These HRB relay boards are designed to control 3 or 4 relays from one of the 4QD hand throttles. Often used for lights and horns on model locomotives they can be used in many other applications. The circuit allows control of either 3 or 4 relays with only 2 or 3 wires. It also has a number of ''break points'' on the circuit board that gives it a lot of flexibility to be used with [e.g. sound] systems that require isolated switch inputs.
Miniature locomotives often need to operate twin horns and lighting from the hand control box. This has usually meant using a 12 way cable and an expensive (or fiddly) connector. Often. it means running lighting or horn currents through to the hand control box – not a good idea as there is risk of fault currents blowing controllers etc.
This relay board solves all of these problems. It enables you to control twin horns and lighting with only two control wires. It uses properly suppressed relays, minimising chances of fault currents in the wrong place.
It measures approximately 76mm x 60mm. Two relays operate twin horns via one control wire, operating from a centre-off switch. Earthing the control wire operates one relay/horn, connecting to battery positive operates the second relay/horn.
The relay board will greatly simplify the wiring of most miniature locos. A 6 way IDC takes the two spare wires from the 8 core control cable, and screw terminals are provided for the horn and lighting wiring.
The board is manufactured with a number of ''break points'' that allow the relays to be isolated for use in many applications.
The lighting relay is a single wire operation, but there is space for a fourth relay so that another twin relay system can be implemented. Or the four relays could be worked independently (requiring four control wires).
- One wire operates twin horns (High for horn 1, Low for Horn 2)
- One wire operates lights.
- Relay continuous current handling: 10 amps at 24 volts.