Mark, Make sure the hub doesn't wobble together WITH the flywheel, because if the splines have some slack, it might. The hub alone won't wobble with reasonable balance, but if there is a slack in splines, it will once you bolt heavy flywheel to it.
Can you feel movement of the hub relative to motor shaft splines if you grab the edge of the flywheel and push back and forth in coaxial direction? Victor [EMAIL PROTECTED] wrote: > > Slowly wrapping up the conversion of a 99 Ranger to electric, using > Metricmind's AC drive system. > > The first time the truck was assembled it had a noticeble vibration > whenever the motor was spun, even with the transmission out of gear. I > didn't think it was too severe and drove the truck for a few days. A > missed shift caused me to accidentially spin the motor to its rev limit at > 7000rpm, and quite suddenly the vibration got a lot worse. > > Disassembly of the adapter showed the 4" long motor shaft to be bent > (almost 40/1000's of an inch). Also I found several noticible gashes on > the inside of the bell housing, and the clutch slave cylinder thrust > bearing had cut a groove into its shaft. > > Took the motor apart and sent the rotor/shaft to a propeller machinist. > He used a tool meant for straightening bent prop shafts, and brought the > motor shaft to within 3/1000's of true again. So now I am putting > everything back together, and taking extra care to balance and true > everything. > > Here's my problem. The face of the hub attached to the motor shaft is > perpendicular to the rotation of the shaft to within about 2/1000's of an > inch and the centering ring is concentric. Spin just the hub up to 7000 > RPM, everything is smooth, no vibration. I attached the flywheel and > pressure plate (which were professionally balanced) and the whole system > gets a scary vibration, shaking the truck noticibly before even getting it > to 3000RPM. I put the runout gauge on the flywheel, and measured almost > 40/1000's runout on the flywheel. > > Figuring the flywheel warped (it had been lightened to about 1/2 thick) I > replaced it, had the new flywheel resurfaced and balanced... same problem, > the face is out of true by about 40/1000's and it vibrates heavily. > Unfortunetly I have not been able to have the balance shop do the > hub/flywheel/pressure plate together, becuase his balancing arbor won't > fit inside the splined portion of the hub (the Siemens motor has a splined > shaft) > > Some possible thoughts: > 1. The Siemens motor has a shaft almost 4" long, with the hub attached to > that, and the flywheel hanging about 1/2 beyond the end of the shaft. > Victor says the motor shaft should have no issue with 20lbs of flywheel 4" > from the motor bearing, but the shaft has bent once already for unknown > reasons, and everyone who looks at it gets nervous. > > 2. The balancer isn't balancing, or the machinist that resurfaces the > flywheel isn't verifying that the front and rear faces are perfectly > parallel. > > Any other ideas? Is 40/1000's acceptable for a flywheel face? Should I > shop around for a balancer with a smaller arbor on his machine? Or make > an adapter that would convert from the spline to something an arbor could > grab? > > Thanks > Mark Farver > Austin, Texas
