DV Power Winding Ohmmeter RMO10TW User Manual Brochure

User Manual: DV-Power-Winding-Ohmmeter-RMO10TW-User-Manual-Brochure

Open the PDF directly: View PDF .
Page Count: 6

B-RXX0TW-305-EN, 2017-08-16

1

Winding Ohmmeter RMO-TW

Description

The Winding Ohmmeter of the RMO-TW series is

designed for winding resistance measurement of

inductive objects. The RMO-TW instrument is

based on the state of the art technology, using

the most advanced switch mode technology

available today. The RMO-TW instrument is

accurate (0,1%), powerful (up to 50 A) and

lightweight. It generates a true DC ripple free

current with automatically regulated

measurement and discharging circuit.

RMO-TW instrument can perform a simple, quick

and reliable transformer on-load tap changer

verification. This instrument enables

measurements of a winding resistance in every

tap position of an on-load tap changer without

discharging between the tests. Problems with

switching of the OLTC, such as interruption, can

be detected with these measurements. The

results are displayed on a backlit LCD display.

Application

The list of the instrument application includes:

 Three-channel winding resistance measurement, which enables simultaneous winding resistance

measurement of up to three windings on a single phase

 Detection of interruptions during the operation of on-load tap changers (OLTC), performed on a single

phase

 Heat Run test, which enables obtaining the Hot Spot temperature along with resistance graph during

the cooling process

 Three resistance measurement channels

 One temperature measurement channel

 Accuracy 0,1 %

 Lightweight

 On-load tap changer verification

 Automatic resistance measurement for the Heat Run test

 Rapid automatic demagnetization

 Automatic discharge circuit

 Resistance measurement of transformers, rotary machines and non-inductive objects

 Four models: RMO10TW, RMO20TW, RMO30TW, RMO50TW

B-RXX0TW-305-EN, 2017-08-16

2

Connecting RMO-TW to Transformer

The RMO-TW has three separate resistance

measurement channels, which enable

simultaneous measurement of the primary,

secondary and tertiary winding on the same

phase, as presented in the figure above. This

significantly speeds up the measurement and

reduces the total transformer testing time. At the

same time, by saturating the magnetic core

through the HV and LV windings the stabilization

time and subsequently the total testing time is

reduced even more.

Simultaneous Three-Channel Winding

Resistance Measurement

The RMO-TW injects the current with a voltage

value as high as 55 V. This ensures that the

magnetic core is saturated quickly and duration

of the test is as short as possible. The three

independent channels enable simultaneous

testing of three windings in series – primary,

secondary and tertiary windings. There is enough

memory within the RMO-TW instrument to store

1 000 measurements. All measurements are time

and date stamped.

The instrument is equipped with thermal and

overcurrent protection. The RMO-TW has very

high ability to cancel electrostatic and

electromagnetic interference that exists in HV

electric fields. It is achieved by a proprietary

filtration solution applied to both, the hardware

construction and the application software

implementation. A special mode is provided for

the resistance measurement in multiple de-

energized tap changer (DETC) positions.

Resistance Testing in Multiple Tap

Changer Positions

The winding resistance of all tap changer

positions in one phase can be measured as part

of a single test, without discharging between

measurements. Different test modes are

provided for on-load tap changers (OLTC) and

de-energized tap changers (DETC). The

instrument detects interruptions during the

operation of on-load tap changers and produces

a warning message to the operator.

Automatic_Transformer

Demagnetization

After a DC current test, such as a winding re-

sistance measurement, the magnetic core of a

power or a measurement transformer may be

magnetized. Also, when disconnecting a

transformer from a service, some amount of

magnetic flux trapped in the core could be

present.

The remnant magnetism can cause various

problems such as erroneous measurements on a

transformer, or an inrush current at start-up of a

power transformer, or an incorrect operation of

the protective relays due to the magnetized CT

cores. To eliminate this source of potential

problems, demagnetization should be performed.

When the discharging process has been

completed, the RMO-TW can perform fully

automatic demagnetization.

Demagnetizing the magnetic core of a

transformer requires alternating current applied

with decreasing magnitude down to zero. The

RMO-TW provides this alternating current by

internally changing the polarity of a controlled DC

current.

B-RXX0TW-305-EN, 2017-08-16

3

DV-Win Software

The DV-Win application software enables

control and observation of the test process, as

well as saving and analyzing the results on a PC.

It provides a test report, arranged in a selectable

form as an Excel spreadsheet, PDF, Word, or

ASCII format. The software provides additional

OLTC (tap changer) verification option by

recording the test current during the transition.

The standard interface is USB. RS232 is

optional.

Heat Run Test Application

The DV-Win application software has an

additional Heat Run temperature/resistance

extrapolation feature. After the transformer

heating is switched off, the RMO-TW is

immediately connected to up to three transformer

windings and the timer is started. The winding

resistance is measured at regular time intervals.

This information is used to automatically

extrapolate the values of temperature and

resistance at the moment when the transformer

was switched off.

B-RXX0TW-305-EN, 2017-08-16

4

Technical Data

Winding Resistance Measurement

 Test currents:

̶ 5 mA – 10 A DC for RMO10TW

̶ 5 mA – 20 A DC for RMO20TW

̶ 5 mA – 30 A DC for RMO30TW

̶ 5 mA – 50 A DC for RMO50TW

 Output voltage: up to 55 V DC

 Measurement range: 0,1 μΩ - 10 kΩ

 Typical accuracy:

±(0,1% rdg + 0,1% F.S.) for 0,1 μΩ-1,999 kΩ range

±(0,2% rdg + 0,1% F.S.) for 2 kΩ - 10 kΩ range

Resolution

 0,1 μΩ – 999,9 μΩ: 0,1 μΩ

 1,000 mΩ – 9,999 mΩ: 1 μΩ

 10,00 mΩ – 99,99 mΩ: 10 μΩ

 100,0 mΩ – 999,9 mΩ: 0,1 mΩ

 1,000 Ω – 9,999 Ω: 1 mΩ

 10,00 Ω - 99,99 Ω: 10 mΩ

 100,0 Ω – 999,9 Ω: 0,1 Ω

 1,000 kΩ – 9,999 kΩ: 1 Ω

Data Storage

 1 000 internal memory positions

Printer (optional)

 Thermal printer

 Paper width 80 mm

OLTC Dynamic Resistance Measurement

 Sampling rate: 4 ms

 Automatic open circuit detection and

warning

 Transition current ripple measurement

 Transition time measurement using DV-Win

software

 Timing measurement of different transition

changes using DV-Win graph analysis tool

Temperature Measurement

 One temperature measurement channel

Thermometer Pt100

-50 ºC +180 ºC / -58 ºF +356 ºF

50 mm x 6 mm

Computer Interface

 USB

 Optional: RS232

Warranty

 Three years

Environmental Conditions

 Operating temperature:

- 10 ºC to + 55 ºC / + 14 ºF to + 131 ºF

 Storage & transportation:

- 40 ºC to + 70 ºC / - 40 ºF to + 158 ºF

 Humidity 5 % - 95 % relative humidity,

non condensing

Dimensions and Weight

Device

Weight

Dimensions (WxHxD)

RMO10TW

RMO20TW

8 kg /

17.6 lbs

205 x 287 x 410 mm

8.1 x 11.3 x 16.4 in

RMO30TW

RMO50TW

8.5 kg /

18.7 lbs

205 x 287 x 410 mm

8.1 x 11.3 x 16.4 in

Mains Power Supply

 Connection according to IEC/EN60320-1;

UL498, CSA 22.2

 Mains supply: 90 V - 264 V AC

 Frequency: 50 / 60 Hz

 Mains supply voltage fluctuations up to ±10 %

of the nominal voltage

 Input power: 2 250 VA

 Fuse 15 A / 250 V, type F, not user replaceable

Applicable Standards

 Installation/overvoltage: category II

 Pollution: degree 2

 Low voltage directive: Directive 2014/35/EU

(CE conform); Applicable standards, for a

class I instrument, pollution degree 2,

installation category II: IEC EN61010-1

 EMC: Directive 2014/30/EU (CE Conform)

Applicable standard EN 61326-1

 Safety: CAN/CSA-C22.2 No. 61010-1, 2nd

edition, including Amendment 1

All specifications herein are valid at ambient temperature of + 25 °C and recommended accessories.

Specifications are subject to change without notice.

Specifications are valid if the instrument is used with the recommended set of accessories.

B-RXX0TW-305-EN, 2017-08-16

5

Order Info

Current and Sense cables with TTA clamps

Voltage Sense cables with TTA clamps

Device bag

Cable plastic case

Current connection cable with TTA clamps

Cable bag

Transport case

Test shunt

B-RXX0TW-305-EN, 2017-08-16

6

Instrument with Included accessories

Article No

Winding Ohmmeter RMO-TW

RMOXXTW-N-00

DV-Win PC software including USB cable

Mains Power cable

Ground (PE) cable

Recommended

Article No

Current cables 2 x 10 m 10 mm2 (32.8 ft, 7 AWG) and Sense cables 2 x 10 m

(32.8 ft) with TTA clamps*

CS-10-10LMWC

Current cables 2 x 10 m 2,5 mm2 (32.8 ft, 13 AWG) and Sense cables 2 x 10

m (32.8 ft) with TTA clamps**

CS-10-02BPWC

Sense cables 2 x 10 m (32.8 ft) with TTA clamps

S2-10-02BPWC

Current connection cable 1 x 5 m 10 mm2 (16.4 ft, 7 AWG) with TTA clamps*

CX-05-102XWC

Current connection cable 1 x 5 m 6 mm2 (16.4 ft, 9 AWG) with TTA clamps**

CX-05-062XWC

Transport case

HARD-CASE-ME

*Recommended for RMO30TW and RMO50TW

** Recommended for RMO10TW and RMO20TW

Optional

Article No

Test shunt 150 A / 150 mV

SHUNT-150-MK

Thermal printer 80 mm (3.15 in) (built-in)

PRINT-080-00

Cable plastic case – small size

CABLE-CAS-01

Cable plastic case – medium size

CABLE-CAS-02

Cable bag

CABLE-BAG-00

Current cables 2 x 15 m 10 mm2 (49.2 ft, 7 AWG) and Sense cables 2 x 15 m

(49.2 ft) with TTA clamps

CS-15-10LMXC

Current cables 2 x 15 m 2,5 mm2 (49.2 ft, 13 AWG) and Sense cables 2 x 15

m (49.2 ft) with TTA clamps

CS-15-02BPWC

Current cables 2 x 20 m 16 mm2 (65.6 ft, 5 AWG) and Sense cables 2 x 20 m

(65.6 ft) with TTA clamps

CS-20-10LMXC

Current cables 2 x 20 m 2,5 mm2 (65.6 ft, 13 AWG) and Sense cables 2 x 20

m (65.6 ft) with TTA clamps

CS-20-02BPWC

Sense cables 2 x 15 m (49.2 ft) with TTA clamps

S2-15-02BPWC

Sense cables 2 x 20 m (65.6 ft) with TTA clamps

S2-20-02BPWC

Current connection cable 1 x 12 m 10 mm2 (39.4 ft, 5 AWG) with TTA clamps

CX-12-102XWC

Current connection cable 1 x 12m 6 mm2 (39.4.4 ft, 9 AWG) with TTA clamps

CX-12-062XWC

Temperature sensor 1 x 50 mm (1.97 in) + 5/10/15 m (16.4/32.8/49.2 ft)

TEMP1-050-XX

IBEKO Power AB Contact

Stockholmsvägen 18 Phone: +46 70 0925 000

181 50 Lidingö, Sweden E-mail: sales@dv-power.com