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High Frequency Track Cleaners, the science behind them


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Hi guys, hope you are all well.

 

I recall an article some years back that actually looked into the science behind these units, they are in fact electronic continuity maintainers, not cleaners but for our purposes they work :)

But I was looking for the article and can not find it, I wanted to be sure about the frequency used (or range) and the actual voltage.

I'd assume the voltage to be around 50v and a frequency of around 1Khz or so.

 

Can anyone confirm please? 

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2 hours ago, mikesndbs said:

Hi guys, hope you are all well.

 

I recall an article some years back that actually looked into the science behind these units, they are in fact electronic continuity maintainers, not cleaners but for our purposes they work :)

But I was looking for the article and can not find it, I wanted to be sure about the frequency used (or range) and the actual voltage.

I'd assume the voltage to be around 50v and a frequency of around 1Khz or so.

 

Can anyone confirm please? 

I can't remember now, but the voltage is much higher than that - at least 300 Volts from memory. That explains why they MUST NOT be used in anything that has 'smart electronics', such as a DCC chip.

 

Useful only on old tech model trains, such as Tri-ang or Hornby Dublo. Modern stuff, don't bother.

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Posted (edited)
10 minutes ago, kevinlms said:

Useful only on old tech model trains, such as Tri-ang or Hornby Dublo. Modern stuff, don't bother.

What about modern stuff which doesn't have a chip, lights or TTS sound etc ? Just the widget which stops it scrambling the telly (capacitor?). That's my entire fleet. 

Edited by Wheatley
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Posted (edited)
20 minutes ago, Wheatley said:

What about modern stuff which doesn't have a chip, lights or TTS sound etc ? Just the widget which stops it scrambling the telly (capacitor?). That's my entire fleet. 

 

The 'widget' is a capacitor connected across the motor terminals and designed to absorb / dampen any high frequency noise from the motor which might end up being radiated into the air bu the wires and tracks thus interfering with broadcast frequencies.

 

Out in the real world Capacitors don't generally like being subjected to high voltages outside their operating range. Many a S&T tech has found that out the hard way when attempting to insulation test an Impedance bond on an AC frequency based track circuit but neglecting to remove the tuning capacitor first.

 

Thus its in theory entirely possible to damage the interference suppression capacitor with a 'high frequency track cleaner' - but provided said capacitor doesn't fail to a short circuit condition then there will be no obvious sign of this as a bog standard DC motor is not frequency sensitive. Thats why you can snip it out and not usually suffer any issues - but as Manufacturers are legally obliged to prevent interference they must still be fitted.

Edited by phil-b259
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48 minutes ago, kevinlms said:

I can't remember now, but the voltage is much higher than that - at least 300 Volts from memory. That explains why they MUST NOT be used in anything that has 'smart electronics', such as a DCC chip.

 

Useful only on old tech model trains, such as Tri-ang or Hornby Dublo. Modern stuff, don't bother.

 

Hi

 

I measured the output on my oscilloscope today, I got 50V with 800Hz frequency?

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17 minutes ago, mikesndbs said:

 

Hi

 

I measured the output on my oscilloscope today, I got 50V with 800Hz frequency?

 

Thats easily enough to kill an Integrated circuit (chip) - but won't probably cause damage to an old fashioned 'dumb' suppression capacitor.

 

 

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The point is the RF suppressor is directly across the motor, which to all intents and purposes is a short circuit. It will never be subjected to the output of the high frequency cleaner. If the motor is connected to the rails then the cleaner will not be operating. 

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On speaking to GM tech the point was made that the capacitor will block the HF cleaner signal from getting to the motor commutator etc. 

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1 minute ago, mikesndbs said:

On speaking to GM tech the point was made that the capacitor will block the HF cleaner signal from getting to the motor commutator etc. 

 

As the capacitor is fitted in parallel with the motor, then it cannot 'block' anything reaching the motor.

 

What capacitors can do is act as a short circuit to an AC voltage and diverted said voltage away from the motor.

 

 

 

 

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6 hours ago, mikesndbs said:

.......I recall an article some years back that actually looked into the science behind these units, they are in fact electronic continuity maintainers, not cleaners but for our purposes they work :).....


I once read the comment that they were the electronic hand of god. Designed to give a little push along help.

 

 

.

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On 05/07/2020 at 19:45, mikesndbs said:

But I was looking for the article and can not find it, I wanted to be sure about the frequency used (or range) and the actual voltage.

I'd assume the voltage to be around 50v and a frequency of around 1Khz or so.

 

Can anyone confirm please? 

I know the relco unit I had put out about 50V according to some printed material but I have no idea of frequency.

There were others available (DIY?) whose outputs ranged up to 1kV. 

Even some claimed to be DCC decoder compatible.  I have vague memories about a couple of mV limit and some mods to commercial units.

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