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Marklin white transformers 6647 32 VA and Roco locos reversal
Joined: 14/10/2011(UTC)
Posts: 9
Location: Parque Leloir - Buenos Aires - Argentina
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Hi Marklin friends, this is my first message but I read you often.
I have the following issue: I have an analog (not digital) Marklin layout. With the old blue Marklin transformers 6671 16 VA all my 3 Roco digital locomotives with Roco decoders change/reverse direction perfectly.
But as I read that such transformators were dangerous for digital locos' decoders, y replaced them for the newer white Marklin transformers 6647 32 VA, and now I have the problem that the tensiony of you pulse is not enough for the Roco locomotives to reverse!
These are 230 volts transformers, for Europe, but in Argentina we seldom have even the nominal 220 volts that we should have. However, the Marklin digital locomotives that I have change fairly well with the 6647s, providing there are no bulb-lighted coaches on the track.
¿Have you ever had or hear of such problem? ¿Do you know what it may be?
Many thanks from Buenos Aires!
Orlando Musumeci
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 1 user liked this useful post by musumeci
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Joined: 16/02/2004(UTC)
Posts: 15,443
Location: DE-NW
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Hi, Orlando, Welcome to the forum. Originally Posted by: musumeci  ¿Have you ever had or hear of such problem? ¿Do you know what it may be? No. I have two comments: Roco used many different decoders over time. For a while they even advertised their decoders could withstand the reversing voltage of blue transformers up to 46.5 Volts (it's only 40 V with modern ESU or Märklin decoders [when you measure voltages with an AC volt meter: old Roco/ESU decoders are safe up to 32 V efficient voltage (which is 46.5 V peak voltage), new decoders are safe up to 28 V (which is 40 V peak voltage)]). The reversing voltage of the blue transformers made for 220 V is normally a few volts higher than it should be, especially with a mains voltage of 230 V. Are you sure the Roco locos are digital? Do you have the ref. numbers for them? Roco also made analogue locos for the three-rail system. Does the reversing fail everywhere on the layout, even on the feeder tracks? |
Regards Tom --- "In all of the gauges, we particularly emphasize a high level of quality, the best possible fidelity to the prototype, and absolute precision. You will see that in all of our products." (from Märklin New Items Brochure 2015, page 1) ROFLBTCUTS  |
2 users liked this useful post by H0
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 Joined: 23/02/2005(UTC) Posts: 800
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Hi Orlando,
If you have a mutimeter, measure the voltage of the blue transfo output, when sending the inversion comand.
If you measure 28V AC or less, you are safe, keep your blue transfo.
Fred
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2 users liked this useful post by efel
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 Joined: 28/11/2007(UTC) Posts: 8,229 Location: Montreal, QC
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The issue with transformer reverse surge and digital decoders only applies to the more recent ones in use for about a decade now. It was further complicated by changes in the voltage of the electrical networks in some parts of the world, as new standards were brought in. If using an older transformer on a network that has been boosted from 220V to 230V, this will increase the voltage output of the transformer, which can fry decoders that were not intended for such spikes.
If you are using modern decoders (ESU, Zimo, etc), you are probably better to change to one of the newer transformers.
The warning applies more to the older blue metal transformers with the push button reverse rather than to the post 1970s models where you had to turn to the left of the zero to initiate the reverse pulse.
This issue may also affect the lightbulbs on many loks and cars/coaches which are not equipped with a shutoff when the pulse is detected.
Regards
Mike C
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2 users liked this useful post by mike c
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Joined: 16/02/2004(UTC)
Posts: 15,443
Location: DE-NW
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Originally Posted by: mike c If using an older transformer on a network that has been boosted from 220V to 230V, this will increase the voltage output of the transformer, which can fry decoders that were not intended for such spikes. When using tranformers made for 220 V at 220 V the reversing voltage can still be too high for modern decoders. This warning also applies to transformers where the reversing position is to the left of the zero position (I have one of those and measured its output voltage). |
Regards Tom --- "In all of the gauges, we particularly emphasize a high level of quality, the best possible fidelity to the prototype, and absolute precision. You will see that in all of our products." (from Märklin New Items Brochure 2015, page 1) ROFLBTCUTS |
1 user liked this useful post by H0
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Joined: 14/10/2011(UTC)
Posts: 9
Location: Parque Leloir - Buenos Aires - Argentina
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Many thanks to everyone!
Regarding HO's comment, all 3 Roco problematic locomotives are factory equipped with Roco 10738 decoder and yes, it happens (or better, doesn't happen) everywhere in the layout, even on the feeder tracks.
I asked Roco but they haven't answered yet. I wonder from my ignorance: perhaps should a tension stabiliser set to a 230 Volts output solve the problem . . .?
Kind regards, Orlando
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Joined: 16/02/2004(UTC)
Posts: 15,443
Location: DE-NW
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Originally Posted by: musumeci all 3 Roco problematic locomotives are factory equipped with Roco 10738 decoder That's the one Roco advertised to be safe even with blue transformers (reversing voltages up to 32 V). A voltage stabilizer should solve the problem. OTOH if the reversing voltage of the blue transformers is below 28 V then it is within the specifications even for modern decoders. The colour blue does not make the transformers harmful - but some have too high reversing voltages, some (rather old ones) have brittle insulation. I would guess that your transformers are too young for insulation problems. But you should check the reversing voltage before using them with (modern) decoders. |
Regards Tom --- "In all of the gauges, we particularly emphasize a high level of quality, the best possible fidelity to the prototype, and absolute precision. You will see that in all of our products." (from Märklin New Items Brochure 2015, page 1) ROFLBTCUTS |
1 user liked this useful post by H0
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