PSN-L Email List Message
Subject: Re: Another New Lehman
From: ChrisAtUpw@.......
Date: Fri, 9 May 2008 00:16:06 EDT
In a message dated 2008/05/09, tchannel1@............ writes:
> It has a proven hinge, top and bottom. Proven in that I have used this
> approach before several times and it was successful. ball bearing for the
> bottom and wire for the top.
Hi Ted,
What have you used for the hard counterface for the ball bearing? I
use either a polished tungaten carbide triangular tool tip or a SS scalpel
blade, stuck in place with acrylic glue.
> The period is set at 20 seconds, and this was difficult, but I got it.
This should not be difficult.
> The coil is 3600 turn and magnets are also proven design.
> The boom is pointing East West.
> The damping is as expected.
> I did get this earthquake on two other sensors one vertical and one tilt
> meter (just a 48" pendulum) swinging East West.
>
> Q. Could it be over damped?
> Q. With the period at 20 second, could this be too high? Too high for this
> earthquake?
> Q. Could it be the base on which the sensor is position? It is carpet, on
> top of the carpet are concrete blocks, SS pads, and the sensor set on these.
> I have used this on many other short period sensor, and it works for those.
>
> I see nothing wrong. It does record all the road construction, and my
> movements around the room.
You can easily check the damping. Push the boom 10 mm to one side with
a pencil or similar and release it. It should swing about 1/2 mm past the
zero position. I use a magnifying glass and a transparent ruler to observe this.
You should have seen the Love waves.
Regards,
Chris Chapman
In a me=
ssage dated 2008/05/09, tchannel1@............ writes:
It has a proven hinge, top and=20=
bottom. Proven in that I have used this approach before several=20=
times and it was successful. ball bearing for the bottom and wire for=20=
the top.
Hi Ted,
What have you used for the hard counter=
face for the ball bearing? I use either a polished tungaten carbide triangul=
ar tool tip or a SS scalpel blade, stuck in place with acrylic glue.<=
FONT COLOR=3D"#000000" BACK=3D"#ffffff" style=3D"BACKGROUND-COLOR: #ffffff"=
SIZE=3D3 PTSIZE=3D12 FAMILY=3D"SANSSERIF" FACE=3D"Arial" LANG=3D"0">
The period is set at 20 second=
s, and this was difficult, but I got it.
This should not be difficult.
The coil is 3600 turn and magn=
ets are also proven design.
The boom is pointing East West.
The damping is as expected.
I did get this earthquake on two other sensors one vertical and one tilt me=
ter (just a 48" pendulum) swinging East West.
Q. Could it be over damped?
Q. With the period at 20 second, could this be too high? Too high for=
this earthquake?
Q. Could it be the base on which the sensor is position? It is=20=
carpet, on top of the carpet are concrete blocks, SS pads, and the sensor se=
t on these. I have used this on many other short period sensor,=20=
and it works for those.
I see nothing wrong. It does record all the road construction,=20=
and my movements around the room.
You can easily check the damping. Push=20=
the boom 10 mm to one side with a pencil or similar and release it. It shoul=
d swing about 1/2 mm past the zero position. I use a magnifying glass and a=20=
transparent ruler to observe this.
You should have seen the Love waves.
Regards,
Chris Chapman
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