I've built a small HO module with a switching puzzle layout that has 10 turnouts powered by tortoise switch machines. I'm using the standard DC wiring option with all of the DPDT switches in parallel. Miraculously, everything appears to work properly. All of the switches switch properly, including two crossovers which I've wired to the same switch. So far so good, especially for a wiring noob like me.
My only concern is a surprisingly loud hum coming from the layout when I switch on the power to the turnouts and they're all stalled. Is that normal? I don't want to cook $150 worth of switch machines because of a stupid wiring mistake. I'm using the DC track outputs of a basic 16v power pack set at 75%, which my multimeter agrees is 12v.
Any idea what the hum is? I searched this forum but didn't see the topic posted previously.
I think they hum because they do not know the words.
Seriously, I searched this Electronics and DCC for tortoise and came up with what was posted a few days ago.
http://cs.trains.com/trccs/forums/t/142409.aspx
Rich
If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.
Any chance that basic pack has some pulse built in? Pulse would cause them to hum but it shouldn't hurt them.
Martin Myers
12 Volts is too much. Turn the voltage down to a point that the tortoise machines barely still move when you change their position. It could also be the fact that your power pack has very poor electrical filtering and is putting out an AC pulse instead of a smooth DC current. A better quality power pack should solve this problem.
Ditto the 12V being abit much. They can handle it, but they don;t need it. 9V is plenty. The hum is mostly due tot he fact that a cheap power pack isn;t goign to have a filtered output. In fact DC motors start better when they AREN'T fed from filtered DC. By not filtering the DC, there are still slight pulses at 60Hz in the output. It's DC, none of these pusles goes below 0 volts, but it's not filtered DC. If you look up the terms like half wave, full wave, and filtered DC there will be plenty of examples of the wave forms of these various variations of DC power. Your best bet is to find a small filtered DC power supply, often found in a 'wall wart' configuration that plugs right in. 9V is good, and with 10 Tortoises, a half amp is more than sufficient.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Thanks to everyone for the fast, friendly, and informative responses.
As a followup, I'm using the DC track output of an MRC Railpower 1300 throttle that came with a set for my son a few years ago. Turning down to 50% power or about 8v did decease the hum considerably, so I think you've got me going in the right direction.
Would Radio Shack have a filtered 9V 500mA wall wart, or is there a well known online store I should know about? (NewEgg.com is my trusted first choice for computer components, but when it comes to Model RR stuff, I've got nothin'.)
You should be able to find a wall wart at Radio Shack or Wal-Mart for under $10.00.
I happened to have several old cell phone chargers that are 9V 300MAH that work great and don't cost anyhthing.
As a matter of fact I have one wall wart that is 5V 300MAH that works the tortoise machines. It is slow but I have it working 5 machines with no problems.
I would not exceed 12V or you may damage the torotoise machines.
Bill
The real buzz-killer is a filter or smoothing capacitor wired parallel to each rectifier diode. The last circuit diagram in the thread referenced above shows how it's done.
Without the capacitor, the machine is getting 60hz half-wave pulsed power - sort of like inverted Us with underlines between. The capacitor lowers the peak of the U, then fills in the intervening space with stored power. It will actually INCREASE the RMS voltage to the machine, while slightly lowering that buzz-producing peak.
Chuck (modeling Central Japan in September, 1964)
richg1998 I think they hum because they do not know the words. Rich
Darn, you beat me to it...
I have figured out what is wrong with my brain! On the left side nothing works right, and on the right side there is nothing left!
tomikawaTTThe real buzz-killer is a filter or smoothing capacitor wired parallel to each rectifier diode. The last circuit diagram in the thread referenced above shows how it's done.
I believe that Chuck meant parallel to the tortoise, not parallel to the diode. Only tiny noise filtering caps should go across diodes.
The mind is like a parachute. It works better when it's open. www.stremy.net
I also have Tortoise Switch Machines,i first wired them with double pole single throw toggle switches.This meant when it switched the turnout with the double pole switchest to the Tortoise machine and it made its move it stalled,meaning it still had power on it which made it humm.With over 75 Tortoise machines doing this it really made a lot of noise.So what i did was change the Toggle switches to double pole double throw with momentary contacts ( meaning when you let off the toggle switch it breaks the contact to the switch machine ).This way they don't have power to them once you release the toggle switch.These switch machines will be ok in stalled position but i personally didn't like the Humming noise. Harold
Great solution - Except. Once power is cut, the Tortoise can 'relax' and walk back a little. I hope your spring wire makes up for that. This whole thread just has me puzzles. I wired mine(and the club ones) with the 'bi-polar' scheme described in the Tortoise instructions. A small 15VAC wall wart(850 ma) and a pair of diodes from the local RS. I have no 'buzzing', and a large staging area with something like 23 Tortoises(I used a Miniatronics 16VAC/800 ma plug-in transformer). I would have expected lots of 1/2 wave 'buzz' with this installation(based on the above posts). Maybe I need to have my hearing checked?
Jim
Modeling BNSF and Milwaukee Road in SW Wisconsin
Works on on my friend's N scale layout with hand-laid turnouts. He was set on using Lenz LS-150 stationary decoders so his Tortoises are controlled by momentary pushbuttons. They spring back slightly but still maintain good pressure on the points. One thing we found with the LS-150's is if you set them for say a 5 second output pulse, you can;t throw another turnout until the 5 seconds expires. He also has some of the GSB jackscrew type switch motors which automatically cut out the motor at the end of the throw anyway, those work well with the LS-150 and there aren't too many other options that would work. And if you think Tortoises are loud....
jrbernier Great solution - Except. Once power is cut, the Tortoise can 'relax' and walk back a little. I hope your spring wire makes up for that. This whole thread just has me puzzles. I wired mine(and the club ones) with the 'bi-polar' scheme described in the Tortoise instructions. A small 15VAC wall wart(850 ma) and a pair of diodes from the local RS. I have no 'buzzing', and a large staging area with something like 23 Tortoises(I used a Miniatronics 16VAC/800 ma plug-in transformer). I would have expected lots of 1/2 wave 'buzz' with this installation(based on the above posts). Maybe I need to have my hearing checked? Jim
You can also use a DC walwart and have the benefit of using indicator diodes in-line with the Tortoises (if desired).
Engineer Jeff NS Nut Visit my layout at: http://www.thebinks.com/trains/
You can use the 'steering' diodes plus one set of the contacts on the tortoise to do LEDs with the AC power supply too. Something I figured out while wiring my friend's layout, originally he was using a second set of diodes plus the LEDs to make panel indicators, I figured out how to wire it so you only needed one set of diodes.
OK wow, saves like 10 cents per Tortoise if you buy the diodes in bulk
rrinker You can use the 'steering' diodes plus one set of the contacts on the tortoise to do LEDs with the AC power supply too. Something I figured out while wiring my friend's layout, originally he was using a second set of diodes plus the LEDs to make panel indicators, I figured out how to wire it so you only needed one set of diodes. OK wow, saves like 10 cents per Tortoise if you buy the diodes in bulk --Randy
Yes, you can but it involves more wiring, which can add up, depending on the number of Tortoises. The in-line LEDs also drop 2-3V which makes the Tortoise voltage closer to 9V (which you recommend) when using a 12V supply.
Jeff,
You can use 'bi-color' LED's in-line with the Totroise using the 'polarized' wiring scheme as well. I really like using the bi-color LED's. They 'dim' when the motor is reversing and then 'pop' to the correct color once the Tortoise is 'stalled'. This provides 'proof' that the Tortoise is moving. It is not a positive turnout alignment like using one of the Tortoise contacts, but sure saves a lot of wiring.
jrbernier You can use 'bi-color' LED's in-line with the Totroise using the 'polarized' wiring scheme as well. I really like using the bi-color LED's. They 'dim' when the motor is reversing and then 'pop' to the correct color once the Tortoise is 'stalled'.
jrbernier Jeff, You can use 'bi-color' LED's in-line with the Totroise using the 'polarized' wiring scheme as well. I really like using the bi-color LED's. They 'dim' when the motor is reversing and then 'pop' to the correct color once the Tortoise is 'stalled'. This provides 'proof' that the Tortoise is moving. It is not a positive turnout alignment like using one of the Tortoise contacts, but sure saves a lot of wiring. Jim
Yes, I am using them on my staging yards with DS64s driving the output.
On my main line control panels I use back to back red/green LEDs with DS64s driving them.