Three tests in 1.4 kg: ratio, winding resistance and demagnetization
TWR-H
Transformer Ratio Meters
TWR-H
Handheld turns ratio and winding resistance tester
Distribution and instrument transformer testing with a pocket-sized device.
Three tests with a single connection
This battery-powered handheld device measures the turns ratio together with excitation current and phase shift, measures winding resistance and demagnetizes the core, all with the same cable set. The deviation from the nameplate ratio is calculated automatically.
Two DC current sources
One source of up to 2 A tests the high-voltage winding and another of up to 10 A the low-voltage one: each winding of a distribution transformer is measured with the right current, even simultaneously.
Main features
- Ratio test voltage of 40, 10 or 1 V AC.
- 1 V AC to verify current transformers without saturating them.
- Turns ratio from 0.8 to 20 000.
- Winding resistance from 1 µΩ to 3 kΩ.
- Automatic demagnetization after the resistance test.
- Replaceable Li-Ion battery: a full day of testing.
- Only 1.4 kg; IP67 inside its closed case.
Applications and software
Applications
- Turns ratio of distribution transformers.
- Ratio and polarity verification of instrument transformers.
- Winding resistance of transformers, motors and generators.
- Excitation current and phase angle.
- Demagnetization of transformers, motors and generators.
PC software for control and analysis
Stored results are transferred over Bluetooth to the included PC software, which allows analysing them at the office, printing them and creating customized test reports.
Memory for 100 transformers
The internal memory organizes up to 100 transformer records, each with up to 15 resistance and 15 ratio results, so a complete field campaign fits in the device.
TWR-H�—�MEASUREMENT�DATA
| Measurement | Range | Resolution | Typical accuracy |
|---|---|---|---|
| Turns ratio at 40 V AC | 0.8 – 20 000 | 5 digits | ±0.1% (0.8–999); ±0.15% (1000–3999); ±0.25% (4000–14 999); ±0.3% (15 000–20 000) |
| Turns ratio at 10 V AC | 0.8 – 20 000 | 5 digits | ±0.2% (0.8–3999); ±0.25% (4000–14 999); ±0.3% (15 000–20 000) |
| Turns ratio at 1 V AC | 0.8 – 4000 | 5 digits | ±0.2% |
| Excitation current | 0 – 1 A | 0.1 mA | ±(1% of reading + 0.5 mA) |
| Phase angle | 0 – 360° | 0.01° | ±0.06° |
| Winding resistance | 1 µΩ – 3 kΩ | 1 µΩ to 1 Ω by range | ±(0.5% of reading + 0.5% FS) |
Test sources: 40/10/1 V AC; 2 A DC (HV side) and 10 A DC (LV side).
Specifications valid at +25 °C. The manufacturer reserves the right to change them without prior notice.
| C/ María Barbeito, 14 | Contact Contact +T [+34] 982 20 99 20 |
|---|---|
| 27003, Lugo, Spain | +T [+34] 982 20 99 20 info@amperis.com | www.amperis.com |
TWR-H�—�TECHNICAL�SPECIFICATIONS
| Type | Handheld turns ratio and winding resistance tester |
|---|---|
| AC source | 40, 10 and 1 V AC |
| DC sources | Up to 2 A (HV side); up to 10 A (LV side) |
| Battery | 14.8 V, 2.9 Ah Li-Ion, rechargeable and replaceable; up to 100 tests |
| Mains adapter | 90 – 264 V AC, 50/60 Hz |
| Display | 4.8-inch LCD, 240 × 128 pixels |
| Memory | 100 transformer records, up to 30 results each |
| Communication | Bluetooth to PC |
| Operating temperature | -20 to +55 °C; storage -40 to +70 °C |
| Protection | IP40 (device); IP67 in the closed case |
| Dimensions and weight | 170 × 310 × 58 mm; 1.4 kg |
| Standards | IEC 60076-1, IEEE C57.152, CIGRE 445; EN 61010-1; EN 61326-1 |