Graham-Farish chassis safely to DCC in minutes!
Q. So, the spring is a fuse?
A. No. The spring is made from 0.32mm (28awg) Beryllium
copper wire, which has a capacity of 1.4 amps. Or, put another way, most
'N' gauge decoders provide 0.8 -1 amps. The current draw of an
average Farish motor is 0.3 - 0.4 Amps.
Q. OK then, will heat draw the
temper of the spring?
A. No. Beryllium copper is tempered at 460°
C for an hour. With a loading of 1 amp the
temperature increase of the spring is negligible. (see below)
Q. Does the spring get hot?
A. No. At 1amp heat generation is 0.003 W/second (per
1000m of wire!), heat dissipation is 105 W/m*k, again, well within
Q. Will the DiGi-Hat™ melt?
A. No. The material has a melting point of 140°C.
Q. Is it true the DiGi-Hat™ absorbs
water, expands, and splits?
A. No! The material used (a copolymer of Polyoxymethylene) is
designed for use as a bushing material, and is specified at less than
0.5% absorption at 100% immersion. (measured by ISO 62-Sat/23C) - and after all, we're not discussing
Q. What makes this the best solution?
A. DiGi-Hat™ is a designed and engineered solution. It uses
high quality materials chosen specifically for the task, and
engineered by a specialist company with over 35 years of experience,
under compliance with BS EN ISO 9001 : 2000
Designed by DCC Supplies.
Typical chassis are the old 'Poole' built
diesel's, and most steam locos (No special kits are required
for modern diesel chassis) and the challenge to a DCC conversion is the fact
that the motor brush is built into the live chassis. A
brass 'top hat' provides the housing for the carbon brush,
and in turn is held in place by a sprung brass clip,
providing electrical connectivity to the brush, from the
There have been a number of attempts
in the past to solve this problem, different methods for
steam and diesel chassis, but all involving a major strip
down, machining and the application of easily damaged or
degradable insulation materials, or application of paint as
Ultimately, with these kits, success is dependent on the
skill of the fitter, and the amount of care, and time that
is able to be invested as once drilled, a chassis can easily
be damaged beyond repair.
SO After considerable
thought and research, we designed our own modification,
which is now available for sale - the DiGi-Hat™ is
a carefully thought out solution, fully researched, from the
careful, informed choice of materials, to precision
engineering tolerances in production. Our manufacturer is an
industry leader in insulation and plastics engineering, and
have been fully involved in the project from the start.
Using the spring as a conductor is quite within its current
carrying capacity (see sidebar), also worth noting is that
some decoder manufactures use 28AWG wire for motor and
accessory connections on some decoders rated over 1amp.
We now use only Kynar® sleeving, which being a
mere 0.5mm thick, avoids the problem found on certain steam
locomotives where standard tubing fouls the wheels, and
therefore removes the need for filing. Amazingly this
material has more abrasion resistance than standard
heat-shrink, so is more resistant to tearing during
disassembly, no risk, 100% retrofittable, no drilling, no
painting, and easy conversion back to DC. (keep the value of
DiGi-Hat™ is a direct replacement for the existing brass
guide, and with the provided heat-shrink sleeve enables you
to make an extremely professional job of a DCC conversion,
better still, it takes
5, rather than 45 minutes to convert a
loco, and there is no drilling, additional materials,
or irreversible modifications required!
By simply removing the
'old' brass brush guide, inserting the insulating
DiGi-Hat™ and adding the heat shrink sleeve to the clip, all
that is then needed, is a wire soldered to the exposed
section of the clip, and fed through to the decoder.
We can provide a modified clip for those who wish to
save even more time!
The DIGI-HAT fits all Poole style
chassis, which are most of the range steam and diesel
locomotives (newer Diesels do not need this kit), if the
motor brush is held in place by a brass clip, then this kit
of many Graham-Farish Diesels will be eased by the use of
a pair of DiGi-Hat™, as the top guide also requires insulating
from the conductive brass strip, The DiGi-Hat™ has been
designed to work here as well, in this case, no additional
insulation of the clip is required, although a wire must be
soldered to the top, and connected to the decoder.
The Digi-Hat™ is available as an
individual component, with Kynar® heat shrink sleeve
included to insulate the clip, or in a kit,
with a modified clip (with attached wire, either orange or
grey to NMRA Standard)
Of course, all our Farish
conversions now use this system, and whomever converts
it, you can be assured that you've fitted a quality product
from DCC Supplies.