Re: Pointseries gaps 'vs' other types
I appreciate your quick reply to the questions I posed on
rotary/series gap design. My hope was to save a bit of time and
gain from others experience in this area. Happy it is working! I
believe my next step will be to get some details on the G-10
phenolic material you mentioned(or equivalents), specifically the
ultimate tensile and yield strengths. I already have data at work on
glass filled composite plastics, used for molding structural parts,
since this was part of a project I started. This goes back a ways,
but as I recall the tensile strengths with short glass fibres was in
excess of 22,000 psi--I'll look this up tomorrow. I was considering
replacing some die cast aluminum parts at the time. Hope the G-10
stuff is equal to or exceeds this glass composite level. It will be
pretty straight forward to determine if a reasonable safety factor
is present or not.
>But the larger the diameter, the greater the mechanical stress and
>the greater the need for dynamic balancing. The pressures on a 10"
>disk's edges are incredible at 10,000 RPM. We are talking about
>several thousand PSI, depending upon material choices. (Am I
>making you ill yet?) It will probably be neccessary to get the
>assembly dynamically balanced for speeds in excess of 6,000 RPM.
>There goes a couple hundred bucks (ouch).
No, I'm not sick yet(green!!)--just becomes another item to review,
learn about and resolve. One of our products at work is a line of
servo motors which have provided some real interesting
manufacturing challenges. Specifically, we have rotor assemblies
that weigh up to 64 lbs. and do instant reverses at 5,000 RPM.
These units have magnet segments (12) attached to a 2.600" diameter
shaft--the customers would get real upset if one of these came
flying off at speed(none have). We use 2 plane dynamic balancing as
one of several steps in a process to prevent failures, so I'll save
that couple of hundred bucks and get the spark gap rotor assembly
precision balanced on one of the shop balancers. I better set some
quarters aside for buying the skilled operator some coffee--I'd
screw it up! The way I'll be mounting the disk to the shaft will
also allow me to adjust the assemly runout--Ihope to bring the total
indicator reading down to less than .005". This assumes the
purchased material is flat. If not, plan 2 will have to be
developed for T.I.R.
I don't plan on running this at an excessive speed until well
proven. I got many unanswered questions yet at this point with
sections of this coil project and I need to move with care. I'll
keep posting the results and when things start going together--I'll
make some photo's available if there might be any interest. I have
sure learned alot through others tests and trials that have been
posted, so I will make both my mistakes and successes available.
Again, thanks for the tips!