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Discussion Starter · #1 ·
Since converting from DC to DCC my locos now appear rather slower than previous. Before I get my stopwatch out or try and measure the DC being fed to the motor I was wondering whether anyone else has suffered the same experience?

I have an Elite with all hornby decoders fitted to a number of locos including hornby class 31, bachmann super voyager, old HST.

All my track is new peco code 75 and every piece is fed from a bus running under the layout so I hope the electrical supply is as good as it can be. The bus does not have any resistor loads on the ends but they are maximum 5m in length and supply an isolated section of track (i.e. dont overlap with other bus regions)

I do not yet have any other types of decoder but would like to test it with a lenz gold. I also don't have access to any other DCC system to try the locos on that.

I have seen posts that suggest that the ac voltage the elite supplies to the track is lower than some other DCC systems but I do not know enough about the way the dcc decoders convert this to DC to understand if this could have an impact on the peak power supplied to the motor.

If anyone has any ideas about how I could test this then I would love to hear from you. However I only have a basic digital meter (no scope etc)

Also if anyone has any comparisons between decoders or dcc systems in terms of voltage supplied or loco performance then I would be interested.

I do plan to try things out with my Gaugemaster DC but its only my class 31 that has a socket so all the other decoders are soldered. I have tried to source some sockets that I can solder to circuit boards to accept decoder plus but have not found a supplier to date.

Fazer
 

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QUOTE (fazer @ 11 Jun 2007, 19:40) <{POST_SNAPBACK}>Since converting from DC to DCC my locos now appear rather slower than previous. Before I get my stopwatch out or try and measure the DC being fed to the motor I was wondering whether anyone else has suffered the same experience?

I have an Elite with all hornby decoders fitted to a number of locos including hornby class 31, bachmann super voyager, old HST.

All my track is new peco code 75 and every piece is fed from a bus running under the layout so I hope the electrical supply is as good as it can be. The bus does not have any resistor loads on the ends but they are maximum 5m in length and supply an isolated section of track (i.e. dont overlap with other bus regions)

I do not yet have any other types of decoder but would like to test it with a lenz gold. I also don't have access to any other DCC system to try the locos on that.

I have seen posts that suggest that the ac voltage the elite supplies to the track is lower than some other DCC systems but I do not know enough about the way the dcc decoders convert this to DC to understand if this could have an impact on the peak power supplied to the motor.

If anyone has any ideas about how I could test this then I would love to hear from you. However I only have a basic digital meter (no scope etc)

Also if anyone has any comparisons between decoders or dcc systems in terms of voltage supplied or loco performance then I would be interested.

I do plan to try things out with my Gaugemaster DC but its only my class 31 that has a socket so all the other decoders are soldered. I have tried to source some sockets that I can solder to circuit boards to accept decoder plus but have not found a supplier to date.

Fazer
hi frazer,all decoders covert ac, to 12vdc so it does not matter about ac supply,i have the elite and all my locos run ok,with hornby,nce,lenz&bachman decoders,i can only sugest tryingdifferent settings in your cvs.
 

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QUOTE (owen69 @ 12 Jun 2007, 09:50) <{POST_SNAPBACK}>hi frazer,all decoders covert ac, to 12vdc so it does not matter about ac supply,i have the elite and all my locos run ok,with hornby,nce,lenz&bachman decoders,i can only sugest tryingdifferent settings in your cvs.

No, the decoder does not regulate the voltage to 12V. The voltage available to drive the motor depends upon the track voltage. It's not easy to measure the (AC) track voltage since most hobby multimeters are only calibrated for 50Hz sine waves. The easiest way to measure it is between one of the decoder's function outputs and the blue wire, when the function is on. Add 1 - 2V to allow for the voltage drop across the rectifier.

Andrew
 

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QUOTE (owen69 @ 12 Jun 2007, 09:50) <{POST_SNAPBACK}>hi frazer,all decoders covert ac, to 12vdc so it does not matter about ac supply,i have the elite and all my locos run ok,with hornby,nce,lenz&bachman decoders,i can only sugest tryingdifferent settings in your cvs.
No they don't. All they do is take whatever the track supply level is, drop a bit of voltage through their bridge rectifier, and use whatever is left for the motor supply. There is normally no on-board regulation of actual supply voltage on the motor side, only to the logic/processor circuitry. I believe many commercial command stations provide a facility for adjusting the voltage level applied to the track, but I don't know if the Elite allows this or not.
 

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Discussion Starter · #6 ·
Thanks for the help.

Does anyone know if there are CVs that affect the top speed / voltage getting to the motor?

Has anyone also tested the power efficiencies of different decoders to see is some allow more DC voltage to reach the motor?

Sorry for all the questions..... will changing the separate power supply for the elite make any difference or does the elite regulate the input voltage from the power supply?

I'll post the speed timings when I have a chance to do the test but thats likely to be at the end of the week.

Fazer
 

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QUOTE (fazer @ 12 Jun 2007, 20:20) <{POST_SNAPBACK}>Thanks for the help.

Does anyone know if there are CVs that affect the top speed / voltage getting to the motor?
CV5 (Vhigh) and CV67-94 (speed table) affect the maximum speed of the motor. CV29 bit 4 (using proper bit numbering 0 - 7) determines whether the speed table is used.

See http://www.nmra.org/standards/DCC/standards_rps/rp922.html in conjunction with the instructions for the particular decoder you are using.

Andrew
 
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