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No. |
Description |
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332 |
Reversing Switch (With Lock type
terminals) |
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333 |
Plug-Type (One way), Brass (9/16"
Square rod) |
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334 |
Plug Type (Two way), Brass (9/16"
Square rod) |
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335 |
Tapping key (Single contact) |
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336 |
Tapping key (Double contact) |
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1.0 Kelvin Double Bridge (Model No.
KDB-2021)
Range 0.2 ohm to 11 ohm
It is used as standard testing instrument used for accurate measurement
of very low resistances such as shunts, copper & aluminum
conductors/wire and specific resistance determinations of heavy
distribution transformers. The bridge comprise 10 steps of standard
resistance of X 0.01 ohms and a circular slide wire having total
resistance of 0.01 ohm & divided into 500 equal parts so that each
division correspond to 0.00002 ohm (or 20 micro-ohm). It is also
provided with 5 multiplier ranges of X 0.001, X 0.1, X 1, X 10 & 100 so
that the overall range becomes 0.2 Micro-ohm to 11 ohms. Provided with
built in compensation arrangement for taking into consideration self
resistance of leads from bridge to test object. Complete with one
standardized set of 8 leads for interconnections. All standard
resistance coils used inside are of Aged Manganin wire/strip so that
overall accuracy of 0.05 % is achieved. This model is mostly used in
wire & cable industries & conforms to IS : 694 & 1554 & hence it is also
named as Industrial Kelvin Double Bridge. |
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Accessories
a) DC source of 10 Amps (Model DC-341)
b) Spot Reflecting Galvanometer (Model RG-321)
c) Conductivity attachment of 50 cm length for holding sample (Model No.
CA - 361)
d) Brass Clamp with very thick terminals at both side & one at centre
for testing zero of kelvin bridge (Model No.BC-381)
e) Standard Resistance box having five values of 0.001, 0.01, 0.1, 1, 10
ohms enclosed in one box, used as Standard for checking Kelvin Bridge
(Model No. SR-391), Accuracy 0.5 %. |
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Other Models :
1. Senior Kelvin Double Bridge ( Model No. KDB-2041)
( Range 0.02 micro-ohm to 1.1 ohm)
2. Precision Kelvin Double Bridge (Model No. KDB-2061),
Range 2 micro ohm to 110 ohm)
3. Wide Range Kelvin Double Bridge ( Model KDB-2081 )
Range 20 micro-ohm to 1100 ohm) |
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Callendar and Griffth Bridge
Suitable for measurement of change of resistance thermometer, Coil are
of Manganin. The bridge wire is accurately calibrated, A vernier is
attached fine slow motion is available. Special mercury contacts,Length
of slide wire 30 cms. Resistance Values are 0.1, 0.2, 0.4, 0.8, 1.6,
3.2, 6.4, 12.8 ohms and 0.15 ohms for slide wire. Measurable resistance
0.0005 to 25.65 ohms. Accuracy of adjustment 0.01 % ( Also known as
Platinum Resistance Thermometer Bridge) |
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Rayleigh’s Bridge
For measurement of self inductance of a coil.
a) Ratio arms in 3 dials of 1, 10, 100 ohms each.
b) Three Rheostat dials having fractions units and tens.
c) Slide wire having 0.15 ohms is connected in series with Rheostat arm.
The slide wire is calibrated in 100 equal parts.
d) Rayleigh’s special key is fitted on panel.
e) Terminals for extra series and unknown inductance provided. |
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DC Potentiometer
It has got eight steps of 2 ohms and a slide wire of equal resistance.
The circular slide wire is divided into 200 parts and is calibrated to
read in millivolts. All these in series with coarse and fine rheostat
provide the standardising unit. Terminals are provided for a 2-3 volts
battery, standard cell, galvo and two sets of external test circuits
worked by a rotary switch. A self check is provided by a fixed tap in
the circuit corresponding to the standard cell e.m.f. of 1.0186 volts.
Range 0.0005 to 1.8 volts Manganin Coils. Accuracy 0.05%.
a) Volt Ratio Box
For extension of range of potentiometer. Range 1.5, 15, 150.300 & 750
volts.
Total Resistance 37500 ohms (dial type).
b) (i) Standard Cell (Cadmium) Voltage = 1.0186 V
(ii) Standard Cell (Electronic)
c) 2 V Accumulator (Constant Voltage Source) |
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