PT-2Three Phase Electromechanical Watt-Hour Meter

GeneralIntroduction
The three phase four-wire electromechanicalwatt-hour meter is designed to meet the latest IEC 60521 and BS EN60521standards for measuring active energy in three-phase four-wire alternatingcurrent power grids. Connection is direct or by instrument transformers. Theaverage service life (MTTF) of the meter is 15 years and the maximal overloadcapacity is 400%Ib

Components

1. Meter case
The meter case meets the protection requirements set by IP52 of IEC 60529. Theseries types of cases and terminal covers are available.

2. Terminals
The connection terminals are made of nickel-plated brass with features of highmechanical strength, good conductivity and corrosion-resistance.

3. Terminal block
For meter of steel or PC base, the terminal block ismolded of heat-and flame-resistant bakelite. The voltage test link can belocated inside or outside of the meter case.

4. Driving system
It has three electromagnet elements. Each element consistsof a voltage element and a current element, all of which are mounted on themeter frame with two screws. Voltage coil is enwrapped in a thermoplastic caseto ensure fine insulation. In addition, the voltage element has a low loadadjustment mechanism.
The current element employs a simple and reliable load curve compensationmechanism to ensure the flat characteristic curve. An inductive load adjustmentmechanism is on it.

5. Rotor
The rotor disk is made of a hard and high purityaluminum. The rotor shaft is turned of high strength brass. There is a smallhole on the upper end for storing lubrication and for fitting a brass bearing.The lower end is cone-shaped to ensure fine guiding of the rotor.

6. Braking element
The magnet cube is made of AINiCo5 alloy and designedas U-shaped so that the effect of short-time over currents upon the magnet isnegligible. A temperature compensation plate made of a special alloy, is mounted outside of the magnet. The error of fullload can be controlled precisely by turning the adjustment mechanism.

7. Frame
The frame is die-casted by high qualityaluminum-silicon alloy of stable property to avoid distortion. The applicationof static spray-painting on the surface prevents the frame from oxidation.

8. Upper bearing
The guide pin is made of abrasion-proof stainlesssteel, and embedded into the brass sleeve.

9. Lower bearing
Both double jewel bearing and magnetic bearing areavailable.

10. Register
The cyclometer type register consists of six drums. The kWh can be readdirectly. The drum is made of polycarbonate. The framework is made of hardaluminum alloy and can be manually adjusted and fixed with two screws to insurethe proper mesh with the worm on the rotor shaft.

Technical Data

Typical connectionsdiagrams