this sounds a lot like the problem I had with my Porsche hub which I made on my raggedy lathe. it was out 15/1000 on the dial indictor which means out 7.5/1000 as the high and low add . It turned out to be the key was to big and when I filed it down the hub came to 5/1000 on dial or 2.5/1000 . I had been thinking of getting rid of the clutch/presser plate and flywheel and using a lov joy coupler as is in my work truck . How big is the shaft ? Have you tried bolting it together 180* from were its at . Snip > I put the runout gauge on the flywheel, and measured almost > 40/1000's runout on the flywheel. I think this means 20 /1000 out which is to much I will be very interested to see what others say about this as I have just gone through it . I have not had to chance to rev it up since I fixed it ----- Original Message ----- From: <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Wednesday, August 21, 2002 10:38 AM Subject: Vibration, and the undocumented science of adapter design
> 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 > >
