Submerged motor, now malfunctioning!
After having to wait through a heavy, but not unusually heavy, thunderstorm, I was riding home from work when, topping a rise suddenly found myself facing a flooded dip in the road - going too fast to stop. It has never flooded like this before. I was left with no choice but to power through the 2 to 2.5 feet of muddy water hoping to get out the other side before something got ruined.
No such luck. The motor now will not start turning until given an initial spin, thereafter it runs roughly and noisily, at slow speed, getting smoother (nearly normally) at top RPMs. I rode it slowly home (about 5 miles) in this condition - maybe not a good idea.
I dried the wiring connectors and checked for evidence of water intrusion into the controller. It does not look like water got in the controller.
The only fully submerged item was the motor, so my best guess is bad hall sensors - maybe just temporarily until they dry out?
Ideas?
Matt, I recall that you once disassembled an e-max motor? Any tips?
Thanks for any advice.
Paul D.
Not sure it's any help but I think the Hall sensors we use are: Honeywell’s SS41 and Infineon’s TLE4945L. I'll check with Erik on what was involved in replacing them - I don't recall it being too terrible.
Good luck!
I got it fixed.
The motor resumed working after being left to sit in a dry garage for a couple hours. So it seems the hall sensors are fine, but water on the signal leads caused a poor signal.
The problem would certainly recur unless all the water was removed from inside the motor case, so I removed the motor/wheel and removed the side plate that holds the left axle bearing and poured a couple teaspoons of trapped water out of the case. I left the case open for 36 hours to dry, and reassembled the side plate - using silicone sealant to seal the plate to the motor case. I always wondered what the hex-key plug on the left bearing spacer (where the wires enter the motor) was for. After this mishap, it's function became obvious - it is for attaching a grease fitting and filling the spacer and bearing recess with grease for water resistance - something the factory didn't do. So I added a grease fitting and greased it. The bearing recess on the brake-drum side of the motor was also filled with grease, and a rubber garden hose gasket slid down the axle to the recess to serve as a grease seal.
I don't intend to make a habit of it, but I think the motor can now withstand brief dunkings in water over the axle height.
The motor continues to exhibit some problems since it's dunking. There is a sporadic stumble - only in low RPM, high motor-current situations. It seems that something about this conditions is causing a bad signal from in one of the hall sensors. Perhaps moisture and degraded wire insulation? Bad hall sensor? The possibility of water in the controller was never excluded either.
It looks like I might have to disassemble the motor to have a look. Matt or anyone else, any advice on motor disassembly? I assume a puller tool is needed to extract the armature from the case. Any advice would be appreciated.
Hi Paul,
when i was dis-assembling my motor, i used a shop press to push the motor apart.
that's how my local EV workshop pushes apart all permanent magnet motors.
Matt
Hi Paul,
sounds like a hall sensor failure (or if you are really lucky, just an external shorted hall sensor)
when i last had this problem, i replaced the original hall sensors with those from another (mechanically) broken motor.
I was not able to identify the original part number.
When i go back to the factory tomorrow, i will ask if they know what specific hall sensor was used in the motors for the emax sport.
i remember also seeing a motor among old-new stock for the emax sport.
ill ask for a price aswell.
cheers,
Matt