DCC Engines Running Too Slow

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mmmbeeer
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DCC Engines Running Too Slow

Postby mmmbeeer » Wed Oct 31, 2012 9:56 am

Hi all, I'm new to this forum and this is my first post. I'm after DCC advice. I am slowly building up a fleet of DCC controlled engines using a Hornby Elite controller and Hornby 8 pin decoders. Some engines were DCC ready and some not. Some of the engines can attain something like their former top speed when running on DC while others run really slowly. All the decoders are set to default settings so should perform the same. Should I adjust CV5?
Cheers for any help
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Flashbang
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Re: DCC Engines Running Too Slow

Postby Flashbang » Wed Oct 31, 2012 10:20 am

Hi
CV5 set to its maximum will give the maximum volts to the motor when the top speed setting is reached on the DCC console.
So if any CV5 values are found to be set lower than maximum available and you need the locos to run faster at top speed setting, then set CV5 to its maximum.

If CV5 is already at its maximum and the loco is slow other than checking for any binding and serving the loco, you cant make it any faster.
But normally setting the top speed value in CV5 to maximum will be about right for many, if not all locos, as they are not meant to hurtle around the layout like a racing car, but are running at often a greater scale speeds than the real things can do anyway!
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Bigmet
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Re: DCC Engines Running Too Slow

Postby Bigmet » Wed Oct 31, 2012 10:47 am

There are some known slow locos out there. I cannot get any of Bachmann's BR std 5 and 9F, V2 and class 37 to achieve the scale maximum speed they were capable of, without significantly raising the output voltage of my DCC system, which I don't really want to do. Most locos have no trouble getting to scale maximum speed: these 'slow' examples all have higher than usual reductions from the supplied gear set - great for low speed control - which limits the top end speed. Altering the gear set is one way forward.

I have also twice encountered what I think of as 'lazy' decoders which failed to increase output at the higher speed steps, and which were not cured by resets to factory settings or any other action available on their CV set. If you feel like doing the experiment of exchanging decoders between what are currently fast and slow chassis, and you find the performance moves with the decoder... We don't often discuss decoder variability, but it is definitely possible as with any manufactured product, even though electronics are typically much more stable example to example than mechanical systems.

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mmmbeeer
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Re: DCC Engines Running Too Slow

Postby mmmbeeer » Wed Oct 31, 2012 11:04 am

Thanks Flashbang and Bigmet for your responses. I'll try reading and changing CV5 tonight to see if that does anything. I'll have some new decoders soon so I can try changing them if CV5 don't answer. All provided she who must be obeyed hasn't lined up other things to occupy my time.
East Coast Main Line expresses are supposed to go faster than 30mph aren't they?
Cheers

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Re: DCC Engines Running Too Slow

Postby Essex2Visuvesi » Wed Oct 31, 2012 11:08 am

as you are using an elite download the JMRI software and connect your PC to the Elite
http://jmri.sourceforge.net/

Within the JMRI package is a program called decoder pro which you can use to program CVs.
A very useful feature of Decoder pro is the ability to "backup" the deocoder settings to the PC, so If you bugger it up you can just reset them back to the last backup

Another bonus is its FREE!
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mmmbeeer
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Re: DCC Engines Running Too Slow

Postby mmmbeeer » Wed Oct 31, 2012 11:11 am

Just remebered, read somewhere on t'internet - "on dcc engines recommend removing the suppressor capacitor as the decoder will provide suppression and engine will run better". Could make sence- a capacitor across the feed to the motor could shunt some of the pwm signal????

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Re: DCC Engines Running Too Slow

Postby Essex2Visuvesi » Wed Oct 31, 2012 11:13 am

capacitors usually affect the slow running if memory serves, but it cant hurt to give it a try

What are the locos you are having issues with?
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Re: DCC Engines Running Too Slow

Postby mmmbeeer » Wed Oct 31, 2012 11:16 am

Essex2Visuvesi wrote:as you are using an elite download the JMRI software and connect your PC to the Elite
http://jmri.sourceforge.net/

Within the JMRI package is a program called decoder pro which you can use to program CVs.
A very useful feature of Decoder pro is the ability to "backup" the deocoder settings to the PC, so If you bugger it up you can just reset them back to the last backup

Another bonus is its FREE!



I like the sound of that and will definitely have a look. Really starting to be glad I joined this forum!

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Re: DCC Engines Running Too Slow

Postby mmmbeeer » Wed Oct 31, 2012 11:20 am

Essex2Visuvesi wrote:capacitors usually affect the slow running if memory serves, but it cant hurt to give it a try

What are the locos you are having issues with?


One is a Hornby Mallard, can't remember model number but it was a limited edition, one is a Hornby Railroad Falcon, both bought second hand on eBay. They're only managing scale speeds of 20-30 mph pulling 4 coaches.

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Re: DCC Engines Running Too Slow

Postby Essex2Visuvesi » Wed Oct 31, 2012 11:24 am

Well worth a look.
If you are prepared to spend a little time on it then JMRI is a really powerful peice of kit
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mmmbeeer
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Re: DCC Engines Running Too Slow

Postby mmmbeeer » Wed Oct 31, 2012 11:33 am

Essex2Visuvesi wrote:Well worth a look.
If you are prepared to spend a little time on it then JMRI is a really powerful peice of kit


I was thinking of buying the Hornby dcc control software, so I looked at the trial version. It was very retro but worked OK. At first glance the JMRI suite could offer a free solution instead?

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Re: DCC Engines Running Too Slow

Postby Essex2Visuvesi » Wed Oct 31, 2012 11:41 am

yes it can do everything that railmaster can and then some, but it does take a little more setting up

There's a couple of us on here that use it and also the JMRI forum is a mine of useful information as well
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mmmbeeer
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Re: DCC Engines Running Too Slow

Postby mmmbeeer » Wed Oct 31, 2012 11:57 am

Looks like the JMRI Layout Editor can do occupancy as well as controlling engines, turnouts, signals, etc. I'll definitely take a look at the JMRI forum. Well I think that's gonna save me 50-60 quid which my wife will definitely approve of.

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Re: DCC Engines Running Too Slow

Postby Essex2Visuvesi » Wed Oct 31, 2012 12:02 pm

mmmbeeer wrote:Well I think that's gonna save me 50-60 quid which my wife will definitely approve of.

Please send payment to...... :D
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Re: DCC Engines Running Too Slow

Postby Flashbang » Wed Oct 31, 2012 12:12 pm

mmmbeeer wrote:One is a Hornby Mallard, can't remember model number but it was a limited edition, one is a Hornby Railroad Falcon, both bought second hand on eBay. They're only managing scale speeds of 20-30 mph pulling 4 coaches.

Hi again
Now we have determined the slow runners are second-hand locos, can you say whether they are tender drive or the motors are in the locos body?
Set CV5 to it maximum setting then...

Fully service these loco(s) - clean and lubricate all parts including wheel treads and then apply the tinniest drop of model railway oil - Not 3 in 1 or any spray lubricants like WD40, to all pivots including the motor bearings at the front and rear of the motor. Apply special grease to the gear train if it was greased originally. Special model railway oil and grease are sold by all good model shops.

While the body (or tender if tender drive) is off, remove all the RF interference capacitors which can effect the Bemf control between the decoder and motor. Note; removing RF capacitors will never make a DCC loco run worse but their remove may make it run better!

Check all free moving parts are actually free to move. Once all is lubricated and cleaned run it in, in a forward direction for some 15 minutes at a medium speed then in reverse again for 15 minutes, doing this in both directions as a light loco - without any load add - No carriages or wagons etc.

Then see what the top speed is like.
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