What happens when you pour water on an induction motor

Pouring water on an Induction Motor may stop it working, due to the lowering of the insulation resistance of the internal motor coil windings.

The coil windings are located inside the metal case of the induction motor, and are what generates a magnetic field, which makes the motor turn.

This article will focus on what are known as ‘three phase’ Induction Motors, which have three sets of coil windings inside the motor.

The internal motor windings are wound together in a component known as a ‘Stator’.

Each winding is electrically separated by an insulation layer on the copper wire that makes up a stator winding.

Therefore there should be a high level of electrical resistance between each of the three coils.

This ‘Insulation Resistance’ is typically above 2 Mega Ohms in a correctly operating Induction Motor.

However if the coil windings became wet, then the insulation resistance would drop to a low level, which would prevent the motor from operating, due to a short circuit between the coil windings.

The good news is that induction motors can usually be dried out, and therefore returned to having a high insulation resistance between the Stator coils.

Drying out the stator coils can be done with gentle heating methods.

It is of course vital that the motor is disconnected from the electricity supply, and that only a qualified person carries out the work.

@acraigmiles

Motivation – What Motivates You?

What Motivates You (Passions)

I regularly ask myself the question ‘what motivates me in life’.

So far have always ‘heard’ back the same voice in my head, telling me the answer.

The answer that the voice in my head tells me, is three things:-

  1. Property
  2. Adventure
  3. Travel

I am happy and motivated when at least one of the three above motivations are present.

My main long term career has been in teaching technical subjects.

On the face of it that may not sound like it fits in with any of my three motivations (passions), but teaching can provide both adventure and travel. This is why my teaching career has been so successful.

I have also been involved in Bulgarian property investment, which ticks all three motivations, as there was the buying and selling of property.

There was also the adventure of traveling to a new country, and experiencing a new culture, including staying in ordinary Bulgarians houses.

Successfully Buying and selling property, setting up bank accounts and learning the language were also amazing experiences.

What Motivates You Then?

Have you asked yourself what motivates you?

In this culture, we are told in radio adverts and the media, that we are busy.

I know people who actually feel guilty if they aren’t constantly busy and doing things.

Its true that we are always doing something, but taking time to relax and listen to your inner quiet voice is surely worthwhile.

As I previously said, I asked myself what motivates me, and got the answer back, from my quiet inner voice.

Why not try it for yourself.

Just ask yourself the question over a few weeks, and listen to the answer.

For me it has been worthwhile, as I now have a decision template, that I can check new potential decisions against.

These are my ideas, and you may have other (even better) ideas, so get in touch and share.

 

Design Process When Designing Products

Product Design Process

The product design process can be applied to any product type.

Brief

In the initial stages a brief will be produced.

The brief is basically what you want the product design to achieve.

For example when I worked in the Space Industry, our core product was military defence satellites

Without giving away UK or NATO secrets, the product was a satellite that was launched into a geosynchronous orbit, to provide secure communications.

Therefore the basic ‘Brief’ document detailed an outline of what the system should actually do.

Research

The Second stage in the design process is research.

Is the product feasible and viable.

Does the technology exist, to be able to make the product brief a reality.

Another consideration is whether there is consumer demand for the product design.

Market research can help companies understand consumer tastes and attitudes to a product design.

Product Specification

Once research has proved that there is demand and the ability to produce the product, then the specification is drawn up.

The specification contains detailed information about the product to be produced.

Examples of the information include dimensions, materials, electrical performance etc.

Obviously the specification will change with every individual product that is designed.

Therefore not all specifications will contain exactly the same types of information. A plastic doll, may not contain electronics, so will have no ‘operating voltage’.

Brief

Research

Specification

Plan

Design

Test

Evaluate

Zigbee

Zigbee

  • Developed by Zigbee Alliance
  • IEEE 802.15.4 based specification
  • High level communication protocols
  • Used to create Personal Area Networks (PAN)
  • Uses small low power digital radios
  • Typically used for home automation, medical device data collection, other projects requiring low power & low bandwidth
  • Conceived in 1995, standardised in 2003, revised in 2006

Features of Zigbee

  • Low power
  • Low data rate
  • Close proximity data communications
  • Wireless ‘ad hoc’ network (WANET), which is a decentralised type of wireless network.

Zigbee Advantages (compared with other WPANS, such as Bluetooth & WIFI)

  • Simpler
  • Less expenditure

Zigbee Applications (typical uses)

  • Wireless light switches
  • Home energy monitors
  • Traffic management systems
  • Other consumer & industrial equipment, requiring short communication range & low wireless data transmission rate
Typical Zigbee Performance
  • 10 – 100 meters range (per device), based on line of sight
  • Range dependent on both power output & environmental characteristics
  • Long distance communication possible by passing data through a ‘mesh network’, which allows the data to transfer through ‘intermediate’ devices between zigbee nodes
  • Long battery life, due to low power consumption
  • Secure communication using 128 bit symmetric encryption keys
  • 250 kbit/s, which is suited to intermittent data transmissions, such as from a sensor or other input device.

 

 

 

Washing Machine Repair Fault Finding

Washing Machine Repair Fault Finding

Last Sunday while our Washing Machine was going through its washing cycle, the electrics tripped.

The first thing I tried was to reset the RCD, but it would not reset.

This was because a ‘leakage’ fault between the ‘line’ wire and the earth connection still existed.

So it was time for my fault finding skills to be put into practice.

There are various strategies that can be used to fault find electrical machinery, and I used to teach marine industry trainee electro-technical officers (ETO), how to do this.

The fault that was immediately visible, was that the mains RCD on the house Consumer Unit kept tripping as soon as the power to the machine was turned on.

Therefore the first thing I did was a visual inspection, inside the machine, after removing part of the outer casing (power was of course isolated first).

Carrying out visual inspections of a system is a good first way to proceed with fault finding, though it can be potentially dangerous, if you are unqualified.

The main reason that taking the casing off a washing machine could be potentially dangerous, is the Capacitor.

The capacitor is a component capable of storing electrical charge for a period of time, even after the power supply has been isolated (disconnected).

Therefore a nasty electric shock could result, if the connections were touched.

The results of my visual inspection of the machine components were that everything looked correct.

What I was looking for were any apparent loose connections, that could be causing a short circuit, or any signs of burn marks on components.

Washing machines contain both a heating element, and a Single Phase Induction Motor, which could be causing the short between the Line (live) phase, and Earth.

Two pieces of test equipment are used to test  the heater element, and the Induction Motor. These are a Multimeter,  and a Insulation Resistance Meter.

Unfortunately despite formally teaching people on a daily basis how to fault find using an Insulation Resistance Meter, I did not have one available.

Therefore armed with only a multimeter, I needed to use the other fault finding tool available, my Brain!

By asking questions of the person who had used the washing machine, before it went wrong, I gained clues as to the possible fault.

The machine had started ok, and run for a few minutes before tripping the electrics.

This clue helped me make an educated guess that the heating element might be at fault.

My reasoning for this ‘guess’ was that the washing machine cycle had already operated the water pump, to fill the machine with water. The Induction Motor that spins the drum had also worked before the fault appeared.

This in my mind at least eliminated the water pump, as it was not being used when the fault happened.

The Induction Motor on inspection did not have any apparent water that had leaked onto its Stator Coils, which might have caused the Insulation Resistance to lower, and hence trip the mains RCD.

Although without carrying an Insulation Resistance check on the Induction Motor, I could not be 100% sure that the Induction Motor was not causing the fault, I was ‘betting’ on the heater element, based on where in the washing cycle the fault occurred.

The first thing to do when testing the heater element, was to be totally sure that there was no electricity going to it.

I learned the importance of electrical safety at an early age (Age 11), when I forgot to turn off the mains supply, when wiring up an old analogue cooker clock, which I had ‘liberated’ from my parents old cooker.

As you can tell, I survived the shock, but still have three small burn scars on my hands, even today.

To ensure the electrical supply was off, I both checked the plug was removed, and also checked it with the multimeter, set to AC voltage.

Checking with a multimeter when the plug is out may sound overkill, but its something I do automatically, as a second check, in case I have forgotten to check the plug.

The two heater element Spade connectors were pulled off with the gentle help of a flat blade Screwdriver, and a Continuity Resistance check was carried out, across the two terminals.

The resistance shown was within the normal range, so would appear ok.

I still however suspected that there was a short inside the element, between the element wire, and the metal end. This would be caused due to internal resistance breakdown.

Without access to an Insulation Resistance (IR) tester I could not test between the two  connections, and the elements earthed metal plate.

Therefore I employed another fault finding strategy, which was to test the machine, with the heater element disconnected.

The two connection wires were disconnected, and insulation tape temporarily put on them, to eliminate the risk of the wires shorting to the washing machine casing, or together.

The machine was then powered up, and it ran successfully without tripping the mains RCD.

This had proved that the Induction Motor and Pump were working ok, and that the fault was with the heater element.

A replacement heater element was purchased, and fitted, resulting in a repaired and working machine.

LoRaWAN architecture and uses in Sensing

Lora-wan architecture

LoraWAN architecture is a narrowband wireless communications technology.

It is commonly used in the Internet of Things (IOT), to transmit data from remotely located sensors (known as sensor nodes).

Data from the sensors is then received by what is known as the ‘Gateway’.

The Gateway is a device that receives the data from the sensors, and puts it onto the Internet.

Once on the internet the data can be analysed and used to make automatic decisions.

An example of such an automatic decision might be to turn off a water irrigation system, because the fields are becoming too wet.

LoraWAN transmits small amounts of data (a few bytes at a time), at a slow rate.

Therefore you couldn’t use LoraWAN architecture for streaming live video, as the data could not be transmitted fast enough.

LoraWAN networks are being installed all over the world, both private and public.

The best known public LoraWAN network is the Things Network

The Things Network is a crownfunded IOT Internet of Things Network, that originated in Amsterdam, Holland.

It has rapidly expanded since 2015, and is now worldwide.

Our local Lincoln Things Network group was initiated by myself in 2016.

We have two Gateways and five members currently.

Private LoraWAN networks are also being installed by companies.

LoraWAN can be installed locally, with the software on internal company servers.

Alternatively LoraWAN can be based in the Internet cloud.

The advantage of hosting a LoraWAN server in the Cloud, is that data can be accessed easily from anywhere.

A number of companies are now springing up providing integration services using LoraWAN technology.

In fact some countries also now have national networks, providing the ability to gather sensor data from around the country.

Topics this artcile will now cover:

  • LoraWAN architecture overview
  • LoRaWAN network server
  • Device classes
  • Scalability
  • Uplink and downlink messages

Satellite Dish Installation Tips

Satellite Dish Installation Tips

Installing a satellite dish at your home or business premises is not as difficult than you might think.

This article is focused on installation of satellite dishes receiving television signals from Geostationary Satellites.

Satellite System Components

To receive television signals from a satellite, you will need:-

  • A satellite dish
  • An LNB (Low Noise Block)
  • A DVB Digital Satellite receiver
  • Suitable coaxial cable, to connect from the dish to the receiver box
  • 2 x ‘F’ Connectors, for each end of the coaxial cable.
  • A Satellite signal meter
  • Self Amalgamating tape (stretchy rubber tape for sealing cable ends against moisture)
  • Spanners, of appropriate size for adjusting the dish angle, and other tools, such as a Spirit Level.
  • A Compass.

The first step is to fit the satellite bracket to the dish, the dish will come with specific assembly instructions.

Once assembled, you next need to fit the LNB.

The LNB is the small circular plastic box that fits onto the end of the arm that sticks out in front of the satellite dish.

You will notice that the LNB has markings on it for angle adjustment. This is known as the ‘Skew’ angle, and is adjusted for optimal signal reception.

To know which Skew angle you require for your location, and the satellite you wish to receive, use a website such as  www.dishpointer.com

Attach the dish bracket to the wall, using a spirit level, to ensure it is vertical.

Before you start drilling holes in your wall, you need to ascertain the correct direction to point your dish.

For example, if you wish to receive Satellite ‘Astra 19.2E ‘, then you will need to point it in an easterly direction (hence the ‘E’ in the satellite name).

Using websites such as www.dishpointer.com will give you the information you need, so that you can use a compass to point the dish in the correct direction.

Satellite signals do not like obstacles such as trees and tall buildings in the ‘line of sight’ of the dish.

Obstacles need to be taken into account, so that the dish is positioned on the building, to give a clear (ideally) unobstructed line of sight to the sky.

Once you have attached the dish bracket to a suitable external wall (or temporary installation, as in photo), you need to set the correct elevation angle.

The Elevation angle details can be found on websites, and the dishes usually have angle markings on the bracket adjuster.

Once the elevation angle has been set, the Azimuth (rotation) angle must be set.  Again this information is available online, and you can use a direction Compass to point the dish roughly in the correct direction.

Next, connect up the coaxial cable from the satellite receiver box to a ‘Sat Finder’ device. These are cheaply available for less than £20.

The other connection on the Sat Finder (marked to LNB), is connected to the LNB on the dish.

Now once your cable is connected, switch on the power to the Satellite receiver, and turn up the sensitivity control on the ‘Sat Finder’ device.

You should hear a squeal sound as the dish is slowly rotated left and right.

Keep the dish pointed, so that you hear the squeal sound, and turn down the sensitivity of the Sat Finder, using the rotary control knob. Set it so that the needle on the meter is reading about half way.

Slowly move the dish left and right, until the strongest signal is recorded on the meter.

You can also try slightly adjusting the elavation angle (that you set earlier), to get the strongest signal.

Once you have the strongest signal, tighten the dish in that position, and turn off the power to the satellite receiver.

Remove the Sat Finder device from between the satellite cable and the LNB, and connect the satellite coaxial cable directly to the LNB.

Using Self Amalgamating tape, stretch around where the cable connects to the LNB, so help prevent  moisture entering the cable and connection.

Finally switch on the Satellite receiver and scan for satellite channels (see receiver instruction booklet).

You should now have satellite tv channels.

 

Note: This is a fairly basic set of instructions, and I will aim to expand them, when I get time in the future.

In the meantime , contact me if you wish to ask a question.

 

 

 

 

 

 

MQTT

What is MQTT Used For in IOT?

MQTT is short for MQ Telemetry Transport, and is a messaging protocol used in the Internet Of Things (IOT) systems.

It is very simple and lightweight messaging protocol, designed for devices with limited processing power and low-bandwidth, high-latency or unreliable networks.

MQTT was designed to minimise network bandwidth and device resource requirements, whilst also attempting to ensure data delivery reliability and some degree of assurance of delivery.

The MQTT protocol ideal for Internet of things (IOT) “machine-to-machine” (M2M) devices.

This is because bandwidth and battery power are at a premium, in IOT equipment designs.

Sensors for the Internet of Things – a guide

Sensors for the Internet of Things – a guide

Sensors are one of three main components of an Internet of Things, or IOT for short, system.

The first stage in an IOT system, are the sensors, which collect the environmental data.

Using automatic IOT Sensors , not only saves employing staff to manually take readings, but can also be safer in dangerous environments.

Choosing the right  sensors

The type of sensors that you need in order to automate your business operations, not only depends on the processes you wish to monitor, but also the environment that the sensors will be operating in.

Sensors for Damp Environments

Sensors situated in damp environments, whether actually immersed in water, or just located in a damp environment, require appropriate IP.

IP is short for Ingress protection, and is an internationally used rating system for how well a device resists ingress of dust and moisture.

Failure to chose a suitable IP rated sensor can result in premature device failure, causing increased variable maintenance costs for your business. We avoid this by planning a system that is reliable, and meets your business needs.

Sensor types and applications

A sensor is defined as a  Converter that measures a physical quantity and converts it into a signal.

Some examples of sensors that can be integrated by yesway, into your IOT system, are given below.

Airflow

Airflow is the amount of air passing through a pipe, for instance, over a period of time.

Airflow can be measured by a sensing device, which is integrated into a remote wireless node.

The data captured, is wirelessly sent back to an IOT Gateway device, which then sends it into the Internet Cloud.

Current

Current is defined as a flow of electricity which results from the ordered directional movement of electrically charged particles.

Measuring Current can be useful in Industrial Internet Of Things, IIOT environments, such as Smart Factories.

An example of an industrial machine that you may wish to monitor the current of, is the Induction Motor.

An Induction Motor is a type of electrical motor, widely used in factories, and on board ships.

The Induction Motor runs on Alternating Current (AC), and is available as both ‘Single-Phase’, or more typically ‘Three-Phase’ versions.

A Three-Phase Induction Motor has three supply wires (hence the name), which supply electricity along each of the three ‘phase’ wires.

Each Phase is 120 degrees apart, if you were to look at their Sine waves.

Measuring the Current being drawn by the Induction Motor, down each of the three phase wires, can help identify faults with the Induction Motor, or associated control systems.

Craig Miles (me), who founded our business has lots of experience in manual fault finding of Industrial Induction Motors, and even taught it to International Students.

Why not use our in-house experience to improve your factory operations, by integrating Sensors, to turn your factory into a Smart Factory.

Force

Pushing or pulling forces can be measured using wireless technology sensing.

These include forces being exerted on structures, such as bridges.

Humidity

Humidity levels can be measured, either as a standalone task, or as part of a Smart City integration.

Humidity measurement is useful, both in an external and internal environment.

Yesway have the ability to engineer a custom solution (if needed), to reliably operate within harsh, or explosive (ATEX) environments.

Thermal

Thermal heat levels can be measured, and fed to the cloud, where they can be plotted and analysed.

Magnetic

Magnetic sensors are found in applications, such as security systems, where they act as door sensors.

More sophisticated magnetic sensors, are capable of detecting varying magnetic fields.

Other Sensing Abilities

We can integrate many other types of sensing device, and wirelessly get your data onto the cloud.

Below are some more examples of sensors available.

  • Motion & Position
  • Optical
  • Pressure Sense & Transducers
  • Speed Sensors

Written and Copyright (C) Craig Miles 2018. Originally written for Yesway Ltd

What Is Industry 4.0

Industry 4.0

Industry 4.0 is a phrase that you will increasing hear in business manufacturing, but what exactly is it?

According to Wikipedia it is the following:-

“Industry 4.0 is the current trend of automation and data exchange in manufacturing technologies. It includes cyber-physical systems, the Internet of things and cloud computing. Industry 4.0 creates what has been called a “smart factory”. (Source: Wikipedia.com)

Why 4.0?

Industry 4.0 is often described as the Forth Industrial Revolution, so it would be useful to explain what Industry 1,2 & 3 were.

Industry 1.0

Industry 1.0 refers to the first industrial revolution that started around 1780.

The first industrial revolution was powered by water and steam, and was very mechanical in nature.

Industry 2.0

In 1870 the first electrically powered assembly line was introduced, and as the distribution of electricity become widespread, it opened up further opportunities for manufacturing.

This was the start of the era of mass production.

Industry 3.0

From the late 1960s onwards , computerisation started to be introduced into industrial processes.

This started with the Modicon 084 , which was the first PLC, which is short for Programmable Logic Controller.

A PLC is basically an industrial computer, used to control production processes.

By using PLC control, factories were able to improve efficiency, and save time and money.

An example of how a PLC did (and still does) save money is  that the program software can be easily changed and modified, to adapt to manufacturing requirements.

Prior to PLC control, you would need to redesign, and rewire large parts of your factory plant, to carry out the new process.  This was both time consuming , and expensive to do.

Industry 4.0

The latest revolution in manufacturing involves  minimal intervention & involvement by human beings.

Instead what is often described as ‘machine learning’ takes place, where algorithms make decisions based on live input data.

(c) Craig Miles 2018, all rights reserved

Originally written for Yesway Ltd