Kelvin Test Pins (KWP150)
How to build them into a kelvin socket
Tools & materials required:
Drill bits required, depending on the component lead diameter:
- 3.40mm drill bit for 0.65mm diameter leads;
- 3.75mm drill bit for 0.75mm diameter leads;
- 3.90mm drill bit for 0.90mm diameter leads;
- 4.00mm drill bit for 1.00mm diameter leads.
Flat bladed screwdriver 3mm wide;
Phillips PH3 screwdriver;
15 minute epoxy or thread locking fluid;
Drilling machine;
Block material: Such as nylon, 20mm deep.
With some components, an additional top cover using a 0.8mm thick piece of FR4, will serve as a lead guide plate - as
any misalignment of the component legs during insertion can easily damage the nylon or the kelvin pins. Please drill a
suitable hole for the component leg to pass through it.
Fitment Instructions:
1.
2.
3.
4.
5.
Check that transformer lead is within the diameter range of 0.8mm to 1.3mm, and the minimum length is 2.5mm.
Check that transformer lead spacing (pitch) has minimum of 3.75mm.
Tape the card template to fixture block.
Use a marker pen to mark each component hole position onto the card.
Place the block on the drilling machine. Drill each position with a 3.4mm drill bit, drilling completely through the
block. Remove the card template.
6. Enlarge the top of the hole by drilling to the size dependant on the lead diameter (see above). Drill this no deeper
than 9.5mm.
7. It is recommended that the back of the hole is threaded, so that it gives a key for the epoxy.
8. It is also recommended that the wires should be soldered on to the pin’s terminals, then sleeved, before fitment
into the block.
9. Flip the block over to the back and insert each pin carefully, making sure it is set to the desired depth, and that any
pressure required is only put onto the plastic barrel. The 3mm screwdriver is ideal for this purpose.
10. Spread each pin’s terminals apart and fill the hole with the epoxy or thread locking fluid.
Drilling detail
KWP fitment detail
Ø slightly larger than lead diameter
3.4 - 4.0mm
²9.5
optional
guide plate
3.4mm
Thread
here
KWP150 in position
Solder wires to each tail
Epoxy
Coda Systems Ltd
Oak Road, Little Maplestead, HALSTEAD, CO9 2RT UK Tel: +44 (0)1787 478678 • Fax: +44 (0)1787 274194
[email protected] www.coda-systems.co.uk