testing a ESC

[ericrw]

Is it possible to test an ESC,before actually putting it in and flying a model?

[Andy Green]

I assume you mean a brushless ESC.

You will have to connect it to a motor, you cannot test my simply measuring output voltage or looking at the waveform.

The motor send back pulses to the ESC to notify it of it's position. You can test on the bench, but as with any testing don't fit a prop to the motor.

Andy

[Andy48]

If you build yourself a static test rig which will clamp in a vice, and is securely able to move forward a few cm, you can mount the motor, prop, your ESC, a battery and a watt meter on it together with a cheapo luggage balance at the back to measure static thrust. Use a simple servo tester to drive the ESC. Then you can test the full combination, program your ESC, check the performance of different props etc., and then have the whole power train ready to install in a model. If you colour code each of the motor/ESC leads once it is working, then it will rotate correctly when fitted in the model.

Do always stand behind the test rig for safety.

[Phil Green]

I think what you're getting at is the conditions of sale of some internet vendors, whereby a 'used' ESC cannot be returned under warranty.

Obviously you cant solder the connections, but you can take an old motor, say a blue wonder, and solder a dressmaking pin to each lead. These can be inserted into the ends of the ESC wires without damaging or soldering anything. Similarly (and you have to be careful to avoid shorts here) you can solder a couple of pins to a lipo connector and stick them in the ends of the pos & neg.

Dont load the motor much (if at all) as the pins wont carry many amps. Once its all connected you can see if the motor spins up and you can test the BEC output, yet when its all disconnected again by pulling out the pins, no-one would ever know it had been run.

Cheers

Phil

Edited By Phil Green on 12/06/2013 23:00:31

[ericrw]

I have a brushless ESC that I think is faulty but on the other hand it may not be ! So I will set up a test rig as suggested !! Thanks to your responses. Eric.

[Biggles' Elder Brother - Moderator]

Hi Eric, do you have to put a prop on it to prove the ESC is working? In the case of IC testing we have to because it would be difficult to start the engine without a prop. But in electric that's not the case. Personally I would never attach a prop in the workshop to a live set up unless I had no choice - why take the risk if you don't need to?

BEB

[Andy48]

Surely testing an electric setup with a prop on a decent test rig is no different to bench testing an ic engine. Obviously it is better to do this outside in case the prop flies off. You probably do need to test an ESC with the prop on to ensure the ESC works up to its full current rating.

Edited By Martin Phillips on 13/06/2013 14:00:25

[Olly P]

Depends on the purpose of the test!

I often connect up a new ESC and motor without a prop to set everything (brake, direction etc) and do this all before I even look a installation. Once I'm happy with direction of rotation, and settings, I then strap it to my test block and attach a prop, before conducting static power testing (amps/watts).

Just my methodology - not neccessarilly right or wrong.

[ericrw]

I would certainly secure the test rig if there is a need to check the static power (amps/watts).

[Swissflyer]

Testing ESC & motor combinations on the bench has many benefits.

You can:

• Measure your motors’ real performance characteristics & find a good prop. Usually max power is about 60% of what the Hong Kong Website claims!
  
• Dynamically balance your EDF fans to cut down vibration, increase flight times and avoid noise complaints at the flying field. The attached picture shows the huge improvement by rotating the fan to 315deg before TDC on a cheap EDF. It was all I had to do to cure a horrible vibration but would have been impossible without bench testing.
  
  
  
  
• Find weak ESC’s before they destroy your model. I recently tested a 40A that is OK at 15A for the first 20 seconds, then overheats & stops! i.e. it would get a model just off the ground and then cut.

That said, please take safety precautions:

• Always wear safety goggles; I have had my safety goggles lightly struck by something on a couple of occasions.
• Build yourself a solid test mount and secure it really well

With all that done you will fly your models with a lighter & hopefully happier heart.

Mark

[Biggles' Elder Brother - Moderator]

Posted by Martin Phillips on 13/06/2013 13:59:06:

Surely testing an electric setup with a prop on a decent test rig is no different to bench testing an ic engine. Obviously it is better to do this outside in case the prop flies off. You probably do need to test an ESC with the prop on to ensure the ESC works up to its full current rating.

Edited By Martin Phillips on 13/06/2013 14:00:25

I didn't say that it was! The point I made Martin was that with an IC engine you have no choice - with an electric you do - so my point is why take an additional risk that you don't need to take?

I agree that for a full power train test you can indeed do you decribe. But, that not what the OP has asked - he ask how he could test an ESC outside of a model, not how to test the prop/motor/ESC/battery combination. For a simple functionality test on an ESC he does not need the prop - and my view is that he would therefore be better off without it!

BEB

[JohnSom]

I seem to have accumulated a number of ESCs in my spares box - as you do. The problem is that not all are labelled as to amperage. The physical size does provide some guide to capacity but I wondered if there was anyway of determining more accurately, for example, with the use of a multimeter ?

John

[Phil Green]

>>I wondered if there was anyway of determining more accurately, for example, with the use of a multimeter ?

No, its all down to the type and number of paralleled FETs used. You can make an informed guess based on the guage of the wire used, the width of the PCB tracks and the size of the input decoupling capacitors, but it is just a guess. Theres nothing much you can do with a multimeter to check its current-carrying capacity.

Cheers

Phil

Edited By Phil Green on 08/07/2013 15:47:02

[JohnSom]

Thanks Phil for a helpful reply. With the help of your pointers and by adopting a cautious approach I should be able to make a calculated guess.

John