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soren36		#1 Posted : 08 September 2006 17:38:08(UTC) Retweet
Joined: 25/03/2006(UTC) Posts: 858 Location: Connecticut, USA		I bought an 18 va transformer (cheap - new from a starter set) to power my switches and uncouplers. The M* literature refers to brown and yellow leads but the trafo (M* - it has a plug) has a black lead and a black/white striped lead. My guess is the black is the brown equivalent, and the striped the yellow. Correct? Thanks - Hal
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kgsjoqvist		#2 Posted : 08 September 2006 17:56:05(UTC) Retweet
Joined: 04/06/2002(UTC) Posts: 754 Location: Täby		All old Märklin trafos give AC power, but the 18VA is a DC power source. For powering accessories it doesn't make any difference, so you can choose to use one of the leads as yellow and the other as brown. Since all accessories are made for AC, they are independent of the direction of the current.
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soren36		#3 Posted : 08 September 2006 19:49:31(UTC) Retweet
Joined: 25/03/2006(UTC) Posts: 858 Location: Connecticut, USA		Many thanks, Karl.
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MärCo		#4 Posted : 08 September 2006 20:44:09(UTC) Retweet
Joined: 06/03/2005(UTC) Posts: 1,159 Location: The Netherlands		Quote: [size=1" face="Verdana" id="quote]quote:Originally posted by kgsjoqvist <br />All old Märklin trafos give AC power, but the 18VA is a DC power source. For powering accessories it doesn't make any difference, so you can choose to use one of the leads as yellow and the other as brown. Since all accessories are made for AC, they are independent of the direction of the current. I am in very much doubt of your answer. With DC polarity does matter, with AC not. I still think the 18VA adapter is AC.
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Gert-Jan		#5 Posted : 08 September 2006 21:47:55(UTC) Retweet
Joined: 29/04/2005(UTC) Posts: 777 Location: Netherlands		Quote: [size=1" face="Verdana" id="quote]quote:Originally posted by MärCo I am in very much doubt of your answer. With DC polarity does matter, with AC not. I still think the 18VA adapter is AC. If we are talker purely about the transformers current, I agree with Märco. All physic laws must change for making a DC coil-based transformer But in combination with a Digital like station (e.g. Delta4f, 6021, Mobile/Central station) the current could be considered a 'very dirty' DC like current imho.
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Lars Westerlind		#6 Posted : 08 September 2006 22:06:09(UTC) Retweet
Joined: 19/10/2001(UTC) Posts: 2,379 Location: Lindome, Sweden		Then you both are wrong. The 18 VA is DC, just look at it instead of making such idiotic remarcs. It's printed ot it. It's another story that inside the adapter is a transformer which of course is AC, and then a rectifier giving DC. You may use it for accessories, and polarity doesn't matter as KGS points out. BUT, feeding accessories with DC give some slight differences: 1. They become more silent, as no 50 Hz is present. Significant difference for decoupler track. 2. Remanent magnetism may cause stickiness; again the decoupler track stays up; but only until a car passes and releases the stickiness. 3. The current throuch a coil feels less resistance; might be higher and cause damage. Regards, Lars
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john black		#7 Posted : 08 September 2006 22:37:20(UTC) Retweet
Joined: 22/04/2004(UTC) Posts: 12,139 Location: New York, NY		Quote: [size=1" face="Verdana" id="quote]quote:Originally posted by Lars Westerlind <br />The 18 VA is DC, just look at it instead of making such idiotic remarks. ... BTW, how much did you pay for it, Hal ?
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Hemmerich		#8 Posted : 09 September 2006 00:09:04(UTC) Retweet
Joined: 15/04/2003(UTC) Posts: 2,734 Location: ,		Everything stated by Lars is correct. You can still use this 18VA DC power pack to control switches and uncouplers; as long as you don't activate a switch/uncoupler too freqently.
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Gert-Jan		#9 Posted : 09 September 2006 00:11:51(UTC) Retweet
Joined: 29/04/2005(UTC) Posts: 777 Location: Netherlands		Quote: [size=1" face="Verdana" id="quote]quote:<br />The 18 VA is DC, just look at it instead of making such idiotic remarks. It's printed on it. I stand corrected. [:I] Having DC power for e.g. decoupling rail is very nice to have...less noise and vibes. I still use my old Delta4F with my 6002 transformer to get a same result. So is it correct to say that the new 'Systems' transformers have a AC-DC bridge inside, unlike the old (pre-systems) transforers? After a glance at the 'ugly box' circuitboard, it really gaved me the idea that those diode-bridge was responsible for the AC to DC conversion...or is it something else?
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soren36		#10 Posted : 09 September 2006 00:13:56(UTC) Retweet
Joined: 25/03/2006(UTC) Posts: 858 Location: Connecticut, USA		Lars - thanks for input. Your comment "<u>3. The current throuch a coil feels less resistance; might be higher and cause damage</u>." - damage to what? And John (did I start something?[}:)]) - $22 - a second 60VA was $100+. Since I only want to drive one switch or uncoupler at a time, it seemed like a good idea. Also, I don't know where I will end up - although surely bigger than I originally thought.
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clapcott		#11 Posted : 09 September 2006 00:51:25(UTC) Retweet
Joined: 12/12/2005(UTC) Posts: 2,435 Location: Wellington, New_Zealand		fwiw AC v DC does matter if you include the lighting aspect of some accesories (buffer stop light, turnout indicator lights, signal lights etc.) if these use LEDs, which a number of Marklin items do, then you need to be conscious of polarity
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perz		#12 Posted : 09 September 2006 01:13:28(UTC) Retweet
Joined: 12/01/2002(UTC) Posts: 2,578 Location: Sweden		Quote: [size=1" face="Verdana" id="quote]quote:damage to what? To the accessory. A too high current may burn the coil in it. The power supply is over-current protected and should not be damaged.
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David Dewar		#13 Posted : 09 September 2006 01:47:36(UTC) Retweet
Joined: 01/02/2004(UTC) Posts: 7,343 Location: Scotland		Hal : Just about now you must be wishing you hadnt started the topic. David
		Take care I like Marklin and will defend the worlds greatest model rail manufacturer.
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john black		#14 Posted : 09 September 2006 03:43:07(UTC) Retweet
Joined: 22/04/2004(UTC) Posts: 12,139 Location: New York, NY		Quote: [size=1" face="Verdana" id="quote]quote:Originally posted by soren36 <br />And John (did I start something? [}:)]) - $22 You did, Hal. Big deal for you [:p] - big fun for us
		I hope no one visits a poor Southener's layout in Brooklyn. Intruders beware of Gators. AT&SF, D&RGW, T&P, SP, WP, UP, BN, NYC, ARR, epI-III - analog & digital Marklin Classics only. CU#6021 FX-MOTOROLA DIGITAL SYSTEM. Fast as lightning and no trouble. What else ... Outlaw Member of BIG JUHAN's OUTSIDER CLUB. With the most members, worldwide
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soren36		#15 Posted : 09 September 2006 04:08:31(UTC) Retweet
Joined: 25/03/2006(UTC) Posts: 858 Location: Connecticut, USA		Question now is -withdraw the original question, or post a follow-up? Seriously, I very much appreciate all the input, but remain unclear as to what I should - or shouldn't - do. Are the leads interchangeable? Is there a real danger to my accessories if I use this trafo at all? From the label: Model 66185 STEGER 36-012.2 Input 120V AC 60Hz Output 20.8V DC 18VA Hal
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john black		#16 Posted : 09 September 2006 05:50:53(UTC) Retweet
Joined: 22/04/2004(UTC) Posts: 12,139 Location: New York, NY		Quote: [size=1" face="Verdana" id="quote]quote:Originally posted by Hemmerich <br />as long as you don't activate a switch/uncoupler too frequently ... and since you don't switch the very same turnout 20 times in a row - that's your ticket, Hal BTW, taking no chances re your turnout LED's - the white striped is the hot one ...
		I hope no one visits a poor Southener's layout in Brooklyn. Intruders beware of Gators. AT&SF, D&RGW, T&P, SP, WP, UP, BN, NYC, ARR, epI-III - analog & digital Marklin Classics only. CU#6021 FX-MOTOROLA DIGITAL SYSTEM. Fast as lightning and no trouble. What else ... Outlaw Member of BIG JUHAN's OUTSIDER CLUB. With the most members, worldwide
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xxup		#17 Posted : 09 September 2006 07:40:04(UTC) Retweet
Joined: 15/03/2003(UTC) Posts: 9,473 Location: Australia		I have an even siller question... Is this the same transformer that powers the MS? Does this mean that all of our (digital) locos are now DC??? I am really confused by this posting..
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Lars Westerlind		#18 Posted : 09 September 2006 11:59:07(UTC) Retweet
Joined: 19/10/2001(UTC) Posts: 2,379 Location: Lindome, Sweden		Hal, I would prefer to use an AC source for you accessories; that's what they are built for. Clapcot is right also of course. We have already given the full answer, that it's possible to use a DC source as well, but with slight risks if you don't know what you do. Adrian: yes, it's the same transformer we speak about. But no, there is no correlation. The longer answer is that Mobile Station (and other digital units) has a rectifer which in allows for feeding both AC or DC, inside electronics always work with DC. It then produces a digital signal to the track, which is not DC and not traditiononal (sinus) AC, but a square signale chaning between + and - like AC does. The decoder gets this signal, and in most cases (37xxx locos) produces a pulsed DC signal to the motor, which is a DC-motor. But not always; there exist traditional all current motors (as you certainly know), and special motors as C-sine. /Lars
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hmsfix		#19 Posted : 09 September 2006 13:31:10(UTC) Retweet
Joined: 06/02/2005(UTC) Posts: 1,383 Location: Darmstadt,		Interesting... these 18 VA devices produce DC. Or perhaps we could say they produce a very lazy AC, that alternates very infrequently ? Hans Martin
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perz		#20 Posted : 09 September 2006 14:40:59(UTC) Retweet
Joined: 12/01/2002(UTC) Posts: 2,578 Location: Sweden		The 18 VA device produces nice and stable DC. No visible 50 (60) Hz ripple, at least not with low loads. Quote: [size=1" face="Verdana" id="quote]quote:Or perhaps we could say they produce a very lazy AC, that alternates very infrequently ? The voltage goes up when you turn it on and goes down when you turn it off, but I wouldn't call that "alternate". To really alternate it should give a voltage vith opposite polarity sometimes. That never happens.
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jte		#21 Posted : 09 September 2006 19:42:55(UTC) Retweet
Joined: 30/10/2005(UTC) Posts: 117 Location: ,		Hi all, AC-coils will function also with DC-current, but there is a risk for very high peak voltages due to the inductance when switching on and off. DC-coils usually have a protection diode to eliminate these peak voltages. Especially if some electronics are also in the same circuit, I wouldn't recommend DC-current for AC-coils. Also as Lars earlier wrote, the current is usually higher with DC, because there is only galvanic resistance limiting the current as the inductive resistance is zero for DC. Juha
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soren36		#22 Posted : 10 September 2006 05:30:31(UTC) Retweet
Joined: 25/03/2006(UTC) Posts: 858 Location: Connecticut, USA		Quote: [size=1" face="Verdana" id="quote]quote:Originally posted by David Dewar <br />Hal : Just about now you must be wishing you hadnt started the topic. David David - Good Grief! But I'm certainly learning something - and I think others are as well. Hal
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soren36		#23 Posted : 10 September 2006 05:44:48(UTC) Retweet
Joined: 25/03/2006(UTC) Posts: 858 Location: Connecticut, USA		Given the obvious expertise of Lars, and the backup from Juha - the 18VA DC trafo will be replaced with a proper AC unit. I appreciate the lesson and enjoyed the lively discussion. Thanks to all who joined in. Hal
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Tony		#24 Posted : 10 September 2006 21:06:12(UTC) Retweet
Joined: 18/09/2004(UTC) Posts: 726 Location: Cape Town		Just my 5 cents worth on this. ( think I mentioned this before somewhere?) I would advise not to use DC to operate points/switches/turnouts if you are relying on the end shut off switches (C track)and using a non pulsed supply. (ie not momentary) The little end shut-off switch is not rated to cut off DC and will most probably result in the contacts fusing together resulting in permanetly operating the point "motor" burning it out very quickly!! I use DC for other devices but with care - as Lars has indicated.
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Maxi		#25 Posted : 10 September 2006 21:51:26(UTC) Retweet
Joined: 28/04/2003(UTC) Posts: 757 Location: Wawa, Ontario		Quote: [size=1" face="Verdana" id="quote]quote:Originally posted by Tony <br />Just my 5 cents worth on this. ( think I mentioned this before somewhere?) I would advise not to use DC to operate points/switches/turnouts if you are relying on the end shut off switches (C track)and using a non pulsed supply. (ie not momentary) The little end shut-off switch is not rated to cut off DC and will most probably result in the contacts fusing together resulting in permanetly operating the point "motor" burning it out very quickly!! I use DC for other devices but with care - as Lars has indicated. I use DC on my C-track turnouts and have yet to have a problem. All turnouts are controlled via k83 decoders or manual switches, works every time for me. The key point is to only send a pulse of power to the turnout and not continuous power. Maxi
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Tony		#26 Posted : 12 September 2006 14:24:23(UTC) Retweet
Joined: 18/09/2004(UTC) Posts: 726 Location: Cape Town		Quote: [size=1" face="Verdana" id="quote]quote:Originally posted by Maxi <br /> Quote: [size=1" face="Verdana" id="quote]quote:Originally posted by Tony <br />Just my 5 cents worth on this. ( think I mentioned this before somewhere?) I would advise not to use DC to operate points/switches/turnouts if you are relying on the end shut off switches (C track)and using a non pulsed supply. (ie not momentary) The little end shut-off switch is not rated to cut off DC and will most probably result in the contacts fusing together resulting in permanetly operating the point "motor" burning it out very quickly!! I use DC for other devices but with care - as Lars has indicated. I use DC on my C-track turnouts and have yet to have a problem. All turnouts are controlled via k83 decoders or manual switches, works every time for me. The key point is to only send a pulse of power to the turnout and not continuous power. Maxi Hi Maxi Quite right - I have only had the problem with non pulsed DC supplies to the turnouts. A Non pulsed AC supply is fine and the end cut off switch operates well.
		Regards Tony
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clapcott		#27 Posted : 12 September 2006 23:55:40(UTC) Retweet
Joined: 12/12/2005(UTC) Posts: 2,435 Location: Wellington, New_Zealand		Quote: [size=1" face="Verdana" id="quote]quote:Originally posted by Tony Quite right - I have only had the problem with non pulsed DC supplies to the turnouts. A Non pulsed AC supply is fine and the end cut off switch operates well. I think you need to include a disclaimer as to which turnout motors you are refering to. There are a couple of versions of the 74490, early types (e.g v1.1)only included a cutoff switch at one end.
		Peter
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Tony		#28 Posted : 13 September 2006 09:47:28(UTC) Retweet
Joined: 18/09/2004(UTC) Posts: 726 Location: Cape Town		Quote: [size=1" face="Verdana" id="quote]quote:Originally posted by clapcott <br /> Quote: [size=1" face="Verdana" id="quote]quote:Originally posted by Tony Quite right - I have only had the problem with non pulsed DC supplies to the turnouts. A Non pulsed AC supply is fine and the end cut off switch operates well. I think you need to include a disclaimer as to which turnout motors you are refering to. There are a couple of versions of the 74490, early types (e.g v1.1)only included a cutoff switch at one end. Thanks Peter - yes I am referring to the more recent version of the 74490 - All mine bought over past 2-3 years and they seem to be fine with cutoff switches both ends.
		Regards Tony
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stenscience		#29 Posted : 14 September 2006 00:39:43(UTC) Retweet
Joined: 18/09/2004(UTC) Posts: 789 Location: Santa Fe, New Mexico		[|)][|)][|)]arghhhhh! My head hurts. I am going to operate all my turnouts by hand after this
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David Dewar		#30 Posted : 14 September 2006 01:16:34(UTC) Retweet
Joined: 01/02/2004(UTC) Posts: 7,343 Location: Scotland		I know what you mean George...but Hal is now buying a new transformer which seems a good idea although I dont think anybody suggested it. No need for an expensive one though !! David
		Take care I like Marklin and will defend the worlds greatest model rail manufacturer.
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hmsfix		#31 Posted : 14 September 2006 02:13:52(UTC) Retweet
Joined: 06/02/2005(UTC) Posts: 1,383 Location: Darmstadt,		Hi, Did some test tonight as follows: I connected a 7245 universal relay and a 7549 turnout magnet to 16 volts, AC and DC. and observed the currents. I was a little surprised about the result: 7245: AC: 0.4 A (and 0.3 A when it has got hot) DC: 0.8 A (and 0.7 A or so in hot state) 7549 (I blocked the mechanism, so end switches could not interupt the current): AC: 1.0 A (getting very hot within seconds) DC: 1.4 A (guess!) Both devices are getting very hot if the current is allowed to flow continuously and may be fried within 10 seconds. That's a very short period, isn't it ? The current is higher than for any loco, allthough it is only needed for a fraction of a second: even a 32 VA trafo is exhausted with two turnout magnets triggered at the same time. For the turnout magnet, there is no temperature problem if the end switches work properly. Couldn't even find any difference between AC and DC. With DC it seems to switch a little faster, so it does not produce more heat. Another lesson: If you want to power a turnout magnet by a transistor device, spend that 10 cts more to get an output transistor rated for 2 A. Hans Martin
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Lars Westerlind		#32 Posted : 14 September 2006 09:47:44(UTC) Retweet
Joined: 19/10/2001(UTC) Posts: 2,379 Location: Lindome, Sweden		Thank's for sharing. It's always good to see theoretcial expectations come through; that we weren't lying. You have not measured on the new ones? My impression is that C-track turnouts draw less current, and an old 7045 might even draw more? In the old times (my youth) I think the major idea was to allow for large currents, with significatn voltage drops. Still I would guess that those magnects could take a lot of heats. I've certainly been standing a contact tracks for more than 10 s, without ever frying any turnout motors... /Lars
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Lars Westerlind		#33 Posted : 14 September 2006 09:49:06(UTC) Retweet
Joined: 19/10/2001(UTC) Posts: 2,379 Location: Lindome, Sweden		BTW, shouldn't the topic be changed to 'interesting question', or possibly 'silly answers' :-)
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hxmiesa		#34 Posted : 14 September 2006 11:30:01(UTC) Retweet
Joined: 15/12/2005(UTC) Posts: 3,520 Location: Spain		Hi guys, I would like to supply muy experiences too. I use 24Vdc for my switch-motors. (K and M track) From a PLC I change up to 2 switches at the time. The PLC is programmed to give 2 pulses of 0,5 second duration, with a 0,1 second pause between them. This was found necessary to overwin any mechanical resistance, and to ensure perfect operation every time. I tried first with the normal 16Vac, and that was as a disaster! The end cut-off contacts in the K-motors are not modified (yet). I understand that if you use digital and STANDARD Märklin components to operate the switch-motors, you are actually using 18V, but not pure DC or AC, but the digital signal, which is rather different. (it´s more like DC than AC, I think?!)
		Best regards Henrik Hoexbroe ("The Dane In Spain") http://hoexbroe.tripod.com
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Lars Westerlind		#35 Posted : 14 September 2006 11:52:48(UTC) Retweet
Joined: 19/10/2001(UTC) Posts: 2,379 Location: Lindome, Sweden		No, standard k83s have a capacitator inside which gives a pulse, which much like negative exponential. The reload current is taken from the digital source, half wawe rectified, so yes, after a while there will be a significant "ripple", but not strong enough to burn anything. /Lars
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hmsfix		#36 Posted : 14 September 2006 12:55:30(UTC) Retweet
Joined: 06/02/2005(UTC) Posts: 1,383 Location: Darmstadt,		Quote: [size=1" face="Verdana" id="quote]quote:Originally posted by Lars Westerlind <br /> You have not measured on the new ones? My impression is that C-track turnouts draw less current, and an old 7045 might even draw more? In the old times (my youth) I think the major idea was to allow for large currents, with significatn voltage drops. [/br] Hi Lars, I have somewhere a 7045 running here. Must get through the wire jungle under my layout and check that... Quote: [size=1" face="Verdana" id="quote]quote: <br /> Still I would guess that those magnects could take a lot of heats. I've certainly been standing a contact tracks for more than 10 s, without ever frying any turnout motors... [/br] Well, I had my finger on the 7549 magnet coil when I tested it, and it got incomfortably warm after few seconds. If not the coil so at leased my finger would have been fried after 10 s, I suppose. BTW my old M track turnouts withstand much longer periods without getting too warm, maybe hours. Hans Martin
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john black		#37 Posted : 14 September 2006 15:59:35(UTC) Retweet
Joined: 22/04/2004(UTC) Posts: 12,139 Location: New York, NY		Quote: [size=1" face="Verdana" id="quote]quote:Originally posted by hmsfix <br />my old M track turnouts withstand much longer periods without getting too warm, maybe hours One can say what he wants - old time stuff is still best [^]
		I hope no one visits a poor Southener's layout in Brooklyn. Intruders beware of Gators. AT&SF, D&RGW, T&P, SP, WP, UP, BN, NYC, ARR, epI-III - analog & digital Marklin Classics only. CU#6021 FX-MOTOROLA DIGITAL SYSTEM. Fast as lightning and no trouble. What else ... Outlaw Member of BIG JUHAN's OUTSIDER CLUB. With the most members, worldwide
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