E-bike motor spinning too fast

ibra2672

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Joined
May 24, 2022
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So the other day I was replacing my old controller for a new one. After connecting all the wires and testing the motor i noticed that it was much noisier than it used to be when I had my old controller hooked up to it and it was spinning way too fast (something like 70KPH with no load). With load there would be less acceleration and less smoothness compared to how it used to be but there wouldn't be the old 25km/h speed limit. I can easily reach 35+ km/h. My question is as follows: Is it alright to ride my e-bike with the motor like this or should I do something to restore it to how it used to be. Is it safe for long term use?

The e-bike motor is an old 250w hub motor
The new controller is rated at 350w 36/48v
 
The thing with going faster is that it also loads the motor more and since the new controller is more powerful than the old on you’ve got a risk to burn the motor. It could be alright if you take it easy and you check the motor temperature at the times when you know you’ve driven it harder than you used to. If it’s hot enough to burn your hand and it’s a geared motor then you need to back off a bit on the trottle and loading.
 
I'm wondering what causes the motor to spin faster than intended? I read it might be due to the phase wires being connected in the wrong sequence but I'm not sure.
 
I’ve installed hall sensors a few times but haven’t had a wrong combination run ok under load - it might run decent without load though.
If the combination isn’t correct there would be clear stuttering, rough sound and heating of the motor so you’d notice it.
 
If the physical layout of the halls vs the phase arrangment happens to create advanced or retarded timing (but otherwise correct signalling order) in one or more "wrong" phase/hall wiring combinations, you can get (sometimes significantly!) faster motor rotation than normal...but just like other altered-timing systems, it takes more power to do this and more heat is created. They often have much less torque than they should in this configuration, and may make significant noise under load (or even be unable to initiate rotation on their own but spin fine unloaded once started manually).


It's likely your controller has a same-color wire pair for "auto identify" or "self learn" or similar, that when hooked up will let the controller figure out the right phase/hall combination / timing. It works differently on different controllers, so if you have any info from the seller or manufacturer on this feature, follow that.
 
Thank you for the replies. They've been very useful to me.
I also found that self learning wire so now the bikes runs smoothly.
 
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