Motor gave out during ride - wheel hard to spin

[quickshot23]

I was riding today for about 3 minutes at a slow/moderate pace - 15-20mph and out of no where the motor just gave out

I checked all wires (all connected), temps (all cold), etc.

Everything checked out

I disconnected power and reconnected and the motor acts like it is disconnected

When I lift the back wheel and try to spin it by hand, it is very resistant - almost like im slightly holding the brakes

Any idea of the issue?

Pretty upset as I just finished the build and the motor just gave out for seemingly no reason

Thanks for your help

God Bless

 

[Drunkskunk]

Try spinning the motor with t5he wires disconnected. if it is easier to spin, the fault is the controller . if it remains the same, it's in the motor or wires to the connector.

If you determin it is the motor that is at fault, what sound does it make when you try to turn it? If there is a scraping noise when you try to turn, you likely have a magnet that has come lose or some other physical damage inside. otherwise it's probably a short in the wires. that can happen easily at the point where they exit the motor.

If the motor spun free while disconnected, then it's most likely that you popped some FETs. If you know your way around a soldering iron and have some basic electronic skills, it can be repaired.
If not, controllers are cheap. replace it.

 

[Tench]

If this is a new build, you say you have just finished it then I would suspect the wires have got damaged where they enter the motor. Does it have torque arms? The symptom of a motor being hard to turn is shorted phase wires. As drunk says, if it doesn't do it when you disconnect the motor then the fault could be in the controller. Is it a std controller or have you soldered the shunt and run more current through it?

 

[quickshot23]

After some testing, I ended up figuring out it is the phase wires - or some connection to them

I thought that disconnecting the controller power would stop the phase wires from interfering with the motor spinning

Apparently I was wrong

When I disconnected the motor, the wheel spun freely

What do I need to do to fix this?

Thanks alot - (I see you answering almost all my questions : )

God Bless

 

[Drunkskunk]

After some testing, I ended up figuring out it is the phase wires - or some connection to them

I thought that disconnecting the controller power would stop the phase wires from interfering with the motor spinning

Apparently I was wrong

When I disconnected the motor, the wheel spun freely

What do I need to do to fix this?

Thanks alot - (I see you answering almost all my questions : )

God Bless

Since the wheel spins freely once disconnected, the most likely cause is a bad controller. One or more of the MOSFETs inside is blown, causing a short. That short completes a circuit in the motor, and causes it to react like a generator. What happens when you try to turn the wheel is the generated power is trying to push back against you. The harder you push, the harder it pushes back.

99% sure the controller is at fault. but one last thing to check is for any shorts in the wires from the controller to the connector. If they are clear then it's time to contact whoever you bought the kit from and see about a replacement.

 

[quickshot23]

The controller being at fault is actually probably the best scenario

I have been posting in the "wanted" ads about a stronger controller anyway

I will confirm this and go ahead with getting a new and better one

Any recommendations? Lyen, em3ev - infineon, ??

Thanks again

 

[quickshot23]

Oddly enough, it may be the wiring harness - I tested each wires (green blue and yellow) for its resistance and only the yellow reported that I was even touching both ends

It appears the blue and green wires are shorted in the harness - Why would this happen?

How can I ensure that the controller is ok?

 

[dnmun]

the controller is not ok. the controller is broken. it is shorted across the mosfets.

 

[quickshot23]

The wiring harness in between the controller and the motor is not showing connection from one end of the wire to the other...

I havent tested the controller...

How are you sure its the controller?

 

[fechter]

If the wires going from the motor to the controller had a bad connection (open), you wouldn't get the turning resistance. Something is shorted.

From one motor phase wire to another, the resistance should be very low, so using a meter won't easily tell you if there is a short.

If there is a way to disconnect the phase wires right at the controller, that would tell you if the wiring harness was shorted. It is possible for a wire bundle to get pinched or overheat and melt the insulation, causing a short (not so common).

Check page 2 of this thread for controller testing hints:
http://endless-sphere.com/forums/viewtopic.php?f=16&t=44558&start=25

 

[quickshot23]

Here is an example of my awesome paint skills:



The way the bike is set up, I have a extra "harness" (as shown) in between the motor (circle) and the controller (rectangle)

I tested the wires at the ends of each color (as shown) and only the yellow shows that there is a valid wire

Any ideas?

 

[Drunkskunk]

If you have no continuity over that mid harness, then try the motor connected to the controller directly. If the mid harnes is in some kind of cover or sheath, you may have to take it out and inspect it.

If it was thin enough wire, it could have melted through and shorted out. Or been kinked and broken. or any number of possabilities that don't realy matter. if it's broken, it's broken.

 

[quickshot23]

What I am trying to figure out is, is it the harness or the controller...

I read this from "fechter":

To check for shorted FETs, disconnect the phase wires from the controller to the motor. Use an ohmmeter on low range (or autoranging) and measure from each phase wire to each power wire (6 combinations) and look for a low resistance. Any measurement that looks like less than a few ohms indicates a shorted FET. Normally, all the resistances should be in the megohm range, and may vary with time.

I am doing this test now...

I will report the results within a few minutes

Hopefully my budget multimeter does a good enough job : )

 

[quickshot23]

Interesting...

It appears its the controller - Heres why:

I did the FET test - Ohm meter from wire to pos and wire to neg

Each wire showed about the same until I got to yellow

Yellow to positive shows no resistance - 0.00 - This appears to be the issue

I want to get a new controller - so this should fix the issue, right?

 

[dnmun]

depends on what killed the controller. it is possible to replace the mosfets in the controller but it does require some skill, and good soldering irons, and solder wick and new mosfets. there may be a reason for it failing so you need to examine that before installing a new controller.

 

[quickshot23]

I did do the Shunt Mod - I was using a relatively high speed motor Crystalyte 406 uphill while pulling a child trailer

Im guessing it just pulled too much amperage and died

 

[dnmun]

what was the current reading on your cycle analyst?

 

[dogman dan]

Well, now we know why your controller blew. A better controller should allow you to melt your motor.

Fast wind, lots of weight going up hills, it's like hooking a 30' trailer to a VW bug.

 

[BikeFanatic]

Was that a crystal lyte controller? I had that same experience blowing fets right after a shunt mod, 40 amps wast oo mych for my controller. You need a controller with upgraded mosfets, here is an example.
I don't know what voltage you are running, but this controller goes to 40 amps and up to 72 volts. It is pricey, the 48 volt one is cheaper. I have the 48 volt one and it does off road,
carries cargo, doesnt get hot, very reliable. I thinkI paid 120 a year ago. Recomended vendor as well.

http://www.ebikes.ca/shop/ebike-parts/controllers/c7240-nc.html

 

[fechter]

Interesting...

It appears its the controller - Heres why:

I did the FET test - Ohm meter from wire to pos and wire to neg

Each wire showed about the same until I got to yellow

Yellow to positive shows no resistance - 0.00 - This appears to be the issue

I want to get a new controller - so this should fix the issue, right?

Yep, blown FET.
You might want to find out why your wiring harness doesn't ohm out properly too. If a phase wire had no continuity, it shouldn't cause anything to blow up, it just wouldn't run. A short between phase wires in the harness would blow the controller.

My guess is the load on the motor was just too much for the controller and it blew. Done it myself several times.

 

[Tench]

I will give a second recommendation for the 7240 from ebikes.ca, I have used a couple of these, no need to modify, they cope with 3kw no problem.

 

[quickshot23]

To clarify - the child trailer is all aluminum and weighs maybe 25lbs and I was pedaling and only half throttle

I understand I should have been running on the 4011 setting : /

The odd thing tho is, the motor never gets warm - I was doing full throttle for 25-30 mins and it was barely warm to the touch

Im assuming this means the motor can take more power

Question: Is the controller recommended equal in spec and capability as this: http://em3ev.com/store/index.php?route=product/product&path=38&product_id=82