I am considering a Kato turntable for a layout I am designing. I understand that the turntable is "power-routing" so that it will feed the stub tracks. But, that confuses me with respect to how it matches power with the entry track(s). Maybe somebody here can help me understand it? If the table got power from the stubs and entry tracks and disconnected power while rotating, that would make sense to me, but I think I have read that it is the other way around. My confusion over a single entry track comes from not knowing what happens if an engine enters the turntable, gets rotated 180 degrees, and tries to leave by the same track it came in on. Unless the power reverses on the table, wouldn't the engine wheels cause a short when they bridge the table and entry rails? More confusing, I am considering a layout with 2 enrty tracks to the table. How do I wire things so that one or the other path does not cause a short when the engine comes in by the one entry and is rotated in whatever way is unpropitious to exit by the other? Steve
I was going to shoot off my theory, and realized there are several issues I hadn't considered. Some turntables feed the table track from a semicircularly divided "slip ring" so they change polarity depending on direction turned, just like picking a DC loco up off the track by hand, turning it around and setting back and track. It goes same track direction, rather than direction of "front" and "back" of loco. But then I think some turntables pick up table track power from two contacts that are in line with axis of rotation, so polarity is NOT changed automatically. Hopefully somebody knows more about specific TT you are using...
There are some pretty good diagrams in the manual which demonstrate how it all works. Also, everything depends on whether you are DC or DCC on what is required. Starting on Page 8, they show a set up with multi entry tracks The key is that you do need to isolate the entry tracks from the rest of your layout; they can reverse polarity (see diagram at top of page 6) depending on the position of the bridge. For DCC, one might want to feed the power for the whole turntable area through an autoreverser, so that any unit crossing into the area automatically adjusts. For DC, you need to use the turntable throttle, and adjust direction accordingly for crossing the boundaries.
Thanks Rick, I found the manual on-line and printed it. I'll read it tonight and figure it out. Steve
I run DCC and used a MRC Auto-reverse unit with my Kato turntable. No problems so far. Pretty slick unit. John
Steve, I have the turntable and am using it on a test loop. The power to the bridge is set in the off position by the operator before she or he rotates the bridge. The user turns the power on to move the locomotive off the table into the roundhouse or lead track. Or if the locomotive is already in the roundhouse, it can be moved onto the bridge, rotated and moved to another stall or to the lead to the mainline. The power unit has two options for "ON". One must chose the correct option based on the end of the bridge the locomotive is moving toward. I have made mistakes in my choice a few times; I am using an NCE Power Cab. When the incorrect power "ON" option is selected; the display goes blank. I simply turn the power "ON" to the alternate position and the display is active. I also have to lead tracks the turn table. If I route the "switch"/track power so a locomotive can move in or out of the turntable area; the turntable power "ON" is left in the off or center position. Once the "switch"/track power is directed back to the mainline, any movement of the locomotive requires the bridge be aligned with the lead where the locomotive is. Kato also has additional leads for activating other track that are attached to the turntable. I am NOT using. I also do NOT have an auto reverser.
OK, I read the Kato instructions. They are oriented towards DC operation, and address the potential for short-circuit alignments with direction switches on the turntable console as well as the regular power throttle, plus a protocol for treating the end of the turntable with the model of the control house as the "entry" end. There seems to be a realization that this will probably cause accidental short-ciruits, because there is a procedure for shutting-down and powering-up the system when shorts occur. I am contemplating using a Kato turntable with an NCE Power Cab, and the instructions don't address that other than to say that the user can plug a DCC system in instead of the usual Kato throttle unit. So I am glad to see that Roger has a Kato turntable and an NCE throttle already in-service. Roger, my thinking after reading the instructions is that there may be a better way to hook-up the electrical feeds when using DCC. Since the engine direction control with DCC does not rely on reversing track polarity, I would like to dispense with those direction control switches to completely avoid potential short-circuit configurations. It seems to me that the turntable power-routing feature could be used in reverse to do that. By feeding each turntable-serviced track directly but NOT the turntable, wouldn't the turntable then be powered from whatever track it is aligned with? The only care would be to set it up with any straight-through situations so that the tracks on both sides of the turntable do not swap white and blue leads as an engine goes straight across. By not feeding DCC power to the Kato turntable contoller, the turntable controller direction switch is not functional and cannot lead to an accidental short-circuit configuration. And, engines could be moved in and out of a roundhouse without first aligning the turntable with their particular track. The only question left in my mind is whether the turntable makes electrical connections with tracks as it swings by each one, or only when it is stopped and the "centering" process is completed. If the former, then I see no reason for any on-off switches to the parking tracks, and maybe still don't see the need for those switches even if the parking tracks get cycled on-off as the turntable swings by. Roger, can you answer that question with your existing equipment and set-up? Additional thoughts, anyone? Steve
Steve, For DCC, it is indeed easier, but not as you posit. Just isolate the entrance tracks, as shown, and feed the turntable through an autoreverser (such as an AR-1 or PSXAR). You can even isolate (via insulated unijoiners) all the tracks coming off the turntable, and wire them normally, with just the bridge being fed from the auto-reverser. The issue, as you state in your original post, is that the bridge does not automatically switch, so that a 180 degree rotation causes a polarity reversal (rail-to-rail).
Rick, Unless there is something wrong with what I suggested, it seems easier than feeding the turntable through an auto-reverser. Just don't feed the turntable at all. Let that aligned track(s) feed it with the power-routing feature. working in reverse of what Kato had in mind. Steve
Steve, I can tell you my experience of simply connecting the NCE Power Cab to the Kato turntable controller. The NCE Power Cab is also connected to the mainline track. It does not need to be complicated. It works for me as I have explained. No auto reverser. When the power knob of the controller is in the OFF position, the power to the bridge is off. Power to the bridge is supplied only when that knob is turned to < or to >. A locomotive can be moved off the bridge into the roundhouse or out of the roundhouse onto the bridge when the power to the bridge is ON. When the bridge is rotated, I leave the controller is in the OFF position. Thus no power is being sent to any track as the bridge turns. I purchased the turntable as soon as it became available in the US and have been using it with a test loop since that time. I had two lead tracks from the mainline to the turntable. I am not trying to advise anyone how to wire this turntable. I am simply explain what worked for me. It was a very simple approach. Steve, I did NOT attempt to connect power to any of the tracks leading into the roundhouse. I cannot address how that would work. I did not seem necessary to me. The turntable controller already takes care of routing power where one wishes to move the locomotive on the bridge. I run steam locomotives and have four of the three-stall roundhouse units.
Has anyone looked at controlling the turntable rotation with DCC? Assuming you could use a programmable stationary decoder to do what the Kato control box does. My only hesitation is cracking the seals on the controller box to reverse engineer the connections. Anyone else tried this? For track power, I isolated the turntable bridge and power this using a OG-AR. All the other tracks have feeders, this allows lights, sound, etc. to continue to function separately from the turntable orientation. There is a good video on YouTube showing this in operation. https://www.youtube.com/watch?v=_xsDt7lvO-8 cheers.
It is not clear to me why one would wish to control the turntable rotation with DCC when it works exceptionally with the power control provided. Also why go to the extra expense? The test loop with the turn table that I set up was based on a Kato track plan and as I recall it was very similar to an operating layout Kato has shown in a YouTube video. Personally I like to keep the electronics of my layout as simple as possible. Good luck with finding a reliable method of operating the rotation as you outlined.
With DCC for TRAIN control, there seems to be two fairly simple approaches for wiring the tracks and turntable. Kato's method is derived from the DC world and its need for reversing switches. When simplified to the DC world, it requires only an autoreverser in the feed to the turntable, which then powers the stubs and maybe isolated sections of the approach tracks, autoreversing when needed during alignments with approach tracks. The postive side of this is that no power leads are required to the stub tracks and it is not possible to drive a locomotive into the pit when the table is not aligned to a track. The down-side is that it is not possible to have the locomotive move in/out of a roundhouse, or use sound and lights unless the turntable is aligned to its track. The other method is to NOT feed the turntable, but feed all of the tracks it can align with, both stubs and approach tracks. That way, the track the turntable aligns with is powering the turntable, and no autoreverser is needed. It is only important to make sure that any tracks directly across the table from each other are powered the same way across the bridge. So, it is possible to drive a loco into the pit when the bridge is not aligned to its track, but it is also possible to fully control the functions of locos on the stubs without aligning the turntable. Individual power switches on each stub track and isolated sections of each approach track could help prevent driving a loco into the pit, but that adds complexity to both installation and operation. Still, with Kato's method, you can drive a loco into the pit from the approach tracks unless you provide isolated sections and switches for each approach. You are just less likely to do that than to accidentally address a loco in the roundhouse and drive it into the pit while looking elsewhere at the loco you INTENDED to move. Steve
I was able to successfully run the turntable rotation with the Kato controller provided and use NCE Power Cab for the dcc source for the track without using an auto reverser. As long as the Kato controller switch for power to the track is left OFF and then turn ON when the rotation is complete, it worked fine for me. I use past tense because I have now packed the turntable in preparation for a move. This is a very simple approach and I believe others have used it successfully.
I have my turntable lead and holding tracks wired to the same circuit with SPST switches to each track. The turntable itself is wired in series with that circuit through a momentary push button. To go from the lead to the holding track, switch the lead in the direction to enter the turntable, and hold the push button until it's fully on the bridge, then release. Then if either the loco is being reversed, or if the turntable is rotated more than 180 degree, reverse throttle polarity, and hold in the pushbutton again to enter the holding track, then shutoff the SPST to that track and it's parked. Pretty simple. I'll have to see if I have a wiring diagram I can post.
Since the bridge takes it’s power from the aligned tracks (stub and approach) there is no need to even connect the Kato track power wire (the bridge rotation is powered through the flat connector) … by powering all the stub tracks the entire operation is now controlled via the DCC throttle and the turntable direction switch. Meaning that the turntable can be DCC by simply connecting power to the stub tracks ( the approach track is obviously bus powered already) and you can do away with the expense of the reverser.
With reference to the original question of two entrance tracks ........ the above still applies since the bridge will pick up power from which ever one is aligned ... no reverser needed!
If two leads from the main line are connected to the turn table, power routed from the mainline will allow a locomotive to move to the bridge when the turnout is aligned. When the turnout is thrown for mainline traffic, no power is going to the bridge. There is one lead from the controller that comes with the turn table and when the Kato turn table controller is set to ON and the bridge aligned with that powered track, the locomotive will move.
