A stupid question about a switch

[Adam Y.]

4-Pole 3-Position Switch Why does this switch have more than three possible positions? It's been annoying me since I started working on a project for work. According to the specification sheet the sheet has three active posistions which makes sense. Does that mean all the other positions should be open?

[Al Skierkiewicz]

Adam,
Unfortunately, your link goes to a Digikey search page and not the part in question. I think what you may be asking is related to switch design. Frequently, switches which have three positions (handle/actuator) have a "center off" and are listed as ON-OFF-ON. In the switch you describe, there are three positions with no "center off" and those would be listed as ON-ON-ON. In your description the switch could have 16 terminals. The three positions would connect first, rows 1 to 2, then second, rows 2 to 3 and finally rows 3 to 4 for each pole. I have seen switches that have one common row that connects to each of the three active rows, but those are rare and expensive, almost custom.

[Adam Y.]

Originally Posted by Al Skierkiewicz

Adam,
Unfortunately, your link goes to a Digikey search page and not the part in question. I think what you may be asking is related to switch design. Frequently, switches which have three positions (handle/actuator) have a "center off" and are listed as ON-OFF-ON. In the switch you describe, there are three positions with no "center off" and those would be listed as ON-ON-ON. In your description the switch could have 16 terminals. The three positions would connect first, rows 1 to 2, then second, rows 2 to 3 and finally rows 3 to 4 for each pole. I have seen switches that have one common row that connects to each of the three active rows, but those are rare and expensive, almost custom.

I wasn't explicit enough about my question. My question is why you would have more than three possible positions on this switch when the part description says three. Essentially, it just repeats the same on-on-on pattern four times for a total of twelve differnt positions and the number of positions that are available is adjustable by a stop. My best guess is that they just used the same design for all of their switches just to make it cheaper???The switch

[Al Skierkiewicz]

Adam and John,
In this series of switch, a few internal part changes cause the product to go from a single pole 12 position switch to a 4 pole 2 position switch. The outside terminals, the switch body and the actuator remain the same as well as the outside footprint. Please note that for a 4 pole switch only positions 2 and 3 are active. For a single pole switch positions 02 to 12 are active.

Check at the bottom of the sheet and you will see the layout for each of the four parts, 1 pole, 2 pole, 3 pole and 4 pole. Only the center pins vary from part to part. If you visualize the switch internals for the four pole, the switch is divided into quadrants with each quad containing 3 terminals. The center terminal is common and position 02 connects the common with the terminal to the left of it. Position 03 connects the common with the terminal to the right of it.

My discussion above holds true for lever actuated switches. This switch is a rotary device and construction and operation are quite different.