Model Boat Mayhem

Technical, Techniques, Hints, and Tips => BRUSHLESS Motors and Speed Controllers => Topic started by: Terry on June 28, 2021, 04:10:29 pm

Title: Stalled Brushless Motor query
Post by: Terry on June 28, 2021, 04:10:29 pm
Showing my ignorance here. Will a stalled brushless motor destroy the speed controller?
I know a brushed motor will.
Cheers, Terry.
Title: Re: Stalled Motor query
Post by: Martin [Admin] on June 28, 2021, 04:42:30 pm
 
Good question..... never tested that!
Title: Re: Stalled Motor query
Post by: derekwarner on June 29, 2021, 12:28:36 am
A thought, just from the stovetop Terry  :embarrassed: ........they produce brushless motor speed controllers with various [ranging] current ratings don't they?......so this may help to understand that Black Magic ...or.... Green Steam


I am sure one of our "esteamed" {-)  Members will respond

Derek
Title: Re: Stalled Motor query
Post by: chas on June 29, 2021, 08:42:29 am
Neither a brushed or brushless motor will automatically destroy an esc, only if the stall current is greater than the esc can cope with. In practice, it often is, that is why fitting a fuse is always a good idea. The mystery is why this basic recommendation is so often ignored, risking the destruction of the equipment. Also, if the model has a lipo battery, the current drawn could ruin that as well.
Charles

Title: Re: Stalled Motor query
Post by: Taranis on June 29, 2021, 09:26:22 am
I only use ESC's that have built in overload protection.
Hobbywing Quicrun are relatively cheap and waterproof.
Title: Re: Stalled Motor query
Post by: canabus on June 29, 2021, 12:09:00 pm
Hi Taranis
I totally agree with ewe, the Quicrun 60 Amp is the best to use.


Change a few links for your requirements and no program card required !!!


Canabus
Title: Re: Stalled Brushless Motor query
Post by: JimG on July 03, 2021, 08:44:44 pm
I have tested a brushless motor/esc combo using a Wattmeter to see what happens if the motor is stalled. A brushed motor basically becomes a low resistance short if the motor stalls so can take a large current which can blow an esc. Brushless motors are very different, the motor coil resistance stays the same when stalled however the feedback to the esc will stop. As the esc uses this feedback to set the pulses to the motor to adjust the speed if there is no feedback the esc will lose sync with the motor affecting the power output. When tested I found that the current to a stalled brushless motor drops to a much lower value compared to the running motor. So your risk of blowing the esc with a stalled brushless is basically zero.
Jim
Title: Re: Stalled Brushless Motor query
Post by: chas on July 03, 2021, 11:42:42 pm
Interesting stuff, I guess the most important figure will be the current drawn at say 95 % of stall, i.e. as the motor tries to overcome whatever is around the prop.if that current is huge, it could be a problem for the esc.
Title: Re: Stalled Brushless Motor query
Post by: Tug Fanatic on July 04, 2021, 09:05:46 am
Interesting stuff, I guess the most important figure will be the current drawn at say 95 % of stall, i.e. as the motor tries to overcome whatever is around the prop.if that current is huge, it could be a problem for the esc.

So basically the same as wildly overloading the motor with a prop that is far too large. In that case the motor can overheat very quickly. A possible race to destruction.

I always use a fuse! (or two). I also prefer two engine/props models.
Title: Re: Stalled Brushless Motor query
Post by: Terry on July 04, 2021, 05:56:11 pm
Jim G, Chas, food for thought, thanks.