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AUTOMATIC TRANSFORMER RATIOMETER TRANSFORMER TESTER

4167D Automatic Transformer Ratiometer. Transformer Tester.
This mains operated, automatic Digital Transformer Ratiometer, measures the transformation ratio (primary to secondary turns ratio) and can also give an indication of any small phase difference between the high voltage and low voltage windings of transformers. 

Automatic Transformer Ratiometer

• Direct Ratio Reading from 1:1 to 9990:1

•  High accuracy to 0.1%

• Resolution to 1 part in 10,000 

• Display of phase difference indication and H.V. winding voltage 

• PC interfaces (RS232; IEEE488; RS385; RS422) 

• Bright red LED displays 

The Ratiometer transformer tester can be used in factory production test areas or other locations where a suitable supply voltage exists. The model 4167D operates accurately to turns ratios of 1000:1 for power transformers. While the extended range model 4167DH operates to 9990:1, for both power transformers and many types of current transformer. 

The models 4167D and 4167DH transformer ratiometer, cover a wide automated reading range
from 1:1 to 9990:1, are supplied fully calibrated and offer a basic accuracy of 0.1%.
Each transformer tester features both parallel and serial interfaces enabling their use as part of a wide range of automated control and data logging systems. 

Transformer Ratiometer Applications include: 

• Power transformer ratios 

• Potential transformers

• Current transformers

• Power utility sub-stations 

• Routine plant maintenance and “Benchmarking” for fault finding 

• Factory testing to international standards 

• Tap changer transformer defects

In use the transformer is connected with the high voltage winding wired to the H.V. terminals of the instrument and the low voltage winding connected to the L.V. terminals. The transformer high voltage winding is then energized at normal line voltage (90 to 260V, 40 to 70Hz) even if the transformer under test has a much higher voltage rating. The ratio reading is indicated on a large 7 segment LED display and is fully automatic with no range changing or tedious balancing required. 

Transformer Ratiometer Technical Data 

The model 4167D and 4167DH Transformer Ratiometers measure transformer voltage ratio, give an indication of any phase difference, or applied energizing voltage on power transformers and some current transformers. 

Incorporating two large bright LED displays. One display automatically provides the ratio value and the second can be selected to indicate phase difference or the energizing voltage being supplied to the H.V. side of the transformer. 

In normal use, the high voltage winding of the transformer is energized by the user at AC. line voltage and connected to the Ratiometer H.V. terminals. The low voltage winding (step down) is connected to the L.V. terminals of the Ratiometer. The display of ratio and phase is then entirely automatic with no switching or other manual operation required by the user. 

The model 4167D is suitable for transformer ratios to 1000:1 while the 4167DH, extended range version, provides accurate ratio to 9990:1 to cover voltage and current transformers. 
The automatic range changing facility enables the display to give the highest resolution for the ratio being measured e.g. ratios 1 to 100 show 10.00 to 99.99 etc.

Measurement system 

The measurement technique used is to measure the H.V. and L.V. winding voltages during several parts of the applied AC voltage cycle to obtain in-phase and quadrature values. From these values the ratio and phase difference are calculated. The inputs to the Ratiometer are isolated by transformers, fuses and surge absorbers, therefore the instrument should not be damaged by the very high voltages possible if the connections from the transformer being measured are accidentally reversed. 

Computer interfacing 

A very flexible computer interface system is fitted allowing IEEE488, and serial RS232, RS422 and RS485 communication with the instruments. 

When using another measuring instrument with a IEEE4S8 output the 4167D/ DH can operate as a controller. This converts the IEEE488 input from the second instrument to serial format enabling its control via the 4167D/DH serial interface. 

Automatic Transformer Ratiometer Specifications
Range	1:1 to 9.999:1	10:1 to 99.99:1	100:1 to 300:1	100:1 to 999.9	1000:1 to 9990
Accuracy 4167D	0.1%	0.1%	0.1%	0.25%	-
Accuracy 4167DH	0.1%	0.1%	0.1%	0.1%	0.1%
Resolution 4167D & DH	0.001	0.01	0.1	0.1	1.0

Overall range 

4167D 1:1 to 1000:1 
4167DH 1:1 to 9990:11 

Overall accuracy 

4167D  0.l TO 0.25% 
4167DH 0.1%