grunting at start - lyen sensorless

I have a lyen 6 fet mini monster sensorless controller that I've been using for over a year .

As of yesterday it has starting grunting and hammering the motor on start up, but once up to speed a bit - is still working fine.

I've checked all the connections and they are good.

Any ideas on what this might be and how to fix it?

Sure it's not a wiring issue? I had a similar thing with a phase wire rubbed the tire. It was down to one strand, so it ran smooth low load, but stuttered under load, like start ups.

A bad fet would be more likely to be running rough all the time, if it ran at all.

I seriously checked each and every connnection.

Funny thing is that if i baby the throttle on start up it runs almost normally. But I jam the throttle open like usual, and it gags. Especially with 2 kids on the back.

It also gags when I change grade from flat - to up hill.

I'm suspecting it is something like a bad capacitor on one of the phase legs that is not suppressing noise like it should be and causing general confusion in side there. (former statement an accurate depiction of my electronics mojo).

Well, when I rubbed a phase wire down to the last strand of copper, checking the plugs over and over didn't find it either. Got a cut wire at the hub? or a tire rub? Or melted a phase wire solder to the winding?

Just saying it doesn't have to be in the controller.

Well I can't discount the melted wire at the solder joint inside the motor possibility. But the reason I laced up this new motor (with bad halls) i had on hand was because I'd messed up wires at the axle just like you indicated. Xtracycle bag flopping over the unprotected wire at the axle.

duh.

I have exactly the same problem with an 18 FET controller I purchased from Lyen a month ago. Really bad grunting at startup, under load. Reverse pretty much useless. Baby the throttle and it starts somewhat normally, but start on any grade is impossible.
This controller runs very hot as well. With a 10a draw it can get too hot to touch. I've emailed Lyen but have received no explanation, only an apology that I didn't purchase an RS232 cable

Lyen sent a test video:
http://www.youtube.com/watch?v=4XYYAtLHTr4
the motor he tested was not under load.

I tried a 48v crystalyte sensorless controller on this motor and startup torque was closer to what one would expect for sensorless. Slight hesitation until the controller found the zero crossing then normal acceleration. Lyen's controller handles this poorly, almost to the point of hardware failure.

Hoping someone out there can provide some insight into this

If it always did this, then the most likely problem is either a bad contact at the halls or the phases plug, or simply having the wrong combination.

Look up how to find the right combo if it's not a simple plug issue. Do check the hall sesnsors too, it's possible you have one that doesn't work.

I have an Ecrazyman 6-FET sensorless controller which uses the same circuit board as the Lyen. When I first used the controller with my Bafang 250W motor I was impressed with its performance from a stop, especially considering I was using a freewheeling geared motor which are tougher to run sensorless than DD motors. Still, sensored worked better so I switched back to a sensored controller. Recently I dug out the Ecrazyman sensorless and used it for a few rides with the same motor. For whatever reason though the controller didn't work as well as before. To get moving smoothly from a stop I had to use a lighter touch on the throttle than I previously had to. I don't know the reason for it, it's just an observation. I changed to a KU93 controller (from BMSBattery) and it works amazingly well in sensorless mode.

-R

As I understand it, a sensorless controller uses EMF of the phases to establish rotation, phase(?) and my sense is that this link is tenuous at best.
At any rate, the reason I use a sensorless controller is that I damaged the Halls and it has allowed me to "salvage" the geared mini-motor and keep it in service.
Whether I'm using the Lyen or the KU63, there are ocassional start/sync issuses and it was clear to me to take it easy on the starts. Since I have 2WD, this means starting with the sensored motor first, rather than pedal first, consequently, it's NBD.
I would suggest that if you are using your Lyen with a geared mini-motor, that unless you are pedal starting hard every time, that you are abusing the Controller/motor system by hauling a trailer with kids in it.

dogman said:

If it always did this, then the most likely problem is either a bad contact at the halls or the phases plug, or simply having the wrong combination.

Look up how to find the right combo if it's not a simple plug issue. Do check the hall sesnsors too, it's possible you have one that doesn't work.

Click to expand...

These are sensorless. There are no halls