Transformers – The Different Types of Electrical Transformers


The Different Types of Transformers

Transformers – Step Up, Step Down, Single Phase, Three Phase

Transformers either ‘step up’ or ‘step down’ AC voltage. They do do by magnetic induction.

Step Down types reduce the voltage coming out, compared to the voltage going in. These are the most common type.

Step Up types have a higher output voltage than an input voltage. These are used for example at power stations to boost up the voltage that is fed onto the pylons. Higher voltage reduces losses over distance. It is then reduced again as it approaches towns where the users are located.

There are both ‘Single Phase’ Transformers, and ‘Three phase’ Transformers.

Single Phase Transformers have one ‘Primary’ coil, and one ‘Secondary’ coil. The Alternating Current is fed into the Primary, and comes out of the Secondary.

Three Phase types have three Primary coil windings, and yes you guessed it correctly, three secondary (output) coil windings.

Transformers are available in a wide variety of voltage and current outputs, ranging from a few volts up to thousands of volts, for high voltage electricity distribution.

Are Transformers AC or DC?

Transformers work by electromagnetic induction.

To generate electricity you need to move a varying magnetic field within a coil of wire.

This can be done in two ways:-

Firstly you could get a coil of copper wire and move a magnet in and out of the coil, which would generate electricity.

As the magnetic would be moving in and out of the coil, the magnetic ‘field strength’ would be continually changing.

If a suitable meter was connected to each of the two ends of the coil wires, then it would be showing a variable voltage.

This variable voltage is AC.

The second way to generate Alternating Current is to substitute the moving magnet used in the first method, with an alternating voltage.

Transformers work by this method, and an Alternating Voltage is run through the first coil (known as the ‘Primary Winding’), which induces a (normally) different voltage in the second coil (known as the ‘Secondary Winding’).

By varying the ratio of coil windings between the Primary Winding and the Secondary Winding, you can alter the output voltage to the desired level.

The transformer output is usually fixed at the time of manufacture, though some transformers have ‘tapped windings’ which are physical connection at different points along the transformer winding, allowing different voltages to be selected.

Transformer Construction

Coming soon….

Single Phase Transformers How They Work

How to Reverse the Direction of a Three Phase Induction Motor

How to reverse the direction of a three-phase induction motor.

Reversing the direction of a three phase Induction Motor is useful in a number of situations.

For example in a electric winch or elvevator (lift), there is a requirement for the motor to reverse.


reversing motor direction
Swap any two of the three ‘phase’ connections around, to reverse induction motor direction.

To reverse a three phase induction motor, swap over any two of the three ‘phase’ connections in the motor terminal connection box.

Warning: Only attempt to do this if you have been trained, as over 400 volts is involved. Also obtain all necessary ‘Permit To Work’ documentation, and the locks and keys, for the isolator ‘lock off’.

Induction Motor Servicing Tips For Ships & Factories

Phasing Out – Three Phase Induction Motors – on ships

Phasing out a Three Phase Induction motor, onboard ships (or on land)  is the process of identifying both ends of each of the three stator coils (3 phase motor).

What have Oranges got to do with Radios?

I once read an article by an educational research group that stated that students would retain facts better if two UNRELATED objects were put together in the picture.

Based on this article I decided to put fresh oranges in the background of an advert idea for a Walkie-Talkie company.

The advert has not yet been widely published, or compared against other adverts in the same media publications. Therefore objective comparisons cannot be made, or measured.

I will update this post if the advert gets used.

The use of the words “Grab a pear of these” was deliberately chosen, as the eyes see oranges, and not Pears.

Humans notice unusual things like this. Its an orange, not a pear.

Want proof of what I just said; then imagine a green elf walking down the high street. You would probably notice it, as its not the ‘norm’.

If I then asked you to name the make of car that just drove past 30 seconds ago with two children in, you might well struggle. This is because it is normal for cars to pass by with children inside.

Time is Money Advert

Time is money – This is an advert idea that I came up with entitled, ‘Time is Money’

The idea behind it, is that two-way-radio can save companies time, and as employees cost money for their time, by using two-way-radio, companies save money as well.

Insulation Resistance Tester

An insulation resistance tester is a piece of test equipment, used to test insulation resistance between connections.

One use of the tester is to test three-phase AC induction motor stators.

A stator in a three-phase induction motor consists of three sets of tightly wound coils.

The coils are wound together and next to each other, and electrically separated by a layer of insulation on the copper wire.

Each copper winding has two ends.

As there are three sets of windings, that means there are six coil ends in total.

Each end is connected to form either a star or delta configuration.

For the induction motor to work, there needs to be a high level of electrical resistance between each of the three coils.

This is known as ‘insulation resistance’, and a tester is used to measure it.

Electrical fault finding Experience


Fault Finding Experience

Experience of electrical fault finding Marine electrical & electronic systems (both practical & also teaching electro-technical officers &  Cadets in Marine Industry.

Marine permit to Work Procedures.

Fault finding of Single & Three Phase electrical systems used both on Marine environments (Insulated Neutral), and land based Star & Delta based systems.

Experience of Programming Variable Speed Drives, and fault finding cabling supplying the VSD, and from VSD to Induction Motor.

Experience of both teaching and installation of three phase Direct Online Starters (DOL) to Marine Industry students from UK & Internationally.

DOL experience includes, contact inspection and coil replacement of Contactor; fault finding of issues such as ‘Single Phasing’ faults, caused by loose motor connections in terminal box (ships vibration), broken motor Stator, mechanical damage due to to supply cable damage etc.

Experience of  three phase Star-Delta Starter inspection, servicing and fault finding.

Experience of Motor ‘Phasing Out‘ in the case of unidentified Stator connections.

Cable fault finding, though half-split, Input-Output and other methods.

Ships generator / alternator servicing & maintenance checks, including, bearing clearance & wear, Insulation Resistance testing using Insulation Resistance Tester, Stator Continuity checks using  specialist MicroOhmmeter.

Fault finding checks and fault finding on 550 Volt mining equipment starters.

Marine Switchboard maintenance, including ‘racking out’ circuit breakers to check bus bar connections, arc chutes etc. Checking Marine Circuit breakers for trip times using current injection test set.

Auto-Transformer (as used on some Ships Bow-Thrusters) testing and maintenance.

Three Phase Induction Motor stripping down, testing and servicing. Bearing replacement, IR Testing, Continuity Testing, damage inspection, re-assembly & test rig using Clamp Meter, RPM meter & calculations.

Over Current Relay (OCR) testing on test rig. Trip times etc. Electronic, Magnetic & Thermal types.

Delta-Delta Transformer testing.

Delta connected Single Phase Transformer configuration (as used on ships).

Single Phase Transformers, testing and connection (Step up, and step down).

Ships Earth Fault Alarm board testing and maintenance, using Line Tester etc.

Earth Fault testing on an Insulated neutral system.

Supply Synchronisation using simulator, to ensure shore-side and ships generators supplies are in phase before connection. Inductive and capacitive loads.

Radio Communications Fault Finding, including coaxial cable faults, bench testing using Radio Communications Test Set, SWR Meter, Spectrum Analyser, PC software programming of radio equipment, board level repair of two-way radio systems used on land and on ships.

Craig Miles | LinkedIn

Blue is the colour

According to some research I read recently, most adults prefer the colour blue.

This is why it is a popular colour for logo design and company advertising.

Have a look round and put this to the test. Think Facebook for instance.

Blue is considered to signify calmness and strength, whereas the colour red signifies danger (in nature), and excitement in advertising. Think of Ferrari cars, and Coca Cola. Both use red, and both are promoting fun and excitement.