Albert Nestler, Lahr in Baden / Germany                 (1940)
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                                                   VERSION (B)

S C A L E S  of  the   NESTLER   » E L E K T R O «    Model 37
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Front Side                                           Back Side
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( 0 .. 25 cm Ruler )

     V       X * 1.75
(A)  PS      X2
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(B)  KW      X2                           S         sin(0.1X)
     ( 30 .. 54 cm RULER IN BASE )        S&T       arc(0.01X)
(C)          X                            T         tan(0.1X)
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(D)          X
     U       X * 5.24
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(LL2)        exp(0.1X) = keyed to SCALE A and LEFT CURSOR-MARK
(K)          X3

R E M A R K S :                     (  1° = 60' ;   1' = 60" )
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The  TRIGONOMETRIC SCALES  are  divided  in  MINUTES & SECONDS

The no-named scales are marked here with their common symbols
in brackets: (A),(B),(C),(D),(LL2),(K).

The U-Scale is folded by ( for calculating "Revol./Minute" )
    π / 60  =  0.05236
The V-Scale is folded by the "Specific Resistance of Copper"
    sRcu  =  0.0175 Ω * mm2 / m
The CU-Marks  for  "Specific Conductivity of Copper"
    sCcu  =  57.2 m / Ω * mm2  =  1 / sRcu
The 736-Mark  for
    1 PS  =  0.7355 kW  with "Effectiveness"-Marks for
    MOT (=Motor) & DYN (= Dynamo)
The Mark  sqrt(2g) = 4.429  for  "Pressure Hight" calculations

There are 3 Versions of "Model 37" in this collection:

In this VERSION (B) the CURSOR IS FRAMELESS AND
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the cursor's hairlines are different and NOT SYMMETRICAL:

The CENTRAL (black) and the RIGHT (red) are in the common
distance (on A-Scale) AREA/DIAMETER (on X-Scale) - but the
LEFT (red) is SHIFTED to the left (= 736-Mark Distance).

Because the cursor's side-window was missing, it had to be
  h o m e - m a d e  with  this  C A L I B R A T I O N :
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Set the cursor's central hairline at "2" on X-Scale, the
right hairline on the SIDE-WINDOW (green) has to read "8"
on K-Scale. Set cursor's left hairline at "10" on A-Scale
(the central hairline now at DYN on A-Scale),  the left
hairline on the SIDE-WINDOW (red) has to read "e" on LL2.

There is ANOTHER VERSION ( X ) on earth !!!
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The NESTLER BOOKLET "Electro No.37" (i.German), is showing
a "Model 37" with a DIFFERENT CURSOR & DIFFERENT SCALES ...

 

In VERSION (A):
The  CURSOR HAIRLINES  are symmetrical and in the common
distance (on A-Scale) AREA/DIAMETER (on X-Scale).
The LL2-Scale is  UNDER  the CUBIC-Scale and SHIFTED so,
that CUBIC "45" is over LL2 "e"  =  ONLY 1 SIDE-HAIRLINE.

In VERSION (C):
The SR is longer, has a red  1/X  and  "extended"  Scales.
The  CURSOR HAIRLINES  are symmetrical again and in the
common distance (on A-Scale) AREA/DIAMETER (on X-Scale).
The LL2-Scale is placed  OVER  the CUBIC-Scale and SHIFTED,
that CUBIC "52" is under LL2 "e".  2 CURSOR SIDE-Hairlines.

Historical Remarks ...

The slide rule came in a black cardboard case. It is made of
mahogany with scales on celluloid veneer.  The back side's
table with constants was missing - and also the cursor's
side-window was missing and had to be home-made (s.above).

impressum:
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© C.HAMANN     http://public.BHT-Berlin.de/hamann      10/11/21