Atec Megger-TTR300 Series - Manual (Page 4)

Turns Ratio Range and Accuracy
8 V ac: ±0.1% (0.8 to 2000)
±0.25% (2001 to 4000)
±0.35% (4001 to 8000)
40 V ac: ±0.1% (0.8 to 2000)
±0.15% (2001 to 4000)
±0.3% (4001 to 10,000)
±0.35% (10,001 to 25,000)
80 V ac: ±0.1% (0.8 to 2000)
±0.15% (2001 to 4000)
±0.25% (4001 to 10,000)
±0.30% (10,001 to 45,000)
Resolution: 5 digit for all ratios
Printer Interface
TTR300: Not applicable
TTR310: RS-232 port
TTR320: RS-232 port
TTR330: USB
Computer Interface
TTR300 and TTR310: RS-232 port
TTR320 and TTR330: Ethernet
User Interface
TTR300: Not applicable
TTR310: 5.7 in., B&W display, text on-screen view,
numeric keypad
TTR320: 5.7 in., full-color VGA, graphical icon on-screen view,
full QWERTY keypad and navigational pushbuttons
TTR330: 8.4 in., full-color VGA, test forms on-screen view,
full QWERTY keypad and navigational pushbuttons
Internal Data Storage
TTR310: up to 200 data sets
TTR320 and TTR330: up to 100,000 data sets
Communication/Control Software
PowerDB LITE and PowerDB (full version, optional)
TTR330: PowerDB ONBOARD
Transformer Winding Phase Relationship
ANSI C57.12.70-1978
CEI/IEC 76-1:1993 and Publication 616:1978
AS-2374, Part 4-1982 (Australian Standard)
Safety/EMC/Vibration
Meets the requirements of IEC-1010-1, CE and ASTM D999.75
Temperature Range
Operating: 23° F to 122° F (-5° C to 50° C)
Storage: -58° F to 140° F (-50° C to 60° C)
Relative Humidity
0 to 90% noncondensing
Measuring Time
8 to 20 seconds depending on mode of operation and
type of transformer
Measurement Method
ANSI/IEEE C57.12.90
Dimensions
8.5 H x 21.5 W x 13 D in.
(216 H x 546.1 W x 330.2 D mm)
Weight
Instrument only, not including leads
TTR300: 20 lbs (9.1 kg)
TTR310: 23 lbs (10.4 kg)
TTR320: 25 lbs (11.3 kg)
TTR330: 25 lbs (11.3 kg)
TTR ® 300 Series
Three-Phase Transformer Turns Ratio Test Sets
APPLICATIONS
The TTR300 Series applies voltage to the high-voltage
winding of a transformer and accurately measures the
resulting voltage from the low voltage winding. In addition
to turns ratio, the units measure excitation current, phase
angle deviation between the high- and low-voltage
windings and percent ratio error.
Transformer Turns Ratio
Transformer turns ratio is the ratio of the number of
turns in the high-voltage winding to that in the low-
voltage winding. Complexity in the measured ratio versus
nameplate ratio occurs with most three-phase power
transformers because multipliers such as √3 are required
to match the measured ratio to the nameplate ratio. The
TTR300 Series automatically applies the multiplier in a
form which allows the operator a direct comparison to
the nameplate (or expected) ratio. The built-in calculator
displays the % error versus nameplate for each tap and
each winding, without the need for a computer.
Exciting Current
The TTR provides accurate measurement of exciting current
(to 0.1 mA) which can help provide information about the
condition of a transformer’s core. Unwanted circulating
currents or unintentional core grounds can increase the
exciting current and indicate a problem.
Phase Angle Deviation and its Application
The phase angle deviation, displayed in either degrees
(minutes) or radians, is the phase relationship between the
voltage signal applied to the high-voltage winding and the
voltage signal extracted from the low-voltage winding. The
phase deviation, together with ratio error, can be used as a
low-cost method of verifying accuracy class of all types of
PTs and CTs at “zero burden.”
The phase deviation between the high and low side of a
transformer is generally very small. If there is deterioration
or damage in the transformer core, however, the phase
deviation can change significantly. The three-phase TTR
can measure this phase relationship with the resolution
of 0.1 minutes (equal to 1/600 of a degree), which is
necessary to detect problems.
SPECIFICATIONS
Input Power
120/230 V ac ±10%, single phase, 50/60 ±2 Hz 100 VA
Battery Operation (Optional)
Inverter 12 V dc to 120 V/230 V ac for operation from vehicle bat-
tery
Excitation Voltage
8, 40, or 80 V rms, automatically or manually selected
Excitation Current Range and Accuracy
0 to 500 mA, 3 digit resolution, ±(2% of reading + 1 digit)
Phase Deviation Range and Accuracy
±90 degrees, 1 decimal point for the minutes display, 2 decimal
points for the degree display, or for the centi-radian display
Accuracy: ±3 minutes