25 February 2021
Here is one of the many SRA’s that we have designed and manufactured for large radar applications – military or weather.
A radar SRA like this has high voltage and high current. The former requires very good channel isolation to avoid arcing throughout its operational life. But, on the other hand, this cannot be accomplished by making the design larger than the customer’s available space. The combination of high voltage and high current means that there is a significant amount of heat to dissipate.
Large radars like this may operate continuously for long periods and this raises the issue of life-time operation and maintenance. There are various design possibilities that Pandect considers that extend the life between needing to perform any maintenance, and the ease of maintenance.
If a radar SRA is mounted on a fixed, ground installation its vibration profile is one type. If it is mounted on a large surface vehicle the vibration to which it wil be subject will have a different profile. If it is mounted on a ship it will have a yet different vibration profile to tolerate. With a ship-mounted SRA there is the issue of a particularly robust resistance to water ingress being necessary. We have some SRA’s mounted on the decks of warships where they are frequently washed over by salt waves. How much environmental protection a design needs has an influence on how much torque is needed to rotate the joint.
If a design like this is installed on a mountain in the tropics it may have to operate over quite a wide temperature range.
You will see from the picture that we designed this radar SRA as a cylindrical one with the power rings outside and the hundreds of signal rings inside – a concentric cylinder design- in order to keep the axial length of the SRA within the customer’s requirements. A pancake design would have had a shorter axial length but its diameter would have exceeded the customer’s available envelope. Sometimes we design and supply cylindrical solutions with more than two concentric rings sets.
This design of ours is more than just a very complex SRA- we integrated into it a hydraulic rotary joint to cool the radar’s electronics. Instead we could have integrated a pneumatic rotary joint.
We are supplying other radar SRA’s with μwave rotary joints inside them.
Of course, a design like this could also have a fibre optic rotary joint inside it as well.