I have a problem with my HO scale turntable. I instaleed it according to the directions and follwed the wirng diagram exactly as it says. I used the Atlas 210 Twin to control the turntable. My Layout is DC controled
My problem is when an engine is on the turntable and I turn on the turntable the locomotive begins moving off of the turntable. The locomotive than proceeds to crash as the truntable continues to move.
The only way this could happen is if you have the track powered other than through the Twin. The diagram shows the power pack going to the Twin, then one switch of the Twin connected to the rails and the other side connected to the two terminals on the motor housing of the turntable. Plus a set of jumpers from the track to the track terminals on the turntable, which are the screws on the table on either side of the motor housing. Wired as shown in the instructions, if you set the left hand side of the Twin to off and turn on the right side, only the turntable will spin, the trains will not move. Once at the desired stall, turn off the right side switch and turn the left one back on, and now the train will move.
In reply to your question…the simple only way to solve Your problem is to use a separate power supply for the turntable drive. Unfortunately the #210 is a DPDT switch which will always be powered…if the switch was a DPDT Center off for both devices then it would work perfect. You can add a SPST switch to one of each output wires, one for turntable bridge power and one for turntable motor power, but that requires more wiring. Simple with just a separate power supply for the motor. Or use it manually with the crank.
I used to own that turntable but sold it a long time ago. I used 215 cab selectors for my blocks and never had any problems becuase I could turn off any track. Here is a wiring diogram I found that might help you. It sounds like you wired your switch wrong. Using this wiring the power is either sent to the motor or the track, not both.
Frank - the diagram with the Twin is shown in the very Atlas instruction sheet you linked and would work fine - if the wires are all hooked up properly. The Twin is a pair of DPST switches. As shown in the instruction, the one on the left turns power on and off to the track - ALL track, and the one on the right turns power on and off to the turntable motor.
It has always been My understanding that the Twin was a pair of DPDT switches used for reversing polarity and it says that on the diagram, that the left is used to reverse polarity on the bridge for loco and the right to reverse direction of the motor for the turntable, there is no off position. The Atlas connector is three parallel DPST switches that can be turned on/off. If they were DPDT center-off switches then it would work perfect using the variable DC output of the transformer. I’ll stand corrected…if I am wrong, but I don’t believe so. Havn’t used Atlas components since the 50’s.
Hmm, so it is. Don’t see why they then suggest that in the manual as a way of both reversing and turning off the power. But it’s right there. I only ever used Selectors and Connectors back in the day, maybe there’s a center off position. A Selector would work, those are DPST. Atlas has some 'splaining to do about their instruction sheet.
The twin is a center off DPDT. It will work just fine provided it is hooked up according to the instructions (worth a double check to ensure nothing got mixed up). One switch is wired to the tracks, one to the motor for rotating. The switch powering the rails is moved to the center position prior to rotating the turntable or you will get the exact problem you are describing. I had this set-up years ago and it worked just fine for me, so we should be able to solve your dilema.
Yeah…I’ll say they have some splaining to do. The only way to get that to work with that Twin switch is to add a SPST switch, toggle or slide, to one wire on the output side of the twin or replace the twin with two DPDT center off toggles/slide switches. You need to be able to reverse direction of the motor for clockwise/counter clockwise operation of the TT bridge.
Lone Wolf & Santa Fe’s diagram won’t work either…there is no provision for reversing the TT motor. Simple just to use a separate transformer for the TT motor controlled by a DPDT center off switch.
I believe that they had it set up that way so You can control the speed of the TT with the variable DC throttle…but didn’t show You about the extra switches You need to turn one or the other off, when not being used.
A 6-8 VDC Transformer for the TT motor thru a DPDT center off switch to the motor would give You about the right speed for the TT movement…12 volt would be pretty fast.
If the Twin is truly a center-off switch instead of a DPDT switch as they describe, then there is no reason why it won’t work. They don’t mention any where that it is center-off on any of the packaging.
The only way it isn’t a center-off is if they changed it in the last 30 years! Entirely possible, but not sure why they would. If I remember right it isn’t entirely obvious, but you can feel that center section on the twin so you don’t have to be staring at it to tell. I think I’ve still got them tucked away somewhere. I can check when I get home to verify.
I just would like to say that I’m not doubting Your word…I have used many Atlas controls back in the 50’s on a couple layouts with common rail wiring, but I never had any need for the twin…had no TT and no reversing loops, which are reasons for the twin’s use. What I find hard to believe is that they do not state that in the packaging, that although it is a pair of DPDT switches, there is no mention of a center-off. In looking at the switch in a pic’, it does appear that the slide has enough room to be a center-off…I really hope it is for the OP’s sake. I would also be curious to see what the instructions show on the back side of the pkg, that they say are there on how to wire it. [;)]
I never assumed you were.[:)] I was just saying that I last used them myself 30ish years ago, so they may have changed between then and now. Curious to see what the OP will have to say about it if/when he checks his out.
You do not need a separate power supply for the turntable motor. Connect the power pack you are using to run your train to the twin at either the left or right side contacts (screws). Connect one of the switches to the turntable motor. Connect the other switch to the turntable track power. To use, have the switch for the motor in the center off position and the switch for the track power in the appropriate position to allow you to drive the engine onto the turntable without it shorting. Then, move the track power switch to the center off, and the turntable motor switch into either the up or down position and crank up your power pack to rotate the turntable. Once it is in the desire position, move the turntable motor switch back to the center off position, and move the track power switch to the appropriate position to drive it off without shorting, and be on your way.
^ what he said. It’s the exact diagram in the Atlas instruction sheet. Frank linked the PDF from the Atlas web site a few posts back in case you lost the ones that came with it.
