My name is Alfin , and I am currently working on a project that references the OTPS system from Blue Robotics.
I have read through the OTPS product specification and noticed that the output from the topside unit is listed as 400VDC. However, in the Power Enclosure documentation, the input voltage is stated as 200VDC.
A voltage is a relative electrical potential, and the conventional zero point of any circuit is a point specified as “ground” (or “earth”).
As is shown in the picture you included, pin 3 is connected to the chassis of the power enclosure, which is considered (for that system) to be the ground. Pin 1 is then +200 VDC (above the chassis ground level), and Pin 2 is -200 VDC (below the ground level), so there is a maximum potential between the chassis and any wire of 200 V, but the power being provided through the two high voltage wires is at 400 VDC (relative to each other).
This kind of split improves the safety of the system, because it makes it harder for anything outside the cable to be exposed to the full 400 V, even if the cable gets partially cut.
By the way, I’ve made your message into a public post, as this kind of information is relevant to the whole community
