Motor Jerks at Low Speed and Under Load

T

tmort

10 W
Joined
Jul 3, 2008
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83
I have an ebike that I am putting together. It uses a Crystalyte 72V 40A Speed Controller and a Phoenix Brute motor.

I got the motor and the controller from two different sources. The motor had trailer connector and the controller had Anderson connectors. I matched colors and switched the motor to Andersons.

I thought the controller I purchased was an instant start type but I'm not sure.

I'm finding that the motor doesn't want to start without some help and it shudders and jerks at low speeds and under load.

I found another post that seemed to have this problem and blown mosfets was suggested, but, this is all new stuff.

Anyone have any advice?

TIA
 
Tried switching yellow and blue leads both places. Wheel didn't start when throttle applied off the ground. I did coast a little and applied throttle for just a second and it still jerked
 
Are the controller & motor new?

I would try all possible wire connections (not red/blk on halls tho). I was searching her for a definitive thread on controller/motor wiring combos but couldn't find it. You might add 'brute' and other specific terms to the query.

Edit. Found it.

Sometimes I've had the combos right, but one will pull out slightly, causing poor contact and have same effect.

It could be something else, but it's always been the connections for me...
 
All I could find was that the colors match up for a C-lyte motor to a C-lyte analog conntroller. That is what I have, I'll double check the colors.

I have a cycle analyst and the speedometer function seemed to work properly, wouldn't a hall sensor problem affect the speedometer?
 
I'll check the connections and take some pictures next week.

One more thing:

Before I had my battery I hooked the controller up to a small 48V AC/DC adapter to check some things. While this was connected I moved the throttle accidentally and the wheel tried to start. Could starting the motor with not enough power cause a problem?

Also, both the controller and motor are new. They are at least a year old because it has taken me that long to get the cash to get a LiPO4 battery.
 
I got a chance to take a look. The power leads for the motor and controller both had colors that matched.

Looking at the hall effect connectors it looks like:

Motor Controller

Brown Red
Black Black
Green Brown
Yellow (still switched from previous suggestion) Blue
Blue Yellow

I ran out of time and light but will switch the yellow and blues back and try switching the brown and green wires.
 

Attachments

  • connectors.zip
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I confess I've got no C-lyte experience at all, so considering both are from the same manufacturer, I'd rewire yellow & blue to original places. (Weird that the Browns don't match up tho...)

I wouldn't move the black/red though!

Sorry, maybe someone else can be more help. My problems have almost always been poor connections!

Keep up the spirit. You're almost there. I can't believe you've waiting a year! I'm rooting for you!!

It can be tiring, but keep searching the forum!
 
Did the motor seem to have good power after you got past low speed (don't try if you don't already know)? If you purchased the motor and controller separately from different sources, it's very likely the wiring configurations don't match. Don't try riding it until you get it right, and only apply partial throttle when trying to get it right with the wheel off the ground. Wrong combinations can result in very high currents that can damage the motor or controller. Your symptoms are a bit unclear, so most likely a wiring problem or a bad connection somewhere.

WRT trying wire combos never switch more than 2 wires on each attempt. With a given phase combo, there is one good combination of hall wires of the 6 possible. What you don't know is if it's forward or reverse. If it's reverse, then I find trying different hall combos easy by sliding the spades out of the connector to easily swap 2 each time in the female side of the connector. Of the 6 combos, the smoothest spinning least sound is the good one. Try all 6. If the good one is reverse, then swap 2 phase wires, any two, and go back to the halls and your proper combo will be one of the 6.
 
I left the phase wires alone and I left the

Motor Controller

Brown Red
Black Black

seeing as how sometimes brown is +5 volts

and tried the different permutations of

Green Brown
Yellow Yellow
Blue Blue

and none of them spun the wheel with it off the ground.

Before I try more combinations I thought I would check back with you all.

I also measured the voltages coming off the different leads from the controller. I assumed black was negative:


Red - Black 4.3V
Brown - Black 5.0V
Blue - Black 4.8V
Yellow - Black 5.0V
 
so is it not spinning at all? or is it still jerking, making noise? if not, does the controller have a switch?

any c-lyte people know if there are other connectors that need to be jumped or whatever?

i've never measured the voltage off the phase wires, so can't help you there.

finally, where do you live? maybe somebody nearby can help. it's so hard to diagnose w/o seeing it...

but yeah, i would say keep trying combinations!
 
It's not spinning at all with the wheel off the ground. I could get it to run with jerking it I got it started by pedeling first, but, my connectors don't have any spades on them, so to easily try different combinations I soldered some jumpers with alligator clips to one side of the connectors. This doesn't lend itself to riding.

Yes the controller has an on off switch and it is turned on. It has a pilot lamp to indicate that it is turned on.
any c-lyte people know if there are other connectors that need to be jumped or whatever?

The voltage measurements are from the controller side of the hall effect wires.

I'm in west Michigan

I thought I heard that you want to be sure not to connect the +5 volt and the ground to the wrong terminals on the hall effect bundle
 
BTW, I also put contact cleaner on the connectors before I tried the different combinations
 
tmort said:
It's not spinning at all with the wheel off the ground. I could get it to run with jerking it I got it started by pedeling first, but, my connectors don't have any spades on them, so to easily try different combinations I soldered some jumpers with alligator clips to one side of the connectors. This doesn't lend itself to riding.
Click to expand...
Don't ride it! When you do a new combo and then test the throttle, does it make an unhappy sound? If not, spin it a bit with your hand.

From my limited understanding, the halls tell the controller what position the magnets are in, so it can 'fire' current through the phase wires in the proper order to spin the tire. When the order of halls/phase wires is NOT correct, it won't spin properly, and will pour current into the motor with nowhere for it to go, and that's NOT GOOD - so no riding until it spins nicely.

For the same reason, it's not good to open the throttle wide when the wheel is off the ground. You should know when the combo is right, and test gently until you get it.

I don't know what would happen if it were stressed too much under an incorrect combination. Anybody know what would pop?? It may be that it's gotten to that point, in which case you're not going anywhere, even w/ right combo, until you repair a hall or something. And it's not a repair I'd want to do, so my sympathy goes out to you.

Not a great intro to ebiking!

It's not a great solution, but considering alternatives, since you're not exactly in an urban area :D , you could try to sell the motor and get a new one... Some people have listed stuff in the for sale thread only to get help fixing them!

Anyone got more ideas what he can do to troubleshoot this??
 
I found a couple links on the subject of diagnosing controller/motor issue:
http://www.bikeforums.net/archive/index.php/t-330996.html
http://ebikes.ca/troubleshooting.shtml

I measured some voltages and resistance on the hall bundle, but, am not sure how to interpret the results:

Power Unplugged, Hall Bundle Unplugged

Red - Black 4.3V

Power Unplugged, Hall Bundle Plugged

Red - Black 4.3V

Yellow - Black 18mV - 5V
Blue - Black 19mV - 4.5V
Green - Black 19mV - 5V


Resistance

Power Unplugged, Hall Bundle Unplugged

Yellow - Black infinite
Blue - Black infinite
Green - Black infinite
Brown - Black infinite

I think the fact that all of the hall sensors have essentially the same reading is a good sign for the motor. I'm not sure about the resistance values though.

I read in one of the other posts that the voltage between red and black on the controller side should be 12-14V and with it plugged in it should be 6-9V.
 
the only way to check if the halls are working is if you can measure the halls while plugged into the controller. or if you power the halls using a 9V battery. that would be the black and the red wires on the hall bundle. now if you check the hall signals (yellow, green, blue) the signal should toggle between less than 1V and something over 4V as you rotate the wheel by hand. this is the action of the hall sensor switching on or off depending on whether there is a North or South magnet pole close to it. any tests of the hall signals with a stationary motor or with the hall bundle unpluged is pretty much useless. all you can check is if the controller is supplying the power to the hall sensors thru the red and black wires.

all of these tests including very pretty pictures are in the technical reference area of this forum. check the one titled "How to Determine the Wiring for a Brushless Motor"

the hall sensors turn on and off in a pattern. this pattern always follows the same sequence as the motor spins. the controller recognises this pattern and turns the 3 heavy output wires on and off in a similar sequence in such a way that the motor turns away from its present position. as the motor rotates, the pattern of the 3 hall sensors will change and a different pattern of power is applied to the 3 heavy wires so again the motor rotates away from it's current position. and so on.

if the pattern of halls is not changing in the correct seqence, the power applied to the 3 heavy phase wires will also be in the wrong sequence. instead of pushing the motor away from the current position it could actually lock the motor into that position. if left locked for too long the power switches inside the controller (called FETs) can burn out.

another situation would be if the sequences was that in step one the motor moves to position 2. once at position 2 the motor moves back to position 1. back and forth between the 2 positions. this one is not as dangerous because the switches are tuning off and on giving them an opportunity to cool off.

a third is where the new commanded position is too far away from the current position. in this case the motor may continue moving once you give it a shove but it will not move quickly or with any power. while stopped if the throttle is on the fets will also be on and can burn up.

if you suspect your controller is bad this thread "Crystalyte Controllers - Repair and Modification information" has some good tips on testing the controller in the first few pages. the information is general enough that it could apply to almost any controller.

rick
 
I've done some of those tests but still don't know how to interpret the results.

I did the rollback test where I rolled the wheel backwards with the controller both on and off. There wasn't much resistance in either case and it was the same.

I did the test of the FETs and when I took the resistance between each of the phase power leads with each of the controller power connections I got a consistent reading of 9-10 K Ohm. In the thread it says it should be in the Mega Ohm range???

When I test the power at the hall sensor red and black leads both with the controller connected and unconnected I get 4.3 volts instead of 12-14. When I rotate the wheels and measure the voltage between the hall phase leads and the negative on the battery I get:

Yellow - Black 18mV - 5V
Blue - Black 19mV - 4.5V
Green - Black 19mV - 5V
 
on the hall leads is it a steady 5V? or does it flick from 0 to 5V and back like as if switch turning off and on when you rotate the wheel? that is what it should do. if does not than the halls are buggered. if they stay at a constant 5V as you turn the wheel by hand they are also buggered. i think you are consistently missing the part about they should be turning off and on. you keep on saying something about -5V but forget to mention or not making it clear whether they are turning OFF AND ON or STAYING AT A STEADY 5V.

many controllers only supply 5V to the hall sensors. some supply a higher voltage. but hall sensors can operate with a wide supply voltage range. so as long as the red wire is at least 5V don't worry about it.

that is the first thing to determine.

rick
 
the hall leads go on and off

The voltage between the hall red and black is 4.3
 
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