/s?

Both were good quality products from a recognised retailer/manufactuer and soft mounted to avoid shock damage.

My arrivals tend not to be of the best!!!

Advise from the experten on esc's will be welcome.

[Simon Chaddock]

If the 'arrival' was under power then it tends to come down to if and for how long the EDF was "stalled" by the fan touching the case.

EDFs have heavy motors and the fan is a very close fit in the duct. To make matters worse EDFs use a relatively high kV motor to achieve the required revs with a particularly low internal resistance and this is coupled to a big, high amp rated battery.

Most ESC are pretty mechanically robust but are electrically sensitive. It doesn't take much over load and in a fraction of a second its gone.

 

If you want confirmation it is 'dead' remove the heat sink. Most likely one or more of the MOSFETS will visibly show it is 'blown'.

It cannot be repaired but it does make it easier to chuck it away if you can see it damaged.😉

.

Edited August 28, 2022 by Simon Chaddock

[Philip Lewis 3]

With a hot air station that would be quite an easy repair, the problem would be more in identifying and obtaining the right component but pretty cheap if you can.

[alan p]

Hi Simon

Assuming the waxy appearance means they are blown?

[Simon Chaddock]

alan p

Normally a MOSFET fails from local heat actually in the micro chip itself which then damages the plastic encapsulating material.

Your ESC does not appear to show such obvious damage.

About the only suspicious mark is this, but it could just be a moulding mark..

 

If it were me I would connect the ESC up to another smaller motor with no load on the bench just to see if it runs.

In principle without very sophisticated test equipment 'substitution' is the only way to prove if it is the wiring or the component itself that is at fault.

I keep a spare ESC, driven from a servo tester so no radio required, with a screw connector and a 2 s battery so I can do a simple "does it run" test on almost any motor.

Even an EDF motor at low power on a 2s is not going to trouble a 30A ESC.

If it does run smoothly then I know the problem is with the ESC, the wiring or even the radio.

Edited August 29, 2022 by Simon Chaddock

[PeterF]

17 hours ago, alan p said:

Hi Simon

Assuming the waxy appearance means they are blown

The waxy substance may well be a thermal paste to improve conduction of heat from the MOSFET to the heat sink.

[RottenRow]

Could the ESC have failed during the short flight and been the cause if the abrupt arrival?

 

Otherwise, if the ESCs are connected to the throttle channel via a Y-lead, did you disconnect the red wire in the lead to one of the ESCs? Some types, with BEC fitted, don’t like being connected in parallel.

 

Brian.

[alan p]

thankyou for the advice chaps looks like a matter of elimination.  Hi RR one red lead was isolated.

Friend who did maiden said haven't the faintest what happened there!!!

[RottenRow]

Hi Alan,

 

I assume you still have the ESCs connected via the Y-lead? If you are testing them individually you’ll have to reconnect that red lead (or use a separate receiver battery). Sorry if I’m stating the obvious!

 

What is the model? If it has wing-mounted fans (like a Meteor for example) failure of one of them in flight would have caused asymmetric thrust and the model may have dived towards the ‘dead’ fan.

 

As you say, a process of elimination.

 

Brian. 

[alan p]

Hi RR

Model own design AR 234, it actually dived to the right but its the Lh esc that's u/s.