I am all for the bell housing being done first. We have needed one
of those for the last ten years. We also need to figure a way
of locking the input shaft seal in from the back side.
IMHO Tracy does it this way to provide support for the helical gear
thrust bearing. Here is a dwg of the plate looking at it from
the back side. The seal is pressed in from the back side of the plate.
Apparently there is very little room before the input shaft spline.
The seal seems to be working out of the bore for whatever reason. Maybe
high pressure in the gear box.
BTW while we are at it we could put in a torque meter that would measure
the helical gear thrust. There would be more room if there was
another way of attaching the helical gear to the input shaft instead
of a pin. Perhaps it could be broached and silver soldered to
a spline on the input shaft.
Paul Lamar ...No rotor no motor.
Why not put in a strain gage? Takes up almost no space. My son found one
for
$200, and it includes a meter.
Doc Custer
Retired Software Engineer and sometime Audiologist
Is it a torque meter type? Is it new? Got a picture?
--
Paul Lamar ...No rotor no motor.
Doc,
Timely Post. I was down at our test facility two days ago and notice we
have a torque meter built-into our 5 kW electric motor dyno. The engineer
told me it worked using several photo optical devices. He said strain
gauges are OK but since their resistance varies with temperature we would
need to have some type of circuit to compensate for it.
Optically I don't how it works. Probably measuring the angle of light
refraction.
Doug Fir
You can measure a very small amount of shaft twist with two optical devices
separated by a finite distance along the length of a shaft with small flats
ground in strategic places.
Here are some more ideas for the annular pressure cylinder trick.
This is widely used in turbo prop engines to read out torque.
Paul Lamar ...No rotor no motor.
Paul,
Not sure I believe my eyes. Is Tracy using a stack of Torring bearings,
three each for clearance control? Sure wish I had know this when I was in
the automatic transmission rebuilding business.A stack of 3? Thanks,
Boberrorusa
Not clearance control. Takes the helical gear thrust.
It is a cheap way to go. High RPM exponentially reduces the capacity
of needle thrust bearings. Needle thrust bearings don't like high RPM.
Three bearings back to back cut the individual RPM by 1/3rd. Tracy replaced
the single roller thrust bearing with this system. Same as late model Ross
PSRU's.
--
Paul Lamar ...No rotor no motor.
Paul
There are several other ways to do it as discussed on the eng tips forum for
the few of us who are running straight geared PSRUs. BTW I highly recommend
this forum.
http://tinyurl.com/26nwbw
One person recommends Binsfeld.com.
Two devices here. I am waiting for a price quote on the permanent unit now.
If anyone suspects they are encountering torsional vibration or want to
verified it, one engineer uses a magnetic or optical encoder with a
frequency to voltage converter to measure torsional vibration as angular
velocity. In our PSRU applications this probably entails mounting a multi
tooth sensor plate on the output side of the torsional absorber. Perhaps on
the prop flange.
Doug Fir
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