Brushless motor "miss fire"

Skalabala

Skalabala

1 kW
Joined
Feb 5, 2014
Messages
416
Location
South Africa
Hi members :)

My sensored big block style motor has an erratic miss fire :|
It runs smooth and then miss fires like a car engine

Like, zzzzzzzz t t zzzzzzz t zzzzzzz t t t zzzzzzzzz t zzzzzzzz :p
 
Skalabala said:
Hi members :)

My sensored big block style motor has an erratic miss fire :|
It runs smooth and then miss fires like a car engine

Like, zzzzzzzz t t zzzzzzz t zzzzzzz t t t zzzzzzzzz t zzzzzzzz :p
Click to expand...

If it was working fine before, then it's most likely a bad connection somewhere. Run it with the wheel safely off the ground and wiggle the wires and connectors to recreate it.
 
Thank you for the reply :)
The motor is free running. It is a new motor and controller I got.
So it is doing this an bench testing.

Could it be bad quality hall sensor? It is from Alibaba :|
 
Can someone please help? :oops: :cry:
 
I have swapped the wires so the throttle gets 4.3V and halls get 5V

But it still is not running smooth.

What will the next thing be to check? Hall sensors inside the motor and their positions?
 
Must I make a video clip of it running? Will that help for diagnosing?
 
I just read your message. It is possible LiveForPhysics would know. It would not hurt to send him a message and ask him. I don't have any knowledge on it. The only other ES member besides DrkAngel and the other guys who post regularly on my New ezip motor post is an ES member named Thud. He is familiar with brushless motors. He last posted on my Hobby King motor post also in e bike general discussion. He has not posted in awhile though. Thanks and good luck. I really want to see what that motor will do.

LC. out.
 
4.3V is a little low depending on the sensor. Honeywell SS41 min voltage is 4.5V. Your hall wires are probably not connected in the right order - it's still possible for the motor to run in this case but it could draw lots of current and it may be causing the symptoms you see.

It's important to connect the 5V and Gnd hall wires correctly, this should be easy as they're usually red and black.

The second controller you have has a "Study" wire. This automatically senses the correct hall sensor order (you must still connect 5V and Gnd to the correct hall wires). You can do some searches on using the study function but I think you connect the two study connectors together and run the motor for a few seconds and once it's running well you can leave the study wire disconnected.

You can test the hall sensors by measuring voltage between gnd and each of the three hall signal wires while turning the motor slowly by hand. They should toggle between 0V and 5V.

The other possibility is that the motor has too many poles and too high RPM for the controller which may not be able to stay in sync. Does it work correctly at low speeds?
 
Thanks so much for the replies guys!! Means a lot to me! Want to get this running so bad!!

I will do tests tonight and report back :)
I did open the motor and it is only 8 magnet rotor :/
 
if you keep having issues,
try isolating the hall wires away from the motor power wires. these a lot of noise in running an electrical motor (even brushless)
 
Thanks Thud. I hope it works for him. I want him to get it running as I want to race him when I get my new motor. AN FX 75-5 motor. Thanks.

LC. out.
 

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Thud said:
if you keep having issues,
try isolating the hall wires away from the motor power wires. these a lot of noise in running an electrical motor (even brushless)
Click to expand...

Hey bud! Thank you so much for reply :)
That was actually next on my thoughts :D So that means my brain is almost as big as yours right?? :lol:
 
Going to have a look at it a bit today :)
The motor has 12 teeth and 8 magnets.
 
If the two wires what I think are the hall angle learn wires then the motor runs really bad.
When they are not connected the motor runs without miss fire on full throttle.

After running about 2 minutes no load the motor is rather warm to the touch :|

When I put my multimeter on hall + and then on signal 1 2 3 then its 5.00V it drops when I turn the motor with my hand.
The voltage reading on the halls sometime sit on 0.00V when not turning the motor :?
The one sensor sits at 0.17V most of the time when not turning :?
 
Ran the hall signal wires externally and no change :(
 
I actually get this on both my sensorless Bafang hubs powered by my Golden Motor controller. https://goo.gl/photos/LWJUMMRpphr2ZMXd9 I'm sure I read that this was a known problem somewhere (fixed by overclocking the controller) but I can't find it. The other possibility I've though of is that it could be a controller speed limit. Not sure if the speed limit usually works on sensorless motors though, it would need calibration.
 
Any ideas why the one hall sensor will be at 0.17V whet not turning motor?
 
Picture of hall sensors and marking on pcb
2015-10-13%2018.09.38g.jpg
 
Hall sensor A is the one that like to be at 0.17V But does give 5V and 0V sometimes
 
Hope you get it going
 
DAND214 said:
Out of ideas? Change the sensor.

Dan
Click to expand...

:lol: Yes out of ideas, what sensors should I get? As I would like to do all 3 so that they are a matched set :)
 
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