Installation and Wiring Diagrams

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

Motors are electrically noisy. Electrical noise reduces system reliability and can on rare occasion cause the MOSFETs in a controller to latch up and fail [more details here]. To help reduce this noise some or Read More

Switching for Double Heading

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

Fuses and Circuit Breakers

This 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 some users haven’t really Read More

Radio Control Wiring Hints

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

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

  Occasionally our controllers are used in industrial machines. Our controllers are PWM, switching large currents (several hundred amps perhaps) at around 20kHz. This switching of high currents makes the wiring used with them more Read More

PRO-150 Double Heading

As the Pro-150 is a programmable controller, two Pro-150 that are set up identically will behave identically so that double heading them is very simple and doesn’t need the complication of an extra connector. This Read More

Switching for Double Heading

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