Semco Motion Products / Larsen Mfg.                        +1 801-876-2111 

Power a sign without tangling wires

How do you power a rotating sign without tangling the wires?

how to rotate wires

The answer to have a rotating or revolving power source is a slip-ring and brush assembly. In a standard lighted sign, you would run your power cord up through the sign pole to the lights inside the sign. Most times this would be a 3-wire power cord with hot, neutral, and ground, here in the US we usually use 115VAC power. The display rotator is placed between the sign pole and the sign frame. (see illustration below)

If you put one of our rotators between the sign pole and the sign you can turn the sign. This type of rotator has a box frame to attach to the sign pole, it is stationary – it does not move. On the box, there are two bearings and a shaft with a plate attached to it. On the shaft is a slip ring assembly. Each ring has a wire soldered inside it. the wires pass up through a hole in the shaft and out through the top turntable plate that is also connected to the shaft.
When the shaft turns so does the slip ring and the wires. The rings are made of bronze and they conduct electricity to the wires.

The brush assembly is stationary along with the sign pole, and the box frame. the incoming power connects to the brushes; one wire per brush. The brush has a brass housing and a copper, spring-loaded brush. the brush conducts electricity. Incoming power connects to each brush which connects to the corresponding ring. Electricity travels up the sign pole to the brushes, passes through the brushes to the rings, and then through the electrical wires up though the rotator shaft and into the sign to the lights. The brushes are in constant spring loaded contact with the rings so there is always power even as the rings are turning. The wires don’t actually move, they simply turn with the shaft.

Power simply travels or passes through the slip ring assembly to the sign. The sign lights up whether the rotator is stopped or turning. Now you know the secret of why the wires don’t tangle up as the sign turns.