05.04.2019 12:21
Parent Category: Projects
Category: Automation
Views: 645

Why is a transformer needed in a pulsed electrical energy converter? Part 1

Alexander Rusu, Odessa

There are a lot of pulse converter circuits for electrical energy. Step-down, step-up, inverting, forward, flyback, with the output of the middle point of the transformer (Push-Pull), half-bridge, bridge and even “skew-bridge” (two-transistor) - even an experienced specialist can easily get lost and “drown” in them, not to mention beginners Moreover, they all solve the same problem - converting voltage of one value into one or more voltages of another level. In addition, sometimes they also provide galvanic isolation - electrical isolation input circuits from the weekend. But why so many schemes? Can't you come up with one? universal solution, which could be used in any situation?

Cyclic timers themselves can find application in the most different devices automation, be it periodic turning on of fans to ventilate the room, turning on indoor quartz lamps for air disinfection, etc. This entire continuous cycle with a certain ratio of work/pause time intervals can last for several days.

In this article I want to look at the operation of two such automation circuits for cyclic switching on an electric motor in a honey creaming installation.

In short, why is this necessary? Over time, honey is subject to crystallization and becomes hard, and in order for honey to reach the consumer in a less solid state and be more plastic, it is subjected to a technological procedure called “creaming.” The honey is placed in a container, where the blades mechanically mix it at a certain speed and cyclicity, for example: the blades rotate for 15 minutes, mixing the honey, and then there is a 15-minute pause, and so on in an endless cycle. It is not easy to assemble such an automation circuit on a microcontroller. special labor, but not for radio amateurs who have not yet mastered microcontrollers. To make assembly easier for beginner radio amateurs, I offer 2 options without the use of programmers and without microcontrollers.

Heating using waste oil is now gaining popularity and those who have access to waste oil are actively installing furnaces and boilers for waste oil. And those who don’t have access buy labor for pennies. (chapter )

But we're not talking about prices).

In this article I will tell you how quickly, in an hour to an hour and a half, you can assemble a primitive “automation” for a waste oil boiler.

It is difficult to call this device automatic; it does not switch to different modes, but serves to adjust the speed of the fan blowing air into the combustion chamber and the speed of the oil pump.

Below is a test circuit assembled on a table) It all came together in a couple of hours (including a trip to auto stores). And this is a temporary solution to maintain the operation of the boiler while we are developing the main automation.

I’ll describe a little how everything works and what it consists of.

The main two units that need to be controlled are the oil pump drive (it is the motor from the car window lifter) and the cochlea - the air blower. We need to control the speed of the scroll and the oil pump to increase/decrease the oil supply to the combustion chamber, and accordingly the air supply.

Required components:

Air blowing snail (can be used from a VAZ stove)
Oil pump drive and the oil pump itself (gear)
12V power supply
Fan for cooling automation
Oven speed switch (from VAZ) - 3 positions
Resistor (resistance) with the same 3 positions
Rheostat from a car (I don’t know exactly, it seems to be for adjusting the interior lighting)
Wires
Clamps mom / dad
A box for it all

The circuit is assembled

How it all works and is put together

The system has 3 modes rpm (stove speed switch): minimum, average and maximum.

Power from the 12 Volt unit goes to the mode switch, then to a resistor (resistance) with the same positions 1/2/3. From terminal 3 on the switch and on the resistor, wires go to the air volute and to an additional resistor (rheostat). The inflation volute has 3 speeds, as I already said, and the oil pump has the same 3 speeds. BUT power goes to the oil pump through a rheostat - pay attention to the photo - the red wire goes to the volute and terminals.

Thus, for the oil pump, each of the 3 modes has the ability to additionally adjust the speed of rotation with a rheostat, which allows you to very accurately dose the supply of used oil to the furnace.

The video below shows the diagram in action, but for now, detailed photos

18 ohm rheostat for smooth reduction of oil pump speed

Position switch 1/2/3 + terminal "+"

Switch internals. To mount it in the box, I had to disassemble the switch, drill holes in it and screw in screws.

The wires from the position switch go to their own 1/2/3 terminals on the resistance. The resistance heats up)))

Connection diagram for switch, resistor and motor

44 – fan motor
45 - additional resistor (used to regulate the speed of the electric motor, number 44)
46- position switch

Engine for oil pump

After I ran the entire system for a couple of hours on the stand “on the table,” I assembled everything and it turned out neat and beautiful.

To prevent the resistance from getting red hot, I installed a 12V fan into the box. Cools well

I started to worry about turning the buttons. the automation is temporary))) although the knobs can be made from polymophrus. But at that time it was 3 o’clock in the morning, and I had to leave in 4 hours, and during this time I would get some sleep... I decided to leave it as it was)

This is the boiler.

I tried to show how you can quickly assemble with your own hands a device for regulating the supply of oil and air into the combustion chamber of a waste oil boiler.

I ask those who are interested in this topic to unsubscribe in the comments, criticize, discuss and advise both me and everyone who is interested in the topic of heating during testing!

P.S.: we are currently developing automation with temperature sensors, program control and different combustion and protection modes for boilers and heaters during testing.

See about furnaces and boilers during mining in the section

UPDATE 01/18/2016: The boiler with this automation has been working continuously for 3 days at a car service center. Everything is stable. It warms up wonderfully. The most important thing is to rehearse the oil supply

Automation for a submersible pump

Having drilled a well for water summer cottage, usually, they begin to arrange it, because the water needs to be raised from the depths and supplied to the house. But it’s not enough to just let her down, you need to put together a system automatic water supply and configure it correctly. Its service life, as well as the service life of the deep-well pump, depend on the setting. You may not know, but often a well pump fails due to malfunctioning automation.

All installations and settings are carried out by specialists from the drilling organization and you, as to an ordinary summer resident, you don't have to waste time on this. But if you are interested in knowing how automation works for a well with a submersible pump, whether a hydraulic accumulator is needed, what are the reasons for system failures, etc., then now we will tell you everything.

Automation for a pump with a hydraulic accumulator

The most common option for pump automation is with a hydraulic accumulator because it does not require large financial costs and completely solves the water supply issue. A hydraulic accumulator tank is a container with a rubber membrane inside; this tank is placed in a caisson or in a house.
The automation diagram for a well with a hydraulic accumulator looks like this: the pump pumps water from the well into the hydraulic tank, thereby stretching the membrane until the pressure rises to a predetermined value, then the pressure switch opens the contacts and the pump turns off. Next, water withdrawal began, the pressure in the system begins to drop, but the pump is turned off. As soon as the pressure drops below a preset level, the pressure switch closes the contacts and the pump starts pumping water again.
And so on ad infinitum.

Need space for a hydraulic accumulator tank.

Membrane tank 100 l or 50 liters

The most popular hydraulic tank volume is 100 liters, but there are also more compact ones - 50 liters. Some summer residents refuse to install a 100 liter hydraulic accumulator tank because 50 liters seems to them to be a sufficient volume. Let's find out which is better membrane tank per 100 liters:

Since a rubber membrane is installed in the tank, which contains water, and air behind the membrane, the useful volume of the tank is a maximum of 70%.
Of this 70%, the tank cannot release all the water, because it needs to maintain pressure in the system. It will allow the pressure to drop, for example, by 1 atm, and this can be about 30 liters.
The larger the volume of the hydraulic accumulator tank, the less often it will turn on. submersible pump for pumping water, which means your pump will last longer.

Automation for a pump without a hydraulic accumulator

You can build automation without a hydraulic accumulator, but for this you need submersible pump with frequency converter. In such cases, they still install a small 5-liter tank so that water flows immediately after opening the tap because the pump has delays when turned on, even if only for a second.
Ordinary deep well pump can be either turned on or off, while a pump with a frequency converter can adapt to the current water consumption and produce more or. By opening the tap, the pump will turn on and pump water; by opening 2 taps, it will pump harder, and so on, until it reaches its maximum capabilities.
A striking example of such a pump is the Grundfos SQE, as well as three-phase pumps, for which you can buy a control unit with a frequency converter.

There is no need to install a hydraulic accumulator tank.

The price of a pump with a frequency converter is significantly higher.

Automation for low well production

Sometimes there are wells whose flow rate is not enough to provide the house with water, and to get out of this situation, you need to install a large water container somewhere in the basement. In this case, the automatic water supply system will work not according to pressure, but according to level.
The scheme of its operation looks like this: a well pump pumps water into a container, and there is a float in it, when the float rises to established level, it will close the contacts and send a signal to the control unit, which will turn off the pump.
The same thing in reverse side: the water level has dropped to the set value, a signal is sent to the control unit and the deep pump is turned on. It's simple.

Instead of a float, lower and upper electrodes can be used. As soon as water floods the upper electrode, it sends a signal to the control unit, which turns off the submersible pump. The same is true in the opposite direction: the level has dropped below the second electrode, the control unit turns on the well pump.
The second pump will pump water from the container into the system.

Well receiver

Probably the worst solution would be to use a container of water somewhere in the attic, in the form of a kind of receiver. It will stand at a height of 3 meters from the tap, and the water pressure will be 0.3 atm. No equipment will work, and you won’t be able to use water normally. To keep the pressure in order, you need to install the Rozhnovsky water tower at a height of 20-30 meters. Naturally, in a summer cottage in the Moscow region this is not feasible and there is no need for it.

Reasons for well automation failures

The automation must always be adjusted and monitored because the membrane pressure in the accumulator tank is released over time, through micro-cracks, through anything, but the pressure will inevitably drop. Then, the submersible pump with a hydraulic accumulator or something else begins to turn on frequently.
The drilling company prescribes a clause on the need for periodic maintenance of the system. But since it costs money, no one maintains anything, and they operate it until problems appear or the pump burns out.
Due to a system disorder, the pump may not turn on on time. For example, all the water had left the tank, but the submersible pump had not even turned on yet, and then the water stopped flowing. Then the pump turns on and refills the tank, at which time everything works normally until the water is completely drained from the tank again, and so on in a circle. That's why the water from well goes jerkily. Another reason for water surges is an incorrectly selected pump, the productivity of which is slightly greater than the flow rate of the well.
Also, after some time, the contacts on the pressure switch burn out due to constant switching and at one point it simply won’t turn on. The problem is resolved by replacing the pressure switch with the same new one.
If the automation is with a control unit, then there are many reasons and without specialists from service center It's better not to go there.

Automatic block
Advantages and disadvantages
Station diagrams
Location

A special flange is used to fix the rubber bulb to the body. Its design has an inlet pipe. Internal structure This tank is designed so that there is air between the membrane and the walls of the housing. It must be under a certain pressure, which is pumped into the chamber using a car or bicycle pump. This air not only helps maintain required pressure in the water supply system, but also counteracts overextension of the bulb into which water is pumped using a submersible pump from a well or well.

All hydraulic accumulators can be divided into several types:

units designed to work with cold water supply systems;
devices for hot water pipelines;
hydraulic expansion tanks for heating systems.

In our article we will look at the connection diagram and operating principle of a hydraulic tank for cold water supply systems. This tank is designed in such a way as to accumulate required volumes water and ensure the supply of liquid to water distribution points. Such equipment allows you to avoid water hammer and protect the well pump from frequent switching on.

Principle of operation

The operation diagram of the hydraulic tank after connecting it to the water supply system is as follows:

Using a submersible pump, water is pumped from a well or well into the rubber bulb of the tank.
As water is pumped in, the air pressure in the chamber between the walls of the housing and the rubber bulb increases due to the stretching of the membrane by water. When it reaches the maximum set on the relay, the contacts open and the pump turns off.
At the same time, you can continue to use water due to the fact that the membrane pushes it to the point with an open tap, household appliances or sanitary fixture. As the volume of liquid in the rubber bulb decreases, its walls put less pressure on the air in the chamber and the pressure gradually decreases. When it reaches the minimum set on the relay, the contacts close and the pump starts working again and pumping water from the well or well into the tank.
Then the cycle repeats.

Important: the frequency of starting well pumping equipment is directly related to the volume of the rubber bulb and the intensity of water consumption. That is, the volume of the tank must be selected taking into account the water needs of a particular family, so that the frequency of startup of the pumping unit does not increase, and this does not lead to its rapid wear.

Advantages of using a hydraulic tank

Thanks to the large capacity of the tank, you always have a supply of water, even if for some reason the water disappears from the source.
Using this equipment, you can maintain the required pressure in the water supply system, which will provide you with a uniform supply of liquid at all water distribution points.
The hydraulic tank reliably protects the system from water hammer.
The service life of pumping equipment is increased due to less frequent unit starts.
By injecting water into the pipeline, optimal conditions for work household appliances(washing machine and dishwasher).

Installation Features

well pump;
relay;
pipeline for supplying water from pumping equipment to the tank and from it to water collection points;
check valve;
shut-off valves;
filter device for rough cleaning water;
drainage into the sewer system.

Connection diagram to surface pump or pumping station looks much simpler because it's done block installation relay, that is, it is installed in conjunction with pumping equipment; there is also a built-in coarse filter and check valve.

Connecting the hydraulic accumulator

When connecting a hydraulic tank to submersible pumping equipment, a check valve must be used, which prevents water from flowing back into the supply pipeline and source after the pumping equipment is turned off. Otherwise, after turning off the pump, the air from the tank will squeeze water into the well.

The check valve is mounted on pump equipment before connecting all other elements of the water supply system. Further work is carried out in the following sequence:

First you need to properly install the submersible pump. To do this, you need to use a rope with a load to measure the depth of the well or well. After this, the wet spot on the rope can be used to determine the immersion depth of the pumping equipment.

Important: the well pump should be lowered below the water surface no more than 30 cm.

After the pump is lowered into the well, the cable on which it is attached is securely fixed to the surface at the head of the hydraulic structure.
After this, the hose or pipeline coming from the pumping unit on the surface is attached to the relay using a special fitting. This fitting must have five connectors.
After this, you need to connect the water supply system going into the house and the hydraulic tank to the connectors on the fitting. Also, a control device for the entire water supply system must be connected to another connector.

Attention: all connections must be carefully sealed using tow treated with sealant or FUM tape.

Now you can configure the relay.

Relay settings

For effective and proper operation hydraulic tank and the entire water supply system, the relay must be configured correctly. Since this unit usually comes with factory settings, this is done in the following sequence:

If there is water in the system, it must be drained by opening the bottom tap.
Now you can open the cover on the relay and turn on the pump to pump water.
At the moment the pumping equipment is turned off, you need to take the pressure gauge readings and write them down.
After this, open the most remote tap in the system and wait for the pumping equipment to start again after a certain amount of water has flowed out. At this moment, record the pressure gauge readings and write them down. Now we find the difference by subtracting from more smaller value. It should be equal to 1.4 bar. If your indicator is lower, you need to tighten the nut installed on the small spring more tightly. If the found number is greater, this nut must be loosened.
Moreover, if at the moment the water flows out of the most remote tap, you do not like the pressure, then you need to tighten the nut on the large spring after disconnecting the unit from the network. To make the pressure less, you need to loosen the nut on the contrary.
After the setup is completed, the system is launched and its effectiveness is checked. The setting can be repeated several times until you are completely satisfied with how the water supply system works.

Homemade products for children.

“Teach, tell”............ 5
We live in the age of automation........... 7
Before you get down to business.......... 10
For our little brothers.......... 12
What time is it?............ 16
Vehicle commanders........................ 22
How do machines “feel”......... 25
"More! Less! More!......... 33
And the machines need “muscles”.......... 34
Relay - what is it?............ 35
The time relay works............ 39
Red, yellow, green........... 45
Miracles of pneumonics......................... 50
This amazing top........... 52
From the sky on foot............... 59
In the depths of the seas and oceans........... 66
Wind and automation......................... 68
What's the weather like tomorrow?............ 76
Automation teaches................... 81
Machines that can count......... 88
Let's play with the machine......................... 99
Automated sellers........... 106
How robots learned to work.......... 112
In the world of “smart” technology............ 121

“Teach, tell”

Maybe you came across a book called “Journey to the Land of Robots.” I wrote this book several years ago. It talked about automation and that. what kind of machines there are and what they serve.

The book was published, and soon I began to receive letters from readers. Judging by the responses, the kids liked the book. Letters arrived from all over our country: from Moscow. Riga, Chelyabinsk, Krasnoyarsk. One boy even wrote from distant Chukotka.

“I really liked the book “Journey to the Land of Robots,” wrote from the city of Labinsk Krasnodar region Lena Shara-putinova. “Write a sequel to this book.”

Sasha Karyakin from the village of Turgoyak, Chelyabinsk region, also asked for the same thing. “I really like reading about technology, about space and about rockets,” he wrote. “Please continue.”

But most often the guys asked how to learn how to make various automations themselves. Almost every letter ended with questions: “How to make an automatic machine, automatic model or device? What materials should they be made from? Teach, tell."
Zhenya Zhitnov from the city of Omsk asked: “Advise how to make an automatic calculating machine. Maybe there is a book that talks about this?”

Kolya Ibragimov from Tatarstan asked to send drawings and a description of a simple robot. “I need,” wrote Kolya, “the dimensions of the parts. I would like to get the drawings as soon as possible because I want to start building during spring break.”

And again and again about the same thing. “Sasha Kulikov writes to you. I live in the 8th city of Arzamas. I'm in fourth grade. I am an average student. There are almost no twos. I liked the book, the only bad thing is that it doesn’t say anything about how you can make the automation yourself.”

There were also letters from several guys at once. “We want to know how to make models of machine guns,” said friends from the city of Kurgan Gleb, Oleg, Andrey, Seryozha and Tolya. And they signed it like this: “Orchimedes.”

The desire of the guys was clear to me. The book sparked their imagination. Automation is wonderful) But it was created by adults. I wish I could make a device that works automatically with my own hands! And not too complicated. Where can I get materials, expensive parts, different instruments? And there is still not enough knowledge. And I want to build! How to be?

A lot of letters arrived, several hundred. It was, of course, impossible to answer, help, or send drawings to all readers. And then I thought: “Really, why not write a new book in which not only continue the story about automation, but also teach children how to create simple machines with their own hands?”

Building models is not only interesting, but also very useful. I am sure that only by making the model yourself, you can clearly understand and firmly remember how a real machine works, automatic device, device.

When you become an adult, you will certainly deal with automation in one way or another: use it, set it up and configure it, or even create a new, unprecedented one. And the sooner you find out about what kind of machines exist in the world and how they work, the better. Then you will no longer look in surprise at the most complex, most ingenious machine, you will begin to work with it more confidently.
I hope that the book will help you understand the “ABC of Automation”, take your first steps in it, and become better acquainted with this very necessary and important area of technology.