Tortoise crossover wiring

[MikeyChris]

Hello All,

Another question about Tortoise wiring, specifically crossover wiring using series LED indicators. 

Since most common LEDs can only handle 15 to 20 ma, and wiring two Tortoise motors in parallel would probably draw more than that, I have a dilemma. The drawing below shows the wiring scheme I am using for my switch motors. For reasons beyond the scope of this situation, I am using a bi-polar 12 volt supply (±12VDC) to power the motors. I can play with the polarity of the voltage on pins 1 & 8 of the Tortoise to make the two motors in a crossover do what I want. However, to not cause over current in the LEDs, it looks like I will have to change my wiring scheme, and add a third wire to the control panel (C.P.) so the second motor bypasses the LEDs. I was hoping NOT to do this since the terminal blocks (TB's), Control Panel (CP), and regulator for the ±12VDC are physically located in a central location, and (obviously) the switch motors are scattered around the layout).

I was hoping someone here has done this and can offer suggestions. Thanx.

Mike

[MikeyChris]

Oops, I forgot to add that I was considering wiring the two motors in series, but wondered if the series connection of the two motors and two LEDs would lower the voltage to the motors to a value below which they would operate in a reasonable time frame. Of course, I will experiment with this, but would still like to hear from someone who has actually done it. Thanx!

Mike

[7j43k]

You could put resistors in parallel with the LED's.

Finding the value of the resistor is easy:  for the circuit in the drawing, measure the current through the LED's and the voltage across one pair.  The value is V / .5I.  

 

Or so I think.  Ya might wanna think through on your own.  It's not my equipment that's gonna fry.

 

 

Ed

[Anonymous]

I will post photos once I download them from my phone if you need them.

The following is my wiring color coding"

Common bus: orange

+12VDC: purple

-12 VDC: Brown

Control wire from SPST: Blue

On my club module I used +12VDC, -12VDC and ground.  I ran the common bus wire to contact 1 or 8 on both motors depending on how each motor is oriented.  The common wire goes back to the 12VDC power supply common terminal.  I then ran a control wire between the 2 motors on the unused contact 1 or 8 (blue wire).  The blue wire then goes to the center contact on a SPST switch.  +12VDC and -12VDC is connected to the other 2 contacts on the SPST.   

Essentially this is the diagram 2 method of wiring Circuitron reccommends, without the second SPST.  It works just fine.

Circuitron says you can either use the aux contacts or the main power.  The aux contacts are probably the best option because you can dial in the voltage from the aux contacts without affecting anything else.  Here is the circuitron tech note: http://www.circuitron.com/index_files/AN/an-6000-02.pdf

 

 

 

 

 

 

[DigitalGriffin]

You could create a parallel circuit attached to leg 8 of the tortoise. On leg 1 is a small value resistor. On leg 2 is a another small value resistor in series with the leds. This would only induce a small voltage drop to motors since they are small resistors in paralel but force the current to be split between leg 1 and leg 2 with roughly 30% of current going through the resistor leg. (Depends on the leds forward voltage drop which varies)

[DigitalGriffin]

When i say leg 1 and leg 2 i mean of the parallel.ciruit...not tortoise contacts.