Rotation
Most machines in Feedback run on rotation: spinning shafts carrying power from a source to the machines that use it.
The basics
- A source makes rotation: Water Wheel, Steam Engine, Engine, Hand Crank, Motor.
- Shafts, cogs, gearboxes and pulleys carry it.
- Machines use it: hammers (through a Crank Linkage), presses, mills, lathes and so on.
Everything touching along a shaft line is one network, and the whole network turns together.
Power: Su
Every source can carry a certain load, and every machine adds load. Both are measured in Su. A machine's load is printed on it.
| Source | Su | Speed |
|---|---|---|
| Hand Crank | 12 | 32 RPM |
| Steam Engine | 64 | 16 RPM |
| Water Wheel | 256 | 4 RPM per side of flowing water, up to 16 |
| Engine | by design | by design |
| Machine | Su |
|---|---|
| Controller | 2 |
| Pump | 8 |
| Wire Drawer | 30 |
| Drill Press | 35 |
| Powered Bellows | 40 |
| Lathe | 40 |
| Grinding Wheel | 45 |
| Rolling Mill | 50 |
| Mechanical Hammer | 80 |
| Mechanical Press | 90 |
A water wheel carries three hammers (240 Su) but not four.
Sources on the same network add their capacity together.
When it's too much
A network carrying more than its sources can give is overloaded. It isn't driven any more, and it winds down to a stop under its own load. Nothing breaks.
You'll know because the sources smoke and creak: every so often when the network is close to its limit, and more insistently when it's overloaded. Jade shows Straining (above 90% of capacity) or Overloaded on any part of the network. A straining network takes much longer to come up to speed, because only the spare 10% is left to accelerate it. Take some load off, or add another source.
Speed and momentum
A network doesn't jump to speed. It spins up using whatever spare power it has, so a lightly loaded network gets up to speed fast and a heavily loaded one takes a while. Heavy things on the line (water wheels, steam engines, big cogs) make it slower to change speed in both directions.
Cut the power and a network coasts down instead of stopping dead. Machines on it keep working, a little, until it stops. That matters when you're trying to stop a hammer at exactly the right moment.
Jade describes speed in words: Stopped, Turning slowly (under 8 RPM), Turning, Spinning fast (24 RPM and up).
Friction
Every shaft, cog and gearbox costs a little power, and more the faster it spins:
| Part | Friction per RPM |
|---|---|
| Bearing | 0.04 Su |
| Shaft, Small Cog, Pulley | 0.1 Su |
| Large Cog | 0.15 Su |
| Gearbox, Flywheel | 0.2 Su |
So twenty shafts at 16 RPM cost 32 Su, half a steam engine. A network speeds up until its spare power runs out, so a long run doesn't stall; it just turns slower. A stopped shaft costs nothing. Gearing a branch up to a higher speed makes its friction costlier still. Distance itself is free: every block in the network costs the same wherever the machine is.
Gearing
Gearing trades speed for force. Slow a line down with cogs and each turn pushes harder; speed it up and each turn pushes softer. For the hammer that's the difference between a blow that shapes steel and one that does nothing. See Crank Linkage.
Stopping things
- A Clutch disconnects everything past it.
- An Overspeed Trip disconnects automatically above 48 RPM.
- A Flywheel smooths a line out and makes it coast longer.
- A Timer or Controller can work a clutch for you.
Remember that disconnecting doesn't brake anything. The far side coasts down.