PSN-L Email List Message

Subject: Re: Damping CDR for HS10-1
From: Geoffrey gmvoeth@...........
Date: Fri, 24 Jun 2011 19:46:58 -0700


Hello Mr. O'Donnell;

It seems to me that I have been
putting the decimal point
one place to the right too far.

According to this info plugged into the
equation
Hm=0.031
H=1/sqr(2)
He=H-Hm
G=2.99V/(in/sec)
M=33oz
During Summer When Hot Rg=440 Ohms
Rt = G^2/ (2mW0He)
I get the following results
Rt = (100*2.99/2.54)^2/(2*0.935534*2*Pi*(1/sqr(2)-0.031))
Rt=1743 ohms
so this should mean the damping resistor
would be Rt-Rg=Rd = 1743-440=1303 OHMS
Since I cut this Rd in half to fit into my circuit
I need two resistors with my instrumentation amp
of 1303/2 or 652 ohms (cant really see 1/2 ohms)

This should give me butterworth like rolloff for damping.

If the mechanical damping were like Hm=0.31
Id need a RT of 3300 ohms instead of 1743 ohms

So I have been using totally wrong numbers till now
to plug into this equation.

I have already made the damping change
just will waiut to see what the new picture looks like.

Thanks for pointing me to the site.

Thanks PSN for pointing me to the formulas.


Regards,
geoff
----- Original Message ----- 
From: "Jim ODonnell" 
To: 
Sent: Friday, June 24, 2011 6:15 PM
Subject: Re: Damping CDR for HS10-1


Geoffery-
I have an old HS10-1 Hz, Z (~400 ohms) and recently compared it with a new 1 Hz China phone (3.5kohm).  At the low end 0.1 to 5 Hz 
it had a smaller output...
The China phone is not damped but becomes damped with the seismograph I use.
It did lose some gain when used with LC's system.

Geo Space geophones:
http://www.korins.com/m/gs/hs10.htm
 The HS-10 is a high-sensitivity, self-generating 
velocity detector with extremely low natural frequencies. It has been used for nearly three decades to detect seismic activity in 
applications such as seismology, structural analysis, etc.

HS-10-1
Functional
Sensitivity (  10%)
2.99 V/ips
4.66 V/ips
9.80 V/ips
29.8 V/ips
62.8 V/ips
Natural Frequency (  10%)
1 Hz
1 Hz
1 Hz
1 Hz
1 Hz
Coil Resistance (  10%)
400 ohms
970 ohms
4100 ohms
50,000 ohms
210,000 ohms
Coil Inductance
360 mh
870 mh
3500 mh
35 h
150 h
Damping Factor (  20%)
..031
..031
..031
..035
..035
Damping Constant
1178
2862
12656
133255
591794
Displacement Limit
0.5 in
0.5 in
0.5 in
0.5 in
0.5 in
Inertial Mass
33 oz
33 oz
33 oz
29.0 oz
29.0 oz
Orientation Angle
 5
 5
 5
 5
 5
Mechanical
Height
5.40 in
5.40 in
5.40 in
5.40 in
5.40 in
Diameter
4.38 in
4.38 in
4.38 in
4.38 in
4.38 in
Weight
9.75 lbs
9.75 lbs
9.75 lbs
9.50 lbs
9.50 lbs



Jim O'Donnell BC-Geophysics
Geophysical Consultant/Contractor
Geotechnical/Geothermal/Oil & Gas/Mining Applications
Seismic Surveys- Surface Waves, Refraction, & Reflection
Ground Penetrating Radar, Resistivity, Magnetic, & VLF-EM Surveys
Geophysics@..........  702.293.5664  702.281.9081 cell
Boulder City, NV


---------- Original Message ----------
From: Geoffrey 
To: "PSN_LIST" 
Subject: Damping CDR for HS10-1
Date: Fri, 24 Jun 2011 16:12:12 -0700

Hello PSN,

I have never found the exact specs for the HS10-1
which i now have.

In regards to damping;
Which sounds more realistic,
h(mechanical) = 0.35
or
hm = 0.035

??


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