Product Description
General
The DD862 single phase meter is designed to meet the latest IEC 60521. With accuracy of class 2, it measures active energy in single-phase two-wire or three-wire alternating power grids. Connection is direct or by instrument transformers. It is a reliable long service life meter. The average service life (MTTF) is 15years and the maximal overload capacity is 667%Ib. The specifications of the meter can be tailored to customer requirements.

Construction
1 Meter case
Two types of the cases are available.
2 Terminal block
The terminal block is molded of Bakelite.
3 Driving element
The driving element consists of a voltage element and a current element, both of which are fixed on the steel frame of fine magnetic conductivity. It has a load curve compensation device, low load and inductive load adjustment mechanisms.
4 Rotor
The worm is an un-detachable part of the rotor shaft so that the mesh between the worm and shaft is improved. Both ends of the shaft are embedded with graphite bearing to ensure the long service life of the meter.
5 Braking element
The magnet is made of AlNiCo5 alloy and designed as U-shaped so that the effect of short time over currents upon the magnet is negligible.
6 Frame
The frame is made of high-quality steel. Its surface is treated by negative electrophoresis to achieve excellent corrosion-proof.
7 Register
The register adopts heat- and abrasion-proof plastic gears and bearings. No lubrication of bearings is needed during the service life...

Technical data
1. Applicable Standards IEC60521
3. Accuracy Class 2(according to IEC60521)
4. Average service life (MTTF) 15 years
5. Basic current (Maximum current) A 1.5(6) 3(6) 5(20)10(20) 20(40) 10(60) 15(60)30(60) 20(80) (special curreny as required)
7. Rating current of transformer in 5A direct connection
8. Reference voltage Un 110V, 120V, 220V, 230V, 240V
9. Reference frequency fn 50 Hz, 60 Hz
10. Power losses in voltage circuit at 50 Hz Un 1.0 W/5 VA
11. Power losses incurrent circuit at 50Hz Un Ib<0.6 VA
12. Non-running with no-load 0.8~1.1Un
13. Staring current 0.5%Ib
14. Mean temperature coefficient: From 0.1Ib to Imax at unity PFFrom 0.2Ib to Imax at unity 0.5 lagging<0.08%/oC<0.12%/ oC
15. Insulation level: Withstand A. C. Voltage for 50 Hz, 1min Withstand impulse voltage 1.2/50us>2 kV (when bakelite base>4kV)>6kV (when bakelite base>8kV)
16. Rated load torque at unity PF, Ib 450uNm
17. Meter base Bakelite or steel
18. Meter cover Bakelite or transparent PC
19. Terminal cover Bakelite or PC