Searched around and did not see this question, so I'm posting a new thread. Question? How would the below diagram connect to a power source? I understand for a two-pole tortoise control, we'd have V- and V+. Where one is used for a "common bus". Makes sense. What I want to know is with separate V- and V+, WHERE does the third common bus get connected? See the below diagram. I pulled this from a MR article I found. The wiring and truth tables to set it up all make sense. I'm just having a hard time understanding the source. It looks to me like there is a three pole source. Common, V-, and V+. What am I missing? Thanks.
You can use 2 DC power supplies. Connect the positive from power supply Number 1 with the negative of power supply Number 2 for the common connection. Use the Negative of power supply number 1 as the V- and the Positive of power supply 2 as the V+. I think you can also do it with an AC power supply, using diodes to give you the positive and negative for half wave DC going to the rotary switch and the common being the other leg of the AC power supply. What issue of MR is it out of? Richard
What you have is the bipolar DC wiring option, which allows the use of single pole-double throw switches and simplified wiring. It uses two DC power sources of not more than 12 volts which are wired in series as fire5506 describes above. Wire the + side of power source one to V+ and the negative side of power source V-. Then wire the - side of power source one to the + side of power source two and wire the common buss into that connection. http://www.circuitron.com/index_files/INS/800-6000ins.pdf Series connections like that are generally used to create a single circuit of double the voltage of the power packs, and this does do that. But circuits that bypass one power pack or the other are bipolar on the common buss because the same wire carries + from one power pack and - from the other--thus the wiring is simplified and single pole control switches can be used, yet nothing gets shorted out. Twelve volt circuits can be created that go either direction without affecting the whole 24V circuit. If you don't understand all that, don't feel bad, because I'm not entirely sure I do myself--and I'm not entirely sure I'm right about it. But the common buss does get connected to the series connection between the two power packs.
