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alvinlwh

What is going on here?

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Testing out a new radio set with an ESC motor setup I got around when I discovered this. 

ESC is a Skyrc Toro TS-50 sensored. 

Motor is a bluebottle 13.5T sensored. 

I forgot to plug the sensor cable in (as seen in the video it is hanging out of the motor) and still it ran. Plugged it it and it ran the same. Neither are "dual" modes like some HW/HK ESCs are. So how can it run without the sensor cable even of they are both supposed to be sensored? 

My only other BL ESCs are the TBLE-04S and that one will flash and beep and refuse to run without the sensor plugged in. 

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TS-50 can run in sensorless mode if no sensor is connected.  That's all that is happening here.  TBLE-04S doesn't have the ability to run sensorless motors.

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32 minutes ago, LongRat said:

TS-50 can run in sensorless mode if no sensor is connected.  That's all that is happening here.  TBLE-04S doesn't have the ability to run sensorless motors.

OK that is interesting info about the TS-50 and I looked again on Skyrc. Strange they list it as a sensored ESC and only mentioned sensorless in the specs box right at the bottom. 

How about the sensored motor? It can run without the sensor cable plugged in? Can all sensored brushless do this? 

Previously I mixed up the ABC wires and the motor will not run, will disconnecting the sensor make a sensored behave like a sensorless? 

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47 minutes ago, alvinlwh said:

Can all sensored brushless do this? 

 

Yes. I once entered a 2wd buggy race a year or two ago, and the first heat I ran without having connected the sensor lead. I realised whilst cleaning it, and round two I ran it connected. The top speed was the same, but it was SO MUCH smoother.

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26 minutes ago, toyolien said:

The top speed was the same, but it was SO MUCH smoother

Ah thanks, you beat me to my next question which will be "what are the advantages of sensored over sensorless". 

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Yep, the idea of the sensor cable is that it tells the esc exactly where the rotor is at any one time which prevents 'cogging' found in sensorless systems. Sensorless are fine for bashing where you don't need low speed throttle control. But I would always recommend sensored for anyone who likes their cars to be smooth and sensitive. And they are imperative for crawlers.

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@toyolien thanks. A different question if I may. I have another motor with a +11 sensor board, mounted at the +10 position, giving a total of +21 to timing. If I run it with the sensor cable disconnect (on a sensorless-able ESC of course), will it perform as a zero timing motor? 

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5 hours ago, alvinlwh said:

@toyolien thanks. A different question if I may. I have another motor with a +11 sensor board, mounted at the +10 position, giving a total of +21 to timing. If I run it with the sensor cable disconnect (on a sensorless-able ESC of course), will it perform as a zero timing motor? 

Not sure about that one. I'd only ever run sensored motors with a sensor cable...

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Yes it will perform as a zero timed motor.  All sensor-equipped motors can be driven by sensorless control.

Advantages of either type of control are often misrepresented I feel.  Different sensorless commutation algorithms on different ESCs mean there is not one answer.  The worst scenario with sensorless is a system which will barely start and is almost undrivable.  The best sensorless control I have driven was as smooth as a decent sensored system.  A couple of things to bear in mind: when sensorless, you are using the high power phase wires to transmit the rotor position signals, so it is really important these wires are as short as possible, and have equal, low resistance on all 3.  For me this means never using any connectors, always direct soldering, and cutting my wires to the exact, minimum length between motor and ESC.  That way, the really weak back EMF signals from a slowly turning motor are still seen cleanly at the ESC, which massively improves the low speed control and starting smoothness.

The advantages of sensorless shouldn't be overlooked - more simplicity, more reliability with fewer wires, waterproof and a smaller motor for the same output power.  This is why you won't see sensor based systems in any RC boats or planes any more.

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Thanks @LongRat. Useful information. The reason I was asking is I have an idea that I can run it as a +21 or +0 as desired by simply disconnecting the sensor. However I will need to swap out for a sensorless-able ESC first as it is on a TBLE at the moment.

I wasn't too convinced that the +21 seem to make any difference but this can be a quick and easy way to test instead of taking the motor apart to swap and shift the sensor board. 

As you can tell, I am new to this brushless game, I mostly got sensored as I was working with TBLE at first, now got Skyrc and HK ESCs. However I do have a Orion Vortex dDrive which is a sensorless I believe. 

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+21 degrees of timing will be very noticeable over the same motor running at 0 degrees.  You need to be sure though, that the electrical timing of the ESC is the same when running in sensorless and sensored mode, for the comparison to be meaningful.

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3 hours ago, LongRat said:

+21 degrees of timing will be very noticeable over the same motor running at 0 degrees.  You need to be sure though, that the electrical timing of the ESC is the same when running in sensorless and sensored mode, for the comparison to be meaningful.

There is a possibility that I am expecting too much from that motor to begin with. For the test, I intend to run it with and without the sensor cable, quick and simple to do. No messing with the ESC whatsoever. 

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