1. Passive Component Applications
Resistor Solutions for Energy Metering 2006

2. TT electronics
Supplier of electronic and electrical components to the world’s leading companies

3. TT electronics (Components)
Resistive Components
Sensors
Hybrids
AB Sites Salzburg; Werne; Klingenburg
FE offices; Japan; Malaysia; Singapore
USA sites; Corpus Christi; Boone; Smithfield
Europe offices; UK, France, Germany, Italy
Magnetic Materials
Wound Components
Optoelectronics

4. Welwyn Components, UK
1937: Started Resistor Manufacture in Welwyn Garden City near London
1948: Moved to Northumberland, near Newcastle
1960: Started Hybrids Manufacture
1990: Acquired By TT Group
2001: TT became “TT electronics plc”

5. Welwyn Components, UK Applications Engineering Contacts
Custom & new products
Special testing
Pulse performance data
Applications support
Stephen Oxley
Direct: +44 (0)
Martin Birkett
Direct: +44 (0)

6. Passive Components Applications
Agenda
Welwyn Resistive Components for energy metering applications
Line Input Resistor
Voltage Measure
Current Sense
Lead-forming Options for lower assembly costs

7. Applications:
Industrial

8. Welwyn Applications: Industrial Energy Meters Motor Drives Power
Supplies
Lighting
Ballasts

9. Energy Meters Applications: Industrial Current Line Input Sense
Flameproof Wirewound
Low Ohmic
LRF
OAR
ULR
WP-S
Current
Sense
Line Input
Flameproof Oxide
Energy Meters
WMO-S
Precision
High Voltage
WRM RC MH
VRW
Voltage
Measure

10. WP-S Flameproof Wirewound
High Purity Ceramic Core improves axial heat spread
Welded Cap Construction
Pb-free Finish
on Cu-clad steel wire
Flameproof Cement Coat
UL94-V0 Silicone Cement
Energy absorbing winding
Custom choice of alloy & wire diameter

11. WP-S Flameproof Wirewound
WP-S Features
25% to 50% reduction in size
Custom design for specific inrush ratings
Fuses without flame or particles
Operating ambient -55 to +155°C
Sizes from 1W to 7W
Competitor Competitor WP-4S

12. WP-S Flameproof Wirewound
WP-S Features
Surface mount option – Z-form (e.g. WP2Z)
Pick & place from tape
Full wirewound rating & pulse performance in SMD format

13. WMO-S Pulse / Failsafe Oxides
Pulse withstanding fusible oxides
Defined 1.5/50us pulse performance
Defined line voltage pulse performance
Defined line voltage failsafe fusing

14. WMO-S Pulse / Failsafe Oxides
How do we get WMO-S performance?
Tin Oxide film for good pulse capacity
Careful control of laser adjustment parameters
Continual batch monitoring of pulse and fusing performance

15. High Pulse Performance

16. Energy Meters Applications: Industrial Current Line Input Sense
Flameproof Wirewound
Low Ohmic
LRF
OAR
ULR
WP-S
Current
Sense
Line Input
Flameproof Oxide
Energy Meters
WMO-S
Precision
High Voltage
WRM RC MH
VRW
Voltage
Measure

17. Compact high voltage MH/VRW
Sizes -25 (1.6kV) & -37 (3.5kV)
Small size
High pulse load capability
MH thin film, VRW thick film
Value up to 30M

18. MELF for high accuracy – typically 4 to 6 parts in series
Compact precision WRM
MELF for high accuracy – typically 4 to 6 parts in series
0102 / 0204 / 0207 sizes
High stability metal film
Ideal for measurement circuits
TCR to 5ppm
Tolerance to 0.1%

19. Precision Through-Hole

20. Energy Meters Applications: Industrial Current Line Input Sense
Flameproof Wirewound
Low Ohmic
LRF
OAR
ULR
WP-S
Current
Sense
Line Input
Flameproof Oxide
Energy Meters
WMO-S
Precision
High Voltage
WRM RC MH
VRW
Voltage
Measure

21. LRF Series Current Sense
LRF Features
Low ohmic values to 3mW
Power rating to 3W
Higher thermal conductivity than metal strip
Lower inductance than capped metal strip
Also LRZ zero ohm jumpers to 35A
Now includes smaller sizes to 0402 as LRCS

22. LRF Series Current Sense
Low thermal impedance gives lower temperature rise
Thermal photographs of 2010 parts at 1W
Metal Strip LR
83°C/W
58°C/W
Using 200mm2 pad / trace areas as heatsink

23. OAR Series Current Sense
OAR Features
Compact metal element shunt
Power rating to 5W, values from R005
Welded copper terminations

24. ULR Series Current Sense
ULR Features
Ultra-low ohmic values to 0.5mW
Power rating to 3W
Low inductance welded metal strip
New

25. Standard Lead-forming Options

26. Application Note

27. The End
Thank you!
Any questions?