Ferrite Man and Digital conversion

[96RAF]

Basic question from a Hornby train user. I trust this is the correct section but I don’t know the exact difference between the various Scalextric systems, - digital, ARC, etc. Your mods can move it if required.

 

When we convert a loco to digital (install a DCC (Digital Command Control) decoder) it is common practice to remove all suppression components from the motor side of the decoder. Any suppression on the track side is always removed anyhow as it can distort the bi-polar 1-0 binary DCC signal.

 

I notice that in the slot car world ferrite man tends to be left in place and also replaced if it goes wrong. There is a lot of science behind getting the correct ferrite sleeve matching versus the capacitors used, etc so there is likely  some scientific merit for leaving the device in place post digital conversion.

 

Pre digital conversion...

 

The output from our decoders is PWM (pulse width modulation) at 12VDC to the motor and I wondered if car decoders output the same control method and if so why you leave suppression in place whilst we remove it.

 

Thanks for any help with this.

Rob

[woodcote]

Hi Rob - the Scalextric Sport Digital (SSD) system is pretty much DCC adapted for racing. The cut and thrust (and speed) of slot car racing, lane changing, crashes etc means that there is a lot more arcing and electrical 'noise' than on a well-laid DCC layout and this risks issues with the chip losing its ID or more permanent damage. I am pretty sure that's why we find the ferrite filters either side of the chip are necessary.

 

One issue with SSD is that the default setting for the chip is analogue mode, only shifting to digital when it senses a digital command signal through the rails. So the chip is prone to power surges (there is constant 15V AC to the track rails) after the digital signal is lost (on lane-changers, poor track connections, dirty track etc). Some chip versions behave better than others and having ferrite men and using INOX MX3 both help with potentially disastrous full-speed 'runaways'.

 

A more detailed, technical answer to why we use suppression and model railroaders don't is best left to electronic experts...

[96RAF]

Thanks for the explanation Andy

We railway types tend to disable DC running (analogue mode) as default because invariably it causes uncontrolled runaway if the DCC signal is lost and we try to avoid hi-speed crashes at all costs.

 

Although most of our controllers can run a single analogue loco we generally avoid even placing a DC loco without a decoder on a DCC track due to likelihood of motor burnout from the constant pseudo 15vAC track voltage.

 

INOX-mx3 looks like a useful product that would be safe for locos. We always advise against 3-in-1 and WD-40 products due to possible plastic or paint damage and gumming up, in favour of proper model oil or even sewing machine oil if our local household management stocks it. That could be a handy substitute.

Rob

[gorp]

When repairing broken lead wires at the guide end (a common repair here),

the front ferrite man is removed.

Have never noticed a difference between those with or without it at guide.

Of course the one on the motor is left on because why change what is working.

[Blane-1213263]

Where can I purchase the. Ferrite man?

[Andy P.]

At the Ferrite man shop. :-D

sweat_smile

Just kidding... there is a long thread at slotforum.com on how to do it and I have seen them a well known auction site.

I guess also Sclextric Restorations UK (I think that is their name) would have them as well...