Do I need a puller for replacing hall sensors?

General Discussion about electric bicycles.
utsi   1 W

1 W
Posts: 57
Joined: Oct 11 2013 5:57am
Location: Norway

Do I need a puller for replacing hall sensors?

Post by utsi » Aug 25 2015 8:57am

Hi!

Bought a brushless motor in April this year: http://www.ebay.com/itm/2015-New-Style- ... TQ:US:1123

Recently it started acting up, and suddenly it stopped working at all.

Measured the hall sensors and seems that one is defective (gives constant 2V when turning the wheel). So I ordered new sensors from ebay, type SS41F. I ordered a chain whip and a shimano tool for removing cassettes, hope it fits.

My question is, will I typically need to take the motor fully apart or will I only need to remove one of the side panels? I do not have a puller and they don't come cheap where I'm from.

Thanks!

User avatar
Ykick   100 GW

100 GW
Posts: 5558
Joined: Nov 26 2009 6:10pm
Location: San Diego, California

Re: Do I need a puller for replacing hall sensors?

Post by Ykick » Aug 25 2015 9:08am

Main hurdle with freewheel tool will be the 14mm axle passing through it. I only need chain whip for cassettes not freewheel.

I've opened several DD hubs and never used a gear puller yet. I use a thin tool to separate the cover and then screwdriver or pry bar. Once it's moved a few mm then carefully stand on the rim with axle pressing on the ground to overcome the magnets. Carefully means don't bend the axle. Keep it straight and vertical as you push down against the rim. Don't need to remove both covers if you can reach the sensors.
Talent must not be wasted.... Those who have talent must hug it, embrace it, nurture it and share it lest it be taken away from you as fast as it was loaned to you.

- Frank Sinatra

utsi   1 W

1 W
Posts: 57
Joined: Oct 11 2013 5:57am
Location: Norway

Re: Do I need a puller for replacing hall sensors?

Post by utsi » Aug 25 2015 11:08am

Thank you very much!

I will not buy a puller then, and I'm keeping my fingers crossed that I can reach the sensors without taking the motor fully apart too - standing on the rim sounds like a nerve wracking exorcise :wink:

Eskimo   10 kW

10 kW
Posts: 503
Joined: Feb 25 2013 9:16am
Location: Helsinki, Finland

Re: Do I need a puller for replacing hall sensors?

Post by Eskimo » Aug 25 2015 11:39am

utsi wrote:Thank you very much!

I will not buy a puller then, and I'm keeping my fingers crossed that I can reach the sensors without taking the motor fully apart too - standing on the rim sounds like a nerve wracking exorcise :wink:
http://e-cruiser.blogspot.fi/2015/08/su ... uolto.html

Local engine tuning shop machined my freewheel socket to 14mm. I changed bearings.
Member of a 10 000 mile club
http://helsinkiheroes.com/

dnmun   100 GW

100 GW
Posts: 16190
Joined: Jun 09 2008 1:32pm
Location: portland, or and loveland, co

Re: Do I need a puller for replacing hall sensors?

Post by dnmun » Aug 25 2015 2:09pm

you can just drill the freewheel tool with a 5/8" drill too. or up to 3/4".

utsi   1 W

1 W
Posts: 57
Joined: Oct 11 2013 5:57am
Location: Norway

Re: Do I need a puller for replacing hall sensors?

Post by utsi » Aug 26 2015 12:34am

Thanks for the info!

I will see what arrives from ebay first, the freewheel socket or the chain whip!

This bike project is turning me into a handyman :lol:

User avatar
dogman dan   100 GW

100 GW
Posts: 35096
Joined: May 17 2008 12:53pm
Location: Las Cruces New Mexico USA

Re: Do I need a puller for replacing hall sensors?

Post by dogman dan » Aug 26 2015 5:29am

You don't need either of those tools. Just pull the cover off the motor, freewheel and all.

If you don't want to buy a puller, you can start with a knife, then thin screwdrivers, and using 2 or 3 tools slowly work the covers off once you have the bolts out. To finish the pull, you might need to use some small wood blocks to pry on, or the cover may slip off easy once you have it lifted some.

Once both covers are off, you can push the core out, by standing on the wheel with the wires facing up if they come out the axle tip.

IMO, you do need the core out of the motor to do the job. At the very least, you do need both sides open. The sensor is on one side, but the wires come from the other side. Easier to do the soldering, if you have some space you create by doing the soldering on the other side with more wire. You may want to add some wire to the halls on a bench, then make the final connection on the other side of the motor.

Others will read this, who have a geared motor. Opening them is different.

If it's a geared motor, then you will also need some snap ring pliers. But getting the core out of the motor will be easy. You might have to take a nut off the axle on one side, then the core will slip out.

utsi   1 W

1 W
Posts: 57
Joined: Oct 11 2013 5:57am
Location: Norway

Re: Do I need a puller for replacing hall sensors?

Post by utsi » Aug 26 2015 11:36am

Very helpful post, thank you very much!

Got both sides off on an old motor now, is it OK to use one of the sensors from it as a replacement or am I better off waiting for the slow mail from China and replace all 3 with new ones?

dnmun   100 GW

100 GW
Posts: 16190
Joined: Jun 09 2008 1:32pm
Location: portland, or and loveland, co

Re: Do I need a puller for replacing hall sensors?

Post by dnmun » Aug 26 2015 11:44am

yes, don't reuse an old one. they are so cheap don't know why you would destroy another motor to take them out of it. they are only about 50 cents.

utsi   1 W

1 W
Posts: 57
Joined: Oct 11 2013 5:57am
Location: Norway

Re: Do I need a puller for replacing hall sensors?

Post by utsi » Aug 26 2015 3:39pm

I wouldn't destroy a working motor for it, it is a defective one which I haven't been able to determine what's wrong with. Took it apart and couldn't see anything special, except some white dust all around the magnets everything looked fine.

What happened with it the last time was that it seemed that something was moving inside without the wheel moving when applying resistance.

It's just the motor without rim and spokes now, and I wasn't able to hold it back with my hand when I fired it up. It is tempting to get the repair shop to put a wheel on it again, but it's very expensive and I will be furious if it doesn't work. All I did today was to clean off the white dust inside. Smooth movement.

cwah   10 GW

10 GW
Posts: 4208
Joined: Jul 24 2011 5:42am
Location: Between paris and london

Re: Do I need a puller for replacing hall sensors?

Post by cwah » Aug 26 2015 4:44pm

Complicated
Help me find my stolen electric brompton: http://bit.ly/1a0vbBC and Bosch Sinus B3 http://bit.ly/1eV0WQz

utsi   1 W

1 W
Posts: 57
Joined: Oct 11 2013 5:57am
Location: Norway

Re: Do I need a puller for replacing hall sensors?

Post by utsi » Aug 27 2015 1:30am

cwah wrote:Complicated
Or just poorly explained, my English could use some improvement..

Any ideas on how to troubleshoot my old motor with working sensors?

dnmun   100 GW

100 GW
Posts: 16190
Joined: Jun 09 2008 1:32pm
Location: portland, or and loveland, co

Re: Do I need a puller for replacing hall sensors?

Post by dnmun » Aug 27 2015 6:22am

you have a direct drive motor that would not turn with the controller designed for the motor? this is the one you said is defective?

the motor that you bot the hall sensors for is functional except for the one hall sensor you identified as not toggling? you have ordered replacement hall sensors for it i am assuming from your comments about slow mail.

so now you would like to diagnose what causes the other defective motor to not work?

User avatar
dogman dan   100 GW

100 GW
Posts: 35096
Joined: May 17 2008 12:53pm
Location: Las Cruces New Mexico USA

Re: Do I need a puller for replacing hall sensors?

Post by dogman dan » Aug 27 2015 6:28am

Uhh, I could be wrong but,,, on your old motor, if the phase wires were touching each other while you have it unplugged from the controller, it would resist like hell. But nothing wrong with it.

Not sure if that was what you have, but the first time I saw this effect, it shocked the hell out of me and I did not know what it was.

Eventually, or even right away, you might want to get a motor /controller tester off ebay. Cheap, and a real time saver to use the tester and be able to say, Oh, it's the controller, or oh, it's the throttle. and if all tests good, Oh, its the plugs or wires.

Until you know what's wrong with the old motor, I'd leave the halls in it alone. Just because soldering on those tiny things is so hard for me. Too small to see, I don't solder that great, etc. So I would not want to do it twice.

utsi   1 W

1 W
Posts: 57
Joined: Oct 11 2013 5:57am
Location: Norway

Re: Do I need a puller for replacing hall sensors?

Post by utsi » Aug 27 2015 8:45am

dogman dan wrote:Uhh, I could be wrong but,,, on your old motor, if the phase wires were touching each other while you have it unplugged from the controller, it would resist like hell. But nothing wrong with it.
This was not the case for me. The motor was running just fine without resistance, the wheel spinning in the air. But once I put it down and sat on the bike, it was not able to drive forward. Something seemed to be moving inside the motor but the wheel was standing still. Someone suggested to check if the magnets were loose, that was not the case. I'm still using the same controller with the new motor so it must be the motor.

I will check out the motor / controller testers on ebay, thank you!

John in CR   100 GW

100 GW
Posts: 13872
Joined: May 20 2008 12:58am
Location: Paradise

Re: Do I need a puller for replacing hall sensors?

Post by John in CR » Aug 27 2015 11:41am

Mark both covers and their position on the rotor ring. I use one dimple on one side and 2 on the other. That's so you can put the covers back on exactly as they were.

Make sure it's not just a connector or wire issue before opening.

Make other improvements to the motor while you have it opened, so it only gets opened once. If a hall is defective, replace all 3 with better quality Honeywell's. Upgrade the wiring harness with thicker phase wires. Check the hall wires themselves, because often people replace a hall only for the problem to come right back due to a short in the hall wires. If the motor got hot enough to kill a hall, then it's just as likely to have gotten hot enough to damage the insulation on the hall wires. Put a coating on the ends of the stator lams to prevent corrosion. Replace the bearings with good quality bearings.
Install a temp sensor and the wires for it in your reworked motor harness. Consider cooling mods while you have it opened.

utsi   1 W

1 W
Posts: 57
Joined: Oct 11 2013 5:57am
Location: Norway

Re: Do I need a puller for replacing hall sensors?

Post by utsi » Aug 28 2015 5:45pm

Thank you for your advice John! Don't know where to get quality bearings, can they be bought from China?:)

I'm considering trying to build a wheel myself. What thickness and length of spokes are typically used for this kind of motor and a 26" rim? I would get a rim with double walls, but should it be as wide as possible or any other considerations?


One thought on the side: Are the rotors usually the same size in these motors? Maybe I could try the old rotor in my new wheel if it fits?

User avatar
Ykick   100 GW

100 GW
Posts: 5558
Joined: Nov 26 2009 6:10pm
Location: San Diego, California

Re: Do I need a puller for replacing hall sensors?

Post by Ykick » Aug 28 2015 6:33pm

Alex DM24 is a good, cost effective rim. I use 13/14ga butted spokes from Danscomp USA (must phone and ask for the butted spokes, 50¢ ea last time I bought. Probably not cost effective for you outside of USA.

Spoke length is determined with know rim/motor flange measurements and online calculators. Try the one on eBikes.ca
Talent must not be wasted.... Those who have talent must hug it, embrace it, nurture it and share it lest it be taken away from you as fast as it was loaned to you.

- Frank Sinatra

utsi   1 W

1 W
Posts: 57
Joined: Oct 11 2013 5:57am
Location: Norway

Re: Do I need a puller for replacing hall sensors?

Post by utsi » Aug 29 2015 5:38am

Thanks, Ykick!

I opened the new motor now and started measuring the different wires to check for connection issues. I measured the one from the faulty sensor and there was contact. But wait - it was also contact from the same wire to everywhere! It turned out that the repair guy may have been handling the wires carelessly, because upon inspection it turned out the insulation had been compromised on the wires where they go into the hub... Applied some liquid tape now and will test the halls again.


Update: It wasn't the short's fault alone, the sensor is broken. On the positive side I've learned that taking the motor apart isn't so scary after all.

Also tried to use the rotor from the old motor. It fitted, and the wheel was running smoothly, but once I tried to ride the bike there was scary sounds from the motor and it didn't drive me forward after a couple of meters :( Is it garbage or are there other things to test for once you know the sensors and the wiring works?

User avatar
dogman dan   100 GW

100 GW
Posts: 35096
Joined: May 17 2008 12:53pm
Location: Las Cruces New Mexico USA

Re: Do I need a puller for replacing hall sensors?

Post by dogman dan » Aug 29 2015 6:37am

Are they identical motors? If not, you may just need a different wire order for it to run on a particular controller.

utsi   1 W

1 W
Posts: 57
Joined: Oct 11 2013 5:57am
Location: Norway

Re: Do I need a puller for replacing hall sensors?

Post by utsi » Aug 29 2015 6:44am

I'm afraid I'm not that lucky. The old motor is the one that came with the controller I'm currently using, so the wire mapping is straight forward.

utsi   1 W

1 W
Posts: 57
Joined: Oct 11 2013 5:57am
Location: Norway

Re: Do I need a puller for replacing hall sensors?

Post by utsi » Sep 04 2015 4:02pm

The sensors arrived yesterday.

Opening the motor was easy, so was getting the stator out, just pushed the rim down with my hands. The difficult part was soldering the sensor. Also, tried to insulate with liquid tape first, but it wasn't enough. Had to use heat shrink tubing.

I will take the bike for a test ride tomorrow if the weather permits it.

Thank you very much for all your support, without you I would have given up!

User avatar
Ykick   100 GW

100 GW
Posts: 5558
Joined: Nov 26 2009 6:10pm
Location: San Diego, California

Re: Do I need a puller for replacing hall sensors?

Post by Ykick » Sep 04 2015 4:17pm

Yeah man, that’s how it works! Ask questions, get in there and you can see what needs to be done. Worst that can happen is you still have a non-working motor but it sounds like you brought it back from the junk pile!

Your sensors glued into the laminations? I shrink wrap the leads too. Dress everything sensibly, couple tie-wraps, good to go.

Sometimes they’re mounted on a PCB but it’s all fairly basic stuff. Definitely one of those skills you do 5-6 times it can become fairly quick & easy.
Talent must not be wasted.... Those who have talent must hug it, embrace it, nurture it and share it lest it be taken away from you as fast as it was loaned to you.

- Frank Sinatra

utsi   1 W

1 W
Posts: 57
Joined: Oct 11 2013 5:57am
Location: Norway

Re: Do I need a puller for replacing hall sensors?

Post by utsi » Sep 04 2015 4:45pm

Yes, the sensors were glued into some holes in the metal. Had to use a lot of heat and a small screwdriver to get the broken one out. I'm a little ashamed to admit it, but I only changed the broken one instead of all 3 :oops: Doing all seemed a little risky the first time.

What worries me now is that the spokes the repair guy used are ordinary spokes, and some of the heads have gone deep into the holes on the motor. I think this could be a problem since it causes the spokes to bend. In general, do people here do their own spoke replacement or is it this typically done by professionals? This stuff is a pretty big expense and a pain in the butt because it means to get the wheel off every time.

User avatar
Ykick   100 GW

100 GW
Posts: 5558
Joined: Nov 26 2009 6:10pm
Location: San Diego, California

Re: Do I need a puller for replacing hall sensors?

Post by Ykick » Sep 04 2015 4:49pm

Sounds like the spoke heads need washers or why I use butted 13/14ga spokes.

I think most of us who stick with this learn to lace our own wheels. Saves a bunch BS dealing with a non-standard bicycle wheel. That get’s expensive and you don’t always receive the best result. Lacing 1 cross motor wheel is not that hard. Starting with decent components and practicing truing on any bicycle wheel will help you build a wheel.
Talent must not be wasted.... Those who have talent must hug it, embrace it, nurture it and share it lest it be taken away from you as fast as it was loaned to you.

- Frank Sinatra

Post Reply