Problems with QS Motor when in hall sensor 5 position

I have an issue on a QS motor whereby if the hall position is in position 5 (noted from the MQCON screen), the controller is unable to initiate the motor and throws an "over current" error. Using a hall diagnostic tool I have been able to ascertain that the hall positions correspond with the phase colourings below:
1 blue
2 blue/yellow
3 blue/green
4 green/yellow
5 green
6 yellow

If the throttle is applied from any other position, the motor starts smoothly.

There is also another symptom to this where if the motor is placed under load, it will make a "grinding" noise (which can be heard here - ) I am presuming this is when the stator moves into hall position 5.

I am unsure how I can troubleshoot this further and was hoping to get some advice.

Some background and troubleshooting I have completed on the bike which started these problems after a phase/hall wire replacement which wiped out a number of hall sensors in the process. These have been replaced by an electric motor repair specialist and all report back ok using the diagnostic tool. I have checked that the phase/hall wiring is inline using the tool which can be seen on this slow motion video -
The phase wires have continuity between them and I get between 00.5-00.7 resistance between each phase.

Initiating the hall test makes the controller jolt the wheel quite aggressively, sometimes this jolt is left to freewheel to a stop, sometimes it stops it and continues moving the wheel. It makes about 8 small turns and then stops. No error, no completed just sits there with no status. I have left this for about 4min with no change.

The secondary hall wire, when plugged in causes a "lack voltage" error which I am not sure where to begin with this one!

There is possibility that one or more of the hall sensors that was replaced is the wrong type. I think your motor needs bipolar sensors. Maybe some of the replacements are unipolar.

I once bought a set of bipolar hall sensors and a unipolar sensor got mixed up in the batch. And I didn’t notice until I tested them all after fitting.


It’s difficult to tell using your tester, but using a multimeter would confirm whether or not they are unipolar or bipolar.

Thanks for the reply, the make of Hall sensor was going to be the next thing to query with the person who replaced the halls. I found out from QA after they were replaced that they use Honeywell SS413F. I get the feeling the sensors they used are ones that would work in much smaller motors (such as scooters).

I have performed basic voltage tests between the halls, but unsure how I would test for unipolar or bipolar hall type. Would you be able to advise or point me in the right direction?

SS413F are bipolar, so when you turn the wheel very slowly these hall sensors turn on and stay on until they see a magnet with the opposite pole and then switch off.

A unipolar sensor will switch off when the magnetic field of the correct polarity disappears.

The simple way to see it is a bipolar hall sensor will stay on much longer than a unipolar hall sensor. You may see that using your hall testing meter if you turn the motor very slowly by hand.

I have just been to check and I don’t see any noticeable delays, in fact when going slowly and feeling the magnet position change, they seem to be all consistently changing hall state every 3 magnets.

The halls seem to be moving in a consistent pattern too with one on, then two, then one. Would this be correct for bipolar hall sensors? I do have another QS motor but unfortunately it’s a different connector type so I can’t check.

Did you try testing for resistance from each of the phases to ground? (Should be NO continuity)
Checking the controller for hall signal voltages?

This thread will give you some good information on testing with a multi-meter, both hall and phase circuits.
Bench testing as well as when connected to controller testing. As well as expected results in sequencing.

https://electricbike.com/forum/for...-motor-s-phase-wiring-hall-sensors-and-wiring



Regards,
T.C.

TommyCat said:

Did you try testing for resistance from each of the phases to ground? (Should be NO continuity)
Checking the controller for hall signal voltages?

This thread will give you some good information on testing with a multi-meter, both hall and phase circuits.
Bench testing as well as when connected to controller testing. As well as expected results in sequencing.

Testing BLDC motor's Phase Wiring - Hall Sensors and Wiring. - Electricbike.com Ebike Forum



Regards,
T.C.

Click to expand...

I am fairly certain I tested phase to ground continuity but will try again tomorrow. That looks like a good exhaustive guide to continue the troubleshooting with, thanks for sharing.

My pleasure, good luck.

Just an update, I have done some quick testing earlier and noticed something odd. The hall voltage for the yellow phase is reading at 6.1v, while the other phases are reading at 3.6v. From what I have read, the hall sensors ideally operate at a max 5v. This reading was taken while the controller was attached (probes fit down the side of the connector). Measuring from the controller, I see 3v coming from the two phases that were measuring 3.6, and 5v for the phase measuring 6.1.

I am unsure of the make/model of the hall sensors, but this seems a bit excessive? I am not sure how the overvoltage would affect the performance of the halls and potentially be the reason behind this problem though.

Feeling almost like a success, I managed to get a hall test to actually fail rather than timeout. I have been messing with some of the hall test parameters, including motor direction to try and get a pass/fail.

I thought I would take a video of the test which shows it is clearly getting stuck on one of the hall sensors as it seems to stop and then erratically "jump". At this point I am inclined to get some proper Honeywell SS413F halls ordered and start fresh so things can be ruled out. I have no idea what halls are in it at the moment.

C4m3Ltoe said:

The hall voltage for the yellow phase is reading at 6.1v, while the other phases are reading at 3.6v. From what I have read, the hall sensors ideally operate at a max 5v. This reading was taken while the controller was attached (probes fit down the side of the connector). Measuring from the controller, I see 3v coming from the two phases that were measuring 3.6, and 5v for the phase measuring 6.1.

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To clarify you have two voltage sources going to the hall sensors.
The 5vdc positive supply voltage (and corresponding ground) that powers the sensors operation. One wire each provides for all three sensors. (one wire for positive and one for ground) Hence the differences in voltage readings are odd.
And the hall sensors electronic signal voltage, one wire for each sensor.

I would recommend you take the readings again with the connector disconnected from the motor to verify on which side the problem is. Controller verses motor, and proceed from there.

Keeping in mind the known issue with the other set of hall sensors, I’m inclined to suspect the motor.

6.1v is very odd.

The hall sensors are all supplied by a 5 volt regulator from the Sabvoton. And the 5 volts is distributed to all of the sensors by internal wiring in the motor.

3.6 volts is usual for hall sensor outputs and there is a pull up resistor inside the controller for each hall sensor.

Are you sure you aren’t measuring 6.1 volts on the temperature sensor output instead of the yellow hall?

TommyCat said:

To clarify you have two voltage sources going to the hall sensors.
The 5vdc positive supply voltage (and corresponding ground) that powers the sensors operation. One wire each provides for all three sensors. (one wire for positive and one for ground) Hence the differences in voltage readings are odd.
And the hall sensors electronic signal voltage, one wire for each sensor.

I would recommend you take the readings again with the connector disconnected from the motor to verify on which side the problem is. Controller verses motor, and proceed from there.

Keeping in mind the known issue with the other set of hall sensors, I’m inclined to suspect the motor.

Click to expand...

I took readings from the controller and it measured 5v on the yellow, and 3v on the blue/green phases. Reading through old posts it seems this behaviour maybe normal for sabvoton. I am unsure how the voltage would elevate to 6v unless there is perhaps a short as you say

AGS said:

6.1v is very odd.

The hall sensors are all supplied by a 5 volt regulator from the Sabvoton. And the 5 volts is distributed to all of the sensors by internal wiring in the motor.

3.6 volts is usual for hall sensor outputs and there is a pull up resistor inside the controller for each hall sensor.

Are you sure you aren’t measuring 6.1 volts on the temperature sensor output instead of the yellow hall?

Click to expand...

No, I use the temp sensor as a reference point when measuring. It’s definitely measuring 6v at the yellow

C4m3Ltoe said:

No, I use the temp sensor as a reference point when measuring.

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I’d recommend using the ground wire as negative reference.

TommyCat said:

To clarify you have two voltage sources going to the hall sensors.
The 5vdc positive supply voltage (and corresponding ground) that powers the sensors operation. One wire each provides for all three sensors. (one wire for positive and one for ground) Hence the differences in voltage readings are odd.
And the hall sensors electronic signal voltage, one wire for each sensor.

I would recommend you take the readings again with the connector disconnected from the motor to verify on which side the problem is. Controller verses motor, and proceed from there.

Keeping in mind the known issue with the other set of hall sensors, I’m inclined to suspect the motor.

Click to expand...

TommyCat said:

I’d recommend using the ground wire as negative reference.

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Sorry, I meant as a visual reference. The hall connector that seems to be working is one that has random wire colourings. I am definitely reading from the negative > phase. The readings are consistent with the secondary hall connector which for some reason causes a “lack voltage” error on the controller

All of this is pointing towards a wiring fault.

Maybe it’s time to take the side cover off the motor and do some point to point wiring checks from the hall connector.

You can only access one set of halls by removing the side cover. To access the other hall set you will have to pull the stator out which will probably require a 3 jaw puller.

AGS said:

All of this is pointing towards a wiring fault.

Maybe it’s time to take the side cover off the motor and do some point to point wiring checks from the hall connector.

You can only access one set of halls by removing the side cover. To access the other hall set you will have to pull the stator out which will probably require a 3 jaw puller.

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I think that maybe the next step. We have had the stator out before so that’s not a problem, just a bit of a pain.

Any recommendations as to tests we can perform? Or will it be a case of stripping back all the white silicone and ensuring all the wiring is correct. The rewiring of the hall cable isn’t something I have personally been involved with but don’t mind getting stuck in.

I appreciate everyone’s advice so far!

It may also be worth noting that my friend removed the stator, and more importantly reinstalled it without any tooling. One thing that me and an “old school” electrician discussed over a beer was the possibility of some coil damage which is going to be a pain to determine.

Removing the stator without using a puller usually means bashing the motor axle against a block of wood on a concrete floor really hard.

I have seen YouTube videos of Chinese factory workers doing this and it’s frightening.

I have reinstalled mine without using a puller and it’s not so bad. Just need to keep your fingers out of the way.

AGS said:

Removing the stator without using a puller usually means bashing the motor axle against a block of wood on a concrete floor really hard.

I have seen YouTube videos of Chinese factory workers doing this and it’s frightening.

I have reinstalled mine without using a puller and it’s not so bad. Just need to keep your fingers out of the way.

Click to expand...

Two feet on the casing and pulling did it last time

Putting it back it is quite terrifying!

I don’t think I’m strong enough to pull it out on my own. I was a bit scared when I put it back the first time, because I wasn’t sure what was going to happen. But I’m ok with it now.

Just to update, I have had the wheel off and just took the side cover off to get a better idea on what’s going on.

I have managed to take readings across all hall cables and continuity is as expected. There are no shorts across any of the cables and the connectivity from the hub to the end connector all seems to be fine. I am going to keep at it in the hope to find something that maybe obvious but running out of ideas.

Does anyone have any further suggestions while the wheel is off?

One possibility that I can think of is that one of the hall wires is touching the windings below. Underneath the white silicone stuff they are bare cables with no insulation (which is how I probed them using a multimeter by simply prodding through the white stuff). While there is nothing obvious to suggest this, it would be an explanation for a secondary voltage source.

I have made up a test cable for the hall sensors to eliminate the inputs to the controller but still utilising the 5v supply from the controller, and used 1K pull up resistors from the hall outputs to the 5v supply.

If you get 6 sensible readings using a test lead for all of the hall sensors then the 6.1 volt problem must lay within the controller.