Subject: RE: Aberdeen Bridge Test
Date: Mon, 31 Jan 2000 10:02:45 -0600
From: "Kaufman, Tom" <Tom.Kaufman@mts.com>
To: "Larson, Rod" <Rod.Larson@mts.com>

Rod:
Accumulation:  Here are my thoughts.
We quoted 200 GPM pump, but I upgraded to 250 GPM.  I would like to run
mainly on HPS flow, and use min. amount of accumulators.  I have planned
(one on each side) 5 or 10 gallon accumulator attached to hardline.
When looking at loading curves that you did, it appears that about 2
actuators on each side (4 total) are running at the high velocity at any
one time.  As one actuator hits peak load, the actuator next to it is
already is into the high velocity part of the curve.  The waveform is
basicly triangle with rounding top & bottom.  The larger area on
compression side, will mean that more cu. inch of oil will need to go
into the return stroke than the tension stroke.
We won't have sufficient accumulator capacity to store energy from start
of crossing to the middle of crossing.  I believe the process of slowing
the crossing rate down for middle section and speeding it up at ends
will work.
Tom K

> -----Original Message-----
> From: Rod Larson [SMTP:rod.larson@mts.com]
> Sent: Saturday, January 29, 2000 2:47 AM
> To:   Kaufman, Tom
> Subject:      Re: Aberdeen Bridge Test
>
> Tom,
> OK for 3rd 497 rack for 497.15s.  We did 16 valves for NIED S/V
> Controller
> and had room.  I will ck my layout that I just sent to Don Johnson,
> but I
> think it will still work.  I did not specify which Temposonic to use,
> cuz
> the analog can plug directly into ADDA Card (A/D Converter) or Digital
> one
> can go to special ADDA Card.  The analog is much easier cuz it could
> have
> 18 channels on 3/4 of one adda card.  If we use digital, we can ONLY
> get 8
> channels per ADDA Card.  Therefore it would require 2 extra ADDA cards
> and
> Tempo interfaces (about $3,000).  You decide.  I do not think that we
> will
> be using the stroke for control except for set-up; mainly read-out of
> position for max deflections.  Ck w/ David Chua cuz he used an analog
> Tempo
> but I do not think he had any problems that would reflect a problem on
> a
> low frequency system.  (so, for the moment, I vote analog).
>
> Does the 90 GPM valve present a problem for the pump???  Or, can we
> get
> enough accumulator to be ok.
>
> Rod
>
> At 05:51 PM 1/28/00 -0600, you wrote:
> >Rod:
> >The loading curves you did for me have an important piece of
> >information.  It shows the rise time(velocity) needed for each of the
> >actuators.
> >This servo-valve flow is then easy to find.  My conclusion is that
> the
> >60 GPM Moog valves would be too small.
> >They would almost meet the flow for tension side, but the flow out of
> >the compression side would cause too high of a pressure drop over the
> >S/v.  (If we slowed down the time for center cycles, we push the
> higher
> >velocity cycles outward toward ends(with shorter strokes).  We still
> end
> >up with higher velocities than the 60 GPM valve can handle).
> >
> >Therefore I would like to use the normal 90 GPM 256.09.  I did my
> best
> >to check the costs, and it looks like we can save over 10K by using
> the
> >bigger valves.  It means that you will need to use (18) 497.15 valve
> >drivers, and this adds one more 497.01 chassis.  I looked at a normal
> >vertical rack, and it looks like we still have plenty of room for (4)
> >497.01 chassis and the 498 box.  Let me know if you see something
> that
> >is a show-stopper.
> >On Monday next week, I plan to give the actuator group the go-ahead
> to
> >complete BOM's with the 256.09 valve.
> >
> >Another issue:  What temposonic do you want in the actuator.
> >Digital--or analog?  When I did my count of transducer modules, I
> >assumed we would have a module for the tempo, but I did not know if
> this
> >is really needed.  What is really needed????   If digital, do we need
> >any 497 module?
> >Tom K.
> >
