Atec Vanguard_WRM-40 - Manual (Page 2)

WRM-40
winding resistance meter
The WRM-40 is designed to accurately measure the winding resistance of
highly inductive power transformers. The unit’s dual resistance-reading input
channels can measure two winding resistances simultaneously, and four-wire
(Kelvin) connections provide high accuracy and require no lead compensation.
The WRM-40 provides stable resistance readings of very large transformers
by utilizing a 36Vdc power supply capable of outputting up to 40 Amperes.
The resistance reading of a 500MVA transformer can be achieved in 5 minutes
or less. The unit’s power supply is cooled by four heavy-duty fans designed for
continuous operation. For greater fl exibility in the fi eld, the WRM-40 comes
with a built-in 2.5-inch wide thermal printer used for printing test reports.
2
Internal Test Record
Storage
The WRM-40 can store 63 test records (up to
48 readings per test record) in Flash EEPROM.
Test records can be retrieved and printed on the
built-in thermal printer or can be transferred to a
PC via the RS-232C interface port. A Windows®
-based application is provided with each WRM-
40 that can be used to retrieve test records from
the WRM-40 and can also be used to export re-
cords in Microsoft® Excel format.
User Interface
The WRM-40 features a back-lit LCD screen (20
characters by 4 lines) that is viewable in both
bright sunlight and low-light levels. A rugged,
alpha-numeric, membrane keypad is used to
control the unit.
outstanding features
• Auto discharge circuit for operator safety
• Auto current ranging from 10 mA to 40 A
• Digital resistance reading from 1 micro-
ohm to 500 ohms
• Stores 63 records (of 48 readings each)
• Built-in 2.5-inch wide thermal printer
Since the WRM-40 can accurately measure re-
sistances ranging from 1 microohm to 500 ohms,
it can also be used to measure EHV circuit-
breaker contact resistance, motor winding resis-
tance, or any low resistance. If the transformer
winding temperature is entered, the WRM-40
can calculate the equivalent resistance value of
the winding material (aluminum or copper) at
any standard reference temperature. Also, a spe-
cial test mode can run a test for up to 45 minutes
while saving resistance readings at one-minute
intervals. In addition to measuring the resistance
value, the WRM-40 also checks the “make-be-
fore-break” tap switching sequences of voltage
regulators and load tap changers.
The WRM-40 can store test results in Flash EE-
PROM. Test results can be printed on the built-in
2.5-inch wide thermal printer or can be trans-
ferred to a PC via the RS-232C interface port.
The WRM-40 is furnished with three 50-foot
test cables. Each test cable lead is terminated
with a quick-disconnect test clip.
Built-in Safety Features
At the end of each test, the WRM-40 automati-
cally dissipates the stored energy in the trans-
former. This discharge circuit will continue to
work even if the supply voltage is lost. For added
safety, the unit’s power supply is thermally pro-
tected from over-load damage.
Built-in Thermal Printer
The WRM-40 features a built-in 2.5" wide ther-
mal printer that can be used to print test reports
in the fi eld.