PSN-L Email List Message

Subject: Re: What Do you think
From: "Bryan & Regina Goss" bgoss@..................
Date: Mon, 22 Jan 2001 22:00:26 -0600

 I was able to get about 17 seconds and it took about 2 hours, I almost
settled for less. It seems to work great except the shop floor tilts a lot
with temperature changes I must adjust every 3 to 5 days this is bothersome.
Thank you for your suggestions I will use them I plan to build another one
or two.
----- Original Message -----
Sent: Monday, January 22, 2001 9:36 PM
Subject: Re: What Do you think

> In a message dated 22/01/01, bgoss@.................. writes:
> > Well I finally got my sight updated tell me what you all think.
>     The results look OK, which is what counts.
>     I see that you have used both magnetic and fluid damping. With the
> magnetic damping, you have used Al plate which is not nearly as effective
> Cu and you have also used a very large magnetic gap. This suggests that
> magnetic damping is a sort of 'add on' correction. The problem with fluid
> damping in general is the huge changes in fluid viscosity with
> particularly between summer and winter. If it works OK, don't 'fix' it. If
> you want to experiment at any time, I suggest you try a bit of 1/8" Copper
> plate, no fluid and reduce the magnet gap till you get ~critical damping.
> This will be independent of temperature.
>     You might want at some stage to fit a small underrun lamp (1/2 to 2/3
> rated voltage) inside the top of the box to give a stable temperature
> gradient to the internal air. A layer or two of bubble wrap with suitable
> viewing holes cut in it could provide additional insulation while still
> allowing light through. A layer of polythene damp proof sheeting under the
> whole apparatus could prevent any condensation problems from the flooring.
> you get any problems with lightning where you are, you might consider
> mounting the amplifier on the baseplate and connecting the baseplates
> together with a common earth.
>     For others still in the design stage, you can get threaded Brass and
> Stainless Steel rods, which are both non magnetic and so won't give
> with magnetic interactions. Another alternative is to get plain rod and
> some thread put one end. Mounting the sensor system just inboard of the
> weight can give a more compact system. Socket cap screws can make
> adjustments easier to perform and fine threads are available - it is a bit
> easier to get an extension rod into a hole than a flat screwdriver bit
into a
> slot.
>     What stable period did you manage to get?
>     Good for you and Good Luck!
>     Chris
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Larry Cochrane <cochrane@..............>