TRANSDUCERS FOR AC CURRENT AND VOLTAGE |
The transducer converts an AC current or voltage into a load independent DC current or voltage signal which may be used to drive a number of remotely installed instruments.
The measuring principle is "arithmetic mean calibrated to RMS sinusoidal" and this transducer is therefore only suitable for undistorted sine wave measurements.
The normal response time is suitable for indicating instruments and recorders. A lower ripple - slower response version for data loggers can be supplied.
The output is protected against over-voltages due to surges or accidental contact with insulation testers.
Internal jumpers allow selecting either 110V or 220V AC auxiliary supply.
The current/voltage to be measured is transformed in (1) and converted in the active rectifier(3). The auxiliary supply is transformed in PT(2), rectified and smoothed in (4) and is used to power the rectifier (3), output amplifier (5) and to provide the offset voltage for the live zero version. The output amplifier (5) provides either a load independent current (with maximum burden) or a load independent voltage (with minimum burden) signal.
| 1. Input | |
| Input quantity: |
0 - 1 A or 0 - 5 A 0 - 120 / 250 / 500 / 600V. Other values on request. |
| Frequency: | 45 - 55 - 65 Hz |
| Consumption burden: | 0.3VA at rated input |
| Overload in terms of rated input |
1.2x indefinitely Current:40x 0.5 seconds Voltage: 2x 10 seconds |
| 2. Output | |
| Characteristic: | Live zero |
| Output quantity: | Impressed current signal |
| Standard value: | 0 - 20mA or 4 - 20mA |
| Maximum load: | 500 Ohm |
| Maximum output current: |
1.25x rated (typical) 2.0x rated (maximum) |
| Ripple: | 0.5% standard |
| Response time: | 210ms standard |
| 3. Auxiliary power supply | |
| 110V or 220V AC 50 Hz | |
| 4. Accuracy | |
| Error limit at rated conditions: | ±0.5% of range at 23°C and 45-55 Hz sinusoidal wave, form factor 1.11 |
| Linearity error: | 0.05% |
| Long term drift: | 0.25% |
| Temperature shift: | 400ppm/°C |
| Variation with auxiliary supply: | 0.05% for ±20% variation |
| 5. Protection | |
| Impulse test between isolated sets of terminals: | 5kV (0.5J 1.2/50 wave) IEC standard |
| Voltage withstand rating between sets of terminals: | 4kV, 50Hz AC for 1 minute |
| Surge across output terminals: | 25J 1 x 8/20 micro seconds |
| 6. Physical constraints | |
| Working temperature: | -25 to 13 to 33 to 55°C |
| Storage temperature: | -55 to 75°C (above dewpoint) |
| Relative humidity: | 80% |
| Variation due to external magnetic field (worst case): | 0.05% at 400A/m 50Hz |
| Position: | Surface mounting in any position indoors. |
| 7. Enclosure | LDG6 |