January 2019

1.5kW Induction Motor Speed Controller

An advanced controller designed for induction motor applications, and capable of driving motors up to 1.5kW (2 HP). Induction motor speed control requires adjustment of both frequency and voltage parameters and this design ticks all the boxes and enables advanced constructors to build their own 230V  a.c. speed controller.

Suitable for eg swimming pool pumps (has a power-saving pool pump mode), irrigation equipment or machines etc (built-in tool spin-up mode), and can also work with 3-phase equipment. (Please refer to the text for details of suitability with single-phase induction motors.) Includes many safety and limiter features.

This advanced design is based on a PIC microcontroller and opto-isolated 3-phase intelligent power module. In Part One this month, induction motor basics and circuit outline are considered and construction begins next month.

The Induction Motor Controller is a high voltage design with mains (and higher) voltages present throughout. Suitable for skilled and experienced constructors only.

Altronics Mega Box

Make your Arduino projects easier to build and look much more professional with this clever self-contained Arduino prototyping test-bed system from Australian supplier Altronics.

The kit includes a pre-cut plastic instrument case, 16×2 LCD, illuminated push switches, IR receiver, rotary encoder and more besides. Compatible with most Arduino shields (dimensions permitting) and is also suitable for novices to construct.

Using Cheap Asian Electronic Modules (Part 12)

This month we look at a number of applications for the nRF24L01+ 2.4GHz wireless data transceiver, which can handle up to 2Mb/s over modest distances in the 2.4-2.5GHz ISM band. Its SPI interface makes is easy to use with any microcontroller.

Teach-In 2019 – Powering electronics
Part 2: Transformers and Rectifiers

A welcome and long-overdue educational primer dedicated to the principles of power supply design in electronics. This month, the basics of AC to DC conversion are explored, with rectification and smoothing techniques explained in full. If you’re interested in powering your electronics projects, or refreshing your knowledge of power supplies, this series is for you!

Please Take Note
The circuit shown in Fig.2.18 (page 43 of January EPE) is incorrect. The two secondary windings should be in parallel and not in series (the corrected circuit diagram is on page 50 in the February 2019 issue). The stripboard wiring layouts (Fig. 2.19) are correctly shown.

Audio Out

Part 2 of the mini-series describing offering a General Ultra-Low Power (Consumption) or ‘GULP’ combo amplifier-speaker ideal for practice/ studio or synth duties. This month a circuit and PCB are offered for this thoroughly-sorted amp circuit.

PIC n’ MIX

In his final article for us, Mike O’Keeffe rounds off his mini series describing a PIC-based digital test meter.

PIC n’ MIX Extra!
Designing PCBs with EagleCAD (Part 1)

Mike Hibbett returns with a new series dedicated to getting to grips with EagleCAD, starting this month by introducing the basics behind printed circuit board design and implementation. PIC n’ MIX promises to be a great series for hobbyists wishing to create their own printed circuit boards – don’t miss it!

Electronics Building Blocks
DC Motor Speed Controller

Checking out a cheap and cheerful 30-amp speed controller sourced from the web. Looks can be deceptive, and we find out whether or not the specs. are too good to be true.

Also in this issue:

• Techno Talk – does digital data make a hard disk heavier?
• Net Work – forthcoming taxes on digital services, and eco-friendly printer fonts
• Circuit Surgery – Introduction to Circuit Simulation with LTSpice (Part 4)
• Max’s Cool Beans – a welcome return of this entertaining blog column written by Clive ‘Max’ Maxfield

Next month

Teach-In 2019 (Part 3): linear voltage regulators; 1.5kW Induction Motor Controller (Part 2); low-cost electronic modules (Part 13) – a microwave Doppler module and a soil moisture monitor; Arduino Mega Box Music Player.