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Precision Instruments
This high current, digital, direct reading,
microprocessor based transformer ohmmeter will
measure the D.C. resistance of power transformers
and other electrical devices where high
inductance is also present. With a choice of
single or dual measuring channels (models
5896 or 5896b). With a fast initial settling time
this ohmmeter provides the best overall
solution to DC resistance testing of
transformers. Notoriously difficult transformer
types including 3 phase closed delta and autotape changers. Small pole mounted to large
distribution types with 3 or 5 limb construction
are easily measured using the 5896. With 6
ranges from 2 millohms to 190 ohms, a choice of
2 current per range, and a basic accuracy of 0.1%.
The single or dual channel measurement of primary
or primary and secondary transformer winding
resistance is displayed on a large LCD screen to 4
1/2 digit resolution.
An advanced, high power, wide ranging ohmmeter
for fast accurate measurements of transformers or
Features
other inductive loads. With built-in data storage and
One or two independent measuring channels
interfacing to PC or external printer. Suitable for a
High current (25A)
wide range of factory, on-site plant measurement
High accuracy (0.1%)
and performance testing applications including:
High resolution to 0.1µohm
• Transformer dc winding resistance
41⁄2 digit large display to 19000
• Generator stator/rotor resistance
Wide range 1 milliohm to 190 ohms
• Large motors
Rapid saturation to read time on Y-∆ transformers
(>30 secs)
• Power utility sub-stations
• Transformer tap-changer operation and
contact tests
• Routine plant maintenance and “Benchmarking”
•
Storage of data on internal memory
Built-in printer for time and readings records.
Constant current regulated supply eliminates Ldi⁄dt effects
for fault finding
6 ranges, choice of two currents/range
Factory testing to international standards.
Large LCD screen for data presentation
• Transformer “Heat-run” tests
RS232/IEEE488 computer interface
• Power connections and circuit breaker testing
Over temperature protection
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Precision Instruments
Technical Data
Features and Benefits
The 5896 is microprocessor
The use of special current control
based with menu driven options
circuits enables large transformers
selected via front panel controls.
particularly closed delta types to
With electronic calibration, the
be quickly saturated enabling the
instrument can be easily
initial first reading to be made
recalibrated against known
within 60 seconds for most
external standards. User
transformers. This is important
controlled internal software
when making “heat-run” tests to
allows data logging and storage
comply with various international
of measurements in the
standards. In addition the special
instruments internal memory.
circuits employed limit the Ldi
The RS2323/IEEE488 interface
effects that can give rise to noise
enables stored data to be down
and unstable readings.
loaded to a computer or external
printer. The instrument may also be
fully controlled via the interface.
When testing tap-changers
where accurate measurement of
contact resistance of the taps is
important the high resolution of
the 5896, to 1 part in 19000,
provides an accurate means to
detect potential problems.
Model 5896
Specification
Range
Nominal Value
Full Range Display
Current
High - Low
Resolution
Accuracy
1
2
1mΩ
1.9000mΩ
25A-10A
0.1µΩ
±0.1%
10mΩ
19.999mΩ
25A-10A
1.0µΩ
±0.1%
3
100mΩ
190.00mΩ
10A-5A
10µΩ
±0.1%
4
1Ω
1.9000Ω
5A-1A
0.1mΩ
±0.1%
5
10Ω
19.000Ω
1A-0.25A
1.0mΩ
±0.1%
6
100Ω
190.00Ω
0.25A-0.1A
10mΩ
±0.1%
Measuring time
Environment:
Initial first reading (saturation time of transformers)
• 0 TO 45°C at 50/RH non condensing
Typically 4 to 60 seconds
• Dimensions 470x204x350mm
Normal reading rate 2 seconds
• Nett weight 32kg
Accessories:
Inputs:
• Calibration certificate traceable to National Standards - included
Measuring: 2 current and 2 voltage/channels (isolated)
• Soft padded. heavy duty case for on-site protection - included
Mains: 100/120/220/240V 50 to 60 Hz
• Connection cable sets - extra
Outputs: RS232C IEEE488 option
Number of inputs
Printer: built-in paper strip
Model 5896 1 Channel
Ordering information and accessories
Model 5896B 2 Channels
5896
Single Channel with RS232
5896B
2 Channel for two winding measurement with RS232
5896/IE
Single Channel R5232 and IEEE488
5896B/IE
2 channel with R52322 and IEEE488
5896IE
IEE488 Option (retrofit)
5896-2CH
Second channel option for (5896 retrofit)
5896/Cl
4 metre 4 wire 25A Cable Set
5896/C2
12 metre 4 wire 25A Cable Set
5896/C3
20 metre 4 wire 25A Cable Set
5896/PP
Printer Paper (10 rolls)
Display
LCD Screen 70x127mm displaying: selected current, time,
date, range and resistance value for 2 channels
Overall range: 0.lµΩ to190Ω in 6 ranges
Overall accuracy: ±0.l% of reading ± I digit
Resolution: 0.1µΩ to 10mΩ over 6 ranges
(0.005% / I part in 20 000)
Test currents: 0.IA to 25A max
5896/4737B Calibration unit
275 King Henry’s Drive, New Addington, Croydon, CR0 0AE, England
Telephone 44 (0) 1689 800799 Fax 44 (0) 1689 800405
0057