Installation and Wiring Diagrams

Multi speed control

We’ve been asked for a way to switch a motor between a number of pre-set speeds [ multi speed control ]. Here’s a simple little circuit that we put together for the 4QD range but Read More

Double Heading Wiring Diagram [DNO]

This diagram shows how to connect two DNOs in different model locomotives together using the expansion port.     You can download a PDF version here. For the slave cable we recommend using a bulgin Read More

Driving the DNO by Raspberry Pi

Our DNO range is ideally suited for use as an interface between a Raspberry Pi, Arduino  etc, and a motor. The Pi can provide a PWM output via its GPIO pins and this can be Read More

Pro-150 Basic Wiring Diagram

This diagram shows a basic wiring scheme for the Pro-150 running on 24V with ignition and reversing switches. For clarity we haven’t shown the optional display / programmer which connects via 2 cables to its Read More

Motor Noise Suppression

Electric motors are electrically noisy, the sparks commonly seen at the brushes are a source of radio frequency interference [RFI] that can interfer with both the host controller and other systems. Good motor noise suppression Read More

Switching for Double Heading

We were asked for a diagram for a double heading switch that could let either loco be at the front of the pair, and could be facing either way. This seems to make selection of Read More

Fuses and Circuit Breakers

Choosing fuses and circuit breakers is a difficult subject…… Difficult because motor currents in most applications are very peaky. Difficult because the controller’s battery current is not the same as the motor current. Difficult because Read More

Radio Control Wiring Hints

Any radio controlled machine with motors has potential problems, and this page of radio control wiring hints hopefully helps to identify and solve them. The block diagram shows the electrical system of a typical radio Read More

Charging a 24V System From a 12V Source

One thing that sometimes puts people off 24v systems is the difficulty (and expense) in getting 24v chargers. Firstly, cheap 12v chargers are made for occasional use, for topping up car batteries. They do not Read More

Wiring for Push Button Use

This diagram shows how to connect a Pro or DNO (or earlier NTX and NCC) series controller for push button use, or with a centre-off switch. Note that the diode shown between the buttons must Read More

Loco Wiring: Hand Control & Horn Relay Board

4QD’s Reversing Bell throttle hand control and associated Horn Relay Board are designed to simplify miniature Loco wiring whilst maximising features available. The Reversing Bell throttle gives a dead man speed control and may be Read More

UNI / Egret Wiring Options

The Uni and Egret both have a 4 pin input connector, but only require 3 wires for input. This is done to allow different options to be selected by varying the input wiring. Standard 10K Read More

Good Wiring Practise

Our controllers get used in a wide variety of applications often switching large currents (several hundred amps perhaps) at around 20kHz. This makes the wiring used with them more critical, and this page tries to Read More

Multiple Controllers [Double Heading]

This page describes wiring that allows multiple Pro-150s and 4QD series controllers to be controlled from a single speed potentiometer. This is useful when double heading model locomotives. As the Pro-150 is a programmable controller, Read More

Double Heading Switch

We were asked for a system such that either loco could be at front and could be facing either way. This seems to make selection of reverse very complicated, but it is in fact quite Read More

Foot Pedal

4QD’s Bell throttle assembly is a finger-tip operated ‘position sensor’ which is also very suitable for use as a position sensor for a foot pedal operated throttle. The diagram shows how it might be done. Read More