O22 Switch Contacts Burning Out?

[Neil Poersch]

Hi everyone,

Has anyone had a similar problem with burning out the sliding electrical contact strips inside the O22 track switch?

I have eight new Lionel O22 switches that I have bought at various times within the past year. One switch was starting to operate only intermittently.  I opened it up this weekend suspecting a broken wire or such. Instead I found that the electrical contact strips on the circuit board are being eroded away by the sparking of the mating contact point that moves when the track changes position. This has resulted in a literal trough in the contact strip where the metal has been eroded away (visualize an arc welder melting away metal and you get the picture).

Now to make things worse I checked two of the other seven switches and they were beginning to show evidence of spark erosion on the contact strips also. These switches were not as bad as the first one as the first switch is the one which operates the most frequently on my layout. I suspect that all of these switches will have the same trouble.

I should mention that this layout does not get a lot of use. I have it set up mainly for my two young grandsons to use when they come to stay with us for a long weekend.

The siwtches are connected to the Fixed Voltage 'D' terminal of my 1950's era KW transformer. The output voltage at this terminal is about 18 VAC.

I have referred this to my local dealer who will contact Lionel on my behalf. However it seems apparent to me that this is a design flaw. The thickness of the metal contact strip is clearly not capable of handling the high current load caused by operating the solenoids inside the O22 switch.

I don't think that I am doing anything abnormal here ( in fact I have two 1950's era O22 switches which are fine) so I was wondering if anyone had similar experiences.

Any comments would be welcome.

Thanks,

Neil

[Roger Bielen]

If you can, try going down to 12 to 16 volts.

[steinmike]

Neil:

I assume that when you say "new" that you're referring to the 6-14062 and 6-14063 O31 swtiches.  I also have them on the layout (and also using a KW for switch power, but from the "B" throttle set for 14VAC) with some of the infamous 612-3010/3011's and have not encountered any problems with the contacts.

I checked the owner's manual for the 14062 and the 14063 and could not find any cautions with regard to voltage.  The owner's manual for the 612-3010/3011 does have a warning: "IMPORTANT: Do not continuously apply more than 14 volts alternating or direct current to the switch (either via track power or through the auxilliary power terminal) or your switch may be damaged..."

You might want to speak with someone in tech support at Lionel to see if 18VAC is a problem.

Good luck,

Mike

[lionel2]

I have 6 pairs of 022 remote switches...12 total...i was always told to buy them mint/OB...so thats what i did...i paid roughly 50 to 55 each for my pairs....mint with everything and original boxes....they are hard to repair and i did not have a welder or anything like that...as for repairing...ond of the clasic toy trains magazines tells you how to repair them...thanks

[phillyreading]

Sounds like warrenty time!   It sounds like Lionel is having problems again with switches!

I have some older 1994 Lionel 6-23010 switches and the switch motors went crazy on me! When a certain locomotive got within three track sections of the switch the motor in the switch starting throwing the direction piece back & forth about 45 times a second, also a few years later the switch would lose power completely.

I have tried contacting Lionel with NO results! 

I know that Lionel switches in O gauge would look nice but have you considered using MTH or K-Line switches? 

Lee F.

[Neil Poersch]

Thanks everyone for your responses so far.

Yes, the switches are the O31 6-14062 and 6-14063 units.

I am using the other variable output of the KW for operating a trolley car so it is not available for the track switches.

I really don't think that the problem is using 18VAC instead of 12 VAC. The issue is that the current drawn by the unit's solenoid is being interrupted by the normal operation of the track switch which causes a spark. The foil trace on the circuit board is not thick enough to take the heat from the current spark and the foil is being disintegrated. I don't think that reducing the voltage would affect this.

I will let you know what Lionel comes back with for warranty support.

Neil

[lionelsoni]

The coil is a linear device; so we can expect the coil current to be proportional to the coil voltage.  Whether the turnout should be so vulnerable to arcing that a modest change in voltage even comes close to making a difference is another question.

[steinmike]

Neil:

Please let us know what you hear from Lionel on this matter.  Since the instruction manual doesn't caution against the use of higher voltages, they shouldn't give you any grief on that issue.

Bob:

I agree with you that the difference in operating voltage from 14VAC to 18VAC (4VAC) doesn't seem significant and you would think that a device like a switch should be able to handle a 28% overload, but then why did Lionel put the warning in for the older model 3010/3011 switches?  Most of my problems with the 3010/3011 switches went away when I went to an SC-2 TMCC switch controller and disconnected the manual switch controllers.  Could the pitting on the contacts result from the controller being closed (and the contacts energized) for a longer period than expected?

Regards all,

Mike 

[Mark K]

I had the same problem with the only modern (an 0-72 purchased in 1999)switch on my layout. It happened after about a year of operation. I ended up replacing the switch motor with a postwar motor. This completely solved the problem but was not easy to do. I had to do a bit of modifying to get it to fit. I was really disappointed in the quality of the modern switch motor as compared to the postwar unit. With a $99.00 list price I would have hoped for better. I have not had any problems with the postwar switches in the 8 plus years my layout has been together.

Mark

[Neil Poersch]

Hi again everyone,

A few comments.......

Bob, you are right of course, the solenoid coil is linear so the current drawn by the coil will decrease as the fixed voltage supply is reduced.  However I think that the problem is not related to the steady state current but rather is related to when the coil is switched in or out of the circuit. An arc is generated at that time by the collapsing of the magnetic field of the solenoid. This energy has nowhere to go so it jumps as an arc between the contacts. The root cause of this problem, in my opinion, is that one half of the contact is only a very thin metal foil similar to that found on a printed circuit board, maybe a few thousandths of an inch thick. The contacts on my 1950's era switches are separate metal strips which are probably 50 or 60 thou thick and much more able to handle the heat of the current flow. The old strips almost appear to be silver plated also........don't know if that's true or not but sure looks like it.

The solution is to have heavier metal contact strips on the new switches.  Even if Lionel stands behind their products and repairs or replaces my switches  I suspect I will still end up with the light metal contact strips which means the problem will re-occur sometime in the future.

An mitigating strategy would be to install a metal oxide varistor across the terminals of the solenoid coils to absorb the arc. I will probably do this if the repaied switches still have the light foil.

So, yes, reducing the fixed voltage from 18VAC to 12-14 VAC would probably help but it won't solve the problem.

For the record, I checked all eight of my new Lionel track switches and they all showed evidence of erosion of the contact foil strips. The degree of erosion was proportional to the amount of switching traffic on each individual switch.  Obviously a design problem here. What is interesting to me is that many other folks should be having this same problem. I can't see that my situation is all that unique.

Neil

[lionelsoni]

While you've still got some foil left, you might try reflow-soldering or even gluing suitably thin brass strips over the foil.

[Birds]

Neil,

I'd be interested in seeing some pictures of what you are talking about.  Any chance of taking a digital photo and posting it on the thread?

I have purchased four O22 switches in the past 13 months and have had them in use.  I run them at 14 volts using the constant voltage plugs on the side.  None of them show signs of the foil contact plates being eaten or scratched through.

There are some slide marks on the foil contact plates.  I have looked at them using a magnifying glass and still don't see anything that alarms me or seems beyond normal wear and tear.

The contacts and plates on my switches still have quite a bit of lubricant on them.  Some of the lubricant is dirty and black, but when you spread it around the contact plates don't show any etching that I can see (even with a magnifying glass).

A few of my switches have been setup for automatic switching with two trains running, and I did it incorrectly.  This resulted in one or two of them "chattering" a lot as the solenoid went nuts.  Those switches don't show anything different than the ones that didn't "chatter". 

I also checked a couple of my switches from the early 1990's (the ones everyone complains about).  I also run those at 14 volts and have had no problems.  Their plates are thicker and have no lubricant.  They show darker slide marks, but again nothing is etched into the contact plate.

Chris

[Neil Poersch]

Hi Chris,

Thanks for your note. It was exactly the info that I was hoping to get from another user of these switches.

Two obvious differences between your and my operation. I was running my switches on the fixed voltage terminal of my KW which is 18 VAC vs your 14VAC.   Also I had all of my switches set up for automatic switching so that a train running on my layout went through at least six of the switches on one traverse of the layout and each of those switches would operate at least one if not twice on a single traverse. So I had lots of switching action going on.

Interesting that you show no evidence of the contact strips eroding.  I will try to take a digital picture this weekend to post to this thread. The worst unit is with my dealer but some of the others have significant erosion so it should show up OK.

Neil

[Birds]

Neil,

Please post what the dealer comes back to you with. 

I just took delivery of a number of brand new O22 model switches yesterday and found some big differences in the manuals included with these compared to the manuals included with the switches I purchased 12-13 months ago.

The brand new manuals don't say anything about voltage ranges.

The manuals from 12-13 months ago specifically state to "Connect your O22 switch to a power supply that provides a steady 9 to 14 volts of power.  Operating your switch from track power in the Command Control environment may cause permanent damage to your switch."

My understanding is that with Command Control one is running the power between 18-21 volts.  So there was that caution in the past year about running the switches at high voltages.  Why that comment isn't included in the new manuals is another question.

I was orginially powering my O22 switches off of the fixed voltage posts of a KW, but 12 volts was too sluggish, and I felt 20 volts was too much power.  So I have been powering them from a small starter set transformer.  I use a volt meter to see when the voltage is at 14 volts.

I feed the constant voltage posts with 16 gauge wire that have spade connectors crimped on the ends.  These receive power from a terminal strip attached to the small transformer.  The power to the switches are home run (or star) wired.

As a side note...

Isn't there something called "inductive load" with switches?  I don't understand all that as well as others, but maybe 18 volts is high enough to produce an inductive load that is too much for these plates with constant use over time?

A four volt variance with many modern electronics will fry the device.  Maybe toy train production has finally gotten to the point where the products are designed with a finer tolerance in terms of voltage ranges?

Chris

[lionelsoni]

A resistor has a voltage across it that is proportional to the current flowing through it--Ohm's law.  An inductor has a voltage across it that is proportional to the rate of change of the current flowing through it.  So, when you open an inductive circuit, the rate of change of current is infinite--it stops immediately.  This creates an infinite voltage across the inductor.  In practice, an arc forms before the voltage can get to infinity and lasts until the current goes to zero.

The coil in a turnout is equivalent to an inductor in series with a resistor (the wire resistance of the coil).  That is why the contacts arc when you shut off the coil.

If your small transformer is a simple sine-wave transformer, your voltmeter is telling you the actual voltage.  If it is something like a CW80 or "Powermax", the actual voltage can be quite a bit different from what the voltmeter reads.

[Neil Poersch]

Chris,

I will post what the dealer/distributor comes back with for my switches.

By the way my switches did not come with any type of manual.

In my earlier post I speculated that the burning of the contacts was caused by the arc resulting from the inductive load of the solenoids. I still think that if the new switches only have a thin metal foil for a contact then something such as a varistor has to be added across the coil to suppress the arc.

Neil

[lionelsoni]

I agree, Neil.  Even the RC networks once used for telephone relays would be a big help.

[Birds]

This discussion comes at a good time for me.

I have eleven O22 switches that I am going to install into a permanent layout in the next couple weeks.

The suggestion of a varistor is something I am willing to look at installing since half my switches are brand new and everything else is currently in good shape and easy to access.

1. What size or rating varistor would you all recommend?
2. Would a MOV be the correct choice?
3. Where would you install it? 

Here is a drawing and some photos of a solenoid and contact plate from an O22 switch.  Descriptions for each photo are above the photo.  I tried to get everything in the photos.

Here I labeled the leads on the solenoid to make discussing them easier. 

 

• In the photo below the solenoid leads start as the left and would be "A", "B", "C", and "D".
• The yellow wire runs from a binding post and goes directly to a contact plate with a slide.
• The blue wire on solenoid lead "A" runs directly to a contact plate with a slide.
• The brown wire on solenoid lead "B" runs directly to a contact plate with no slide.
• The red wire on solenoid lead "C" runs directly to the switch's lamp.
• The red wire on solenoid contact "D" is routed over the solenoid to the other side (see photo below) and then runs to a contact plate with a slide.

  

• This is the opposite side of the solenoid.
• The brown wire comes from the switch binding post and runs directly to a contact plate with a slide.
• The red wire on this side runs over the top of the solenoid and appears to connect to solenoid lead "D" (shown in the photo above).  This red wire then runs to a contact plate with a slide

 

• These are the contact plates

 

 

Thanks for the discussion.

Chris 

 

[lionelsoni]

You could use an MOV, but I think a TVS would give you a sharper voltage limit.  The voltage rating needs to be at least 1.4 times the greatest RMS voltage you are going to use.  There's not much energy involved, so a 500-watt device should be big enough.  How about a Vishay SA30CA?

I would put the device in parallel with the coil; but it would probably be effective also across the contact.

[Birds]

Bob,

Found the Vishay SA30CA at Mouser.  I have to order a lot of toggle switches from them so this is good timing.

A couple more questions:

The VBR on the SA30CA is 28.5v min and 31.5 v max.

• If I am running the switches at 14 volts, would the SA15CA (with a VBR of 16.7 v min and 18.5 v max, and a VRWM of 15 volts), keep the supressed voltage closer to 14 v and provide more protection?  The IRSM is 20.5 and the VRSM is 24.4.

I was also looking at the SA13CA, but figured the VRWM of 13 volts might be a problem if I want to run the switches at 14 volts.   

• When you mention to install the device "in parallel", do you mean to install one end on lead "A" and the other end on lead "D" (see the drawing I posted above)?

• Are the TVS directional, needing to be installed a certain way?

Thanks,

Chris 

[lionelsoni]

Remember that the RMS voltage (your 14 volts) actually goes to a peak of 20 volts every half cycle.  That's why you need to multiply the RMS value that you plan to use by 1.4 before selecting the TVS.  The SA30CA would therefore be suitable for up to about 20 volts RMS.  So you could go lower on the voltage rating if you are very confident that you won't ever raise the voltage; but keep it at 20 or above for 14 volts RMS.

You need two of these for each turnout, one for each coil.  Connect one to A and B, the other to C and D.

The CA suffix means bidirectional, which is what you need for AC voltage.  So you can install it either way.

[Birds]

Bob,

Thank you for pointing out that the solenoid is actually two coils.  I had been looking at those four leads and it just didn't register that it was two coils.

I am bit confused about the RMS multiplied by 1.4, and the choice of an SA30CA TVS.

I understand that the TVS needs to be sized at RMS x 1.4.

For the RMS used in the calculation, does one use the voltage setting for the switch (14v), or the peak of every half cycle (20v)? 

As I do my calculations I keep arriving at the SA30CA being 10v more than needed if I use 14v in the calculation, but I get 28v if I use the peak of 20v from every half cycle.

Here is what I am doing:

• Switch voltage: 14v RMS (powered by a KW, and measured with a digital VOM.  It is my understanding that a DVOM reports volts using the RMS calculations.)
• Peak voltage (VRWM): 14 x 1.4 = 19.6 v (round up to 20 volts)
• TVS sizing: VRWM = 20 volts
  

According to Mouser's PDF:

• SA30CA: VRWM = 30v
• SA20CA: VRWM = 20v

To me it would appear that the SA20CA would work for a switch powered by 14v RMS.

Thank you for your time and patience.

Chris 

[lionelsoni]

"So you could go lower on the voltage rating if you are very confident that you won't ever raise the voltage; but keep it at 20 or above for 14 volts RMS."  What I meant here was that you could use a rating of 20 volts, that is, an SA20CA, if you never go above 14 volts RMS, which seems to be what you understand as well.

"The SA30CA would therefore be suitable for up to about 20 volts RMS."  This was based on using the 30-volt rating of the SA30CA for the peak voltage of 28 volts that goes with 20 volts RMS.

I think that, because I was describing two different situations in my posting that you may have gotten the idea that I was multiplying by 1.4 twice:  14 * 1.4 = 20, then 20 * 1.4 = 28.  But they're really two different examples.  The reason I mentioned the 20-volt RMS example was to suggest that you might want to think carefully about whether you will always want to use no more than 14 volts before locking yourself into that voltage.

[Birds]

Bob,

Thank you!

I understand what you are saying.  I didn't catch that you were providing examples for two different voltages - 14v and 20v.

Thank you very much!

Chris 

[msacco]

Thanks Neil for this one!

I'm bringing this thread to the top for good reason. After reading Neil's initial posting I happen to check 1 of my 3 new 022 switches because it was getting stuck a bit. I unscrewed it from my layout which I will be ballasting in a few months. OPened up the switch motor and found eroded contacts in two of the 4 contacts. Eroded like a trough right down to the plastic base below.

     This is really bad. Lionel needs to hear about and I'll draft them a letter. If you have these switches I seriously think you should check them out. I run them at 15 volts and this should not be happening. Thankfully I can rip these out because I haven't sceniced yet.

    Thanks again Neil, as I am now refurbishing some of my 022 postwars and will put them down and of course these Amercian made switches will go another 50 years.

MIke S.

[Neil Poersch]

Hi Mike,

Sounds like your experience is identical to mine. I intend to post a picture of the contacts as soon as I can figure out how to do it. The contacts are exactly as you describe......a trough eroded in the middle of the contact.

Good to hear that you were operating at 15V. I really didn't think that my operation at 18V was the real cause of the problem.

So far only silence from Lionel...but it's only been a week since I complained to my local dealer (who is being very supportive)

Neil

[msacco]

Neil,

thanks again really!!!!. I will be ballasting in a month or two and I would have been really ticked off down the road if there had been a problem with these switches.

    I have already ripped these overseas switches out of my layout and installed postwar 022s.

I have one with no damage yet out of three and maybe I'll just keep it for christmas tree layouts and such. I'm getting tired of the cheapness of this new garbage they're selling.

 

Mike S.

[Neil Poersch]

 

Iam trying to upload a picture of the burned contacts. Lets see if this works.......

Neil

http://i179.photobucket.com/albums/w285/npoersch/SwitchContactsNeil002.jpg[/img]

[msacco]

Neil, don't see the pix but maybe I'll try to shoot one as well. As I packed these new 022s away I glanced at the manual and it say 14 volts max. Well I was 1 volt over and I still think they should be able to handle it. I do run postwar 022s with these so I needed some more volts for an extra kick.

  Mike S.

[Birds]

Neil,

You forgot the ["IMG"] (without the quotes) at the start.  Here you go: