I’m trying to get power to my turntable. I want to be able to rotate it 180 degrees and still get power. My turntable is manually operated. Any suggestions will be appreciated.
Phosphor-Bronze is a springy metal used for sliding contacts - you can buy a sheet from Amazon. Alternatively, use the contacts you removed from the Jackson and Sharp coach bogies (both Accucraft and Bachmann have them and most of us remove them.)
The springy sliders can be attached the to running rails.
Then the question is whether you want power at all positions or just at the 180 point - in other words, are you turning the loco completely then heading off the way you came.
I’ve heard of turntables where the support rail that runs all the way round the pit is split, each half carries power to one rail, and the wheels that support the bridge collect power; one end connected to one half of the pit rail and the other end from the other. This works well for the 180 degree turn as long as power is off when the support wheels transition over the gap.
Alternatively, attach the contacts to the rails at each end and use the springy contacts to rub on brass round-head screws strategically located at the rails on the rim of the pit.
Another idea that I have heard, but never tried is to use a 1/4" phone jack and plug as the pivot point in the center of the table. The phone plugs come in two and three conductor styles and the jacks come either standard, or with a switch included that opens when the plug is inserted. This would power the table rails at all times.
One more thing to consider, since you mention 180 degrees. That sounds like you don’t need “continuous rotation,” where you can keep turning indefinitely, but might be OK with a back-and-forth 180 motion.
If that’s the case, a coil or loop of wire, with sufficient flexibility, might be incorporated in such a way as to not be too obvious.
For example, “SJ” cable, or anything decently flexible, outdoor-rated, and buy by-the-foot at Home Depot / etc. might work.
You might do a mockup with the cable and a pivoting 2x4, to see how the cable will reliably lay at differing distances from the turntable pivot.
Then comes the hiding of it…
It’s possible that it could be hidden up within the TT bridge structure, and just wind and unwind all within that footprint.
 The point behind this suggestion is that the electrical connections are always hard-wired, with no wiping contacts that may oxidize, loose their springiness, or otherwise fail.
Does your turntable run on rollers on the circumference?
If so, you could make that one pole and the other pole the kingpin
Alternatively I have seen metal thumbtacks and nickel plated brass strips used in the circumference to energize the turntable rail with whatever track it is aligned with. Probably preferable unless you run 3 rail… polarity is always right