Electric Motor From Lawn Mowers Where To Apply
Electric lawn mower. Not the simplest equipment, and if it is not purchased by a specialist (that is, not an electrician), then he is unlikely to be interested in the question of what type of engine is installed in it. The problem becomes relevant only when the engine begins to "junk". Accordingly, it requires attention. He can:
- Overheat and shut down.
- Do not “pull” in power.
- Just burn out (worst case scenario).
In any of these cases, the user begins to repair or replace the engine, and then, finally, he finds out what kind of electric motor his equipment has.
In order to save you from such unpleasant moments, we picked up advice on which electric motor for lawn mowers to choose, taking into account their capabilities and needs.
Bit of theory
Before solving the problem of choosing a lawn mower to work on your lawn, you should know that there are two types of electric motors for a lawn mower:
- Synchronous. This is a motor in which the rotor and magnetic field rotate at the same speed – synchronously. Even if the rotor receives a heavy load during operation, its speed does not decrease. The engine continues to run at stable speeds. To achieve this result, sliding contacts are used. Therefore, a synchronous motor is more complex in design, and therefore more expensive at cost.
- Asynchronous. An engine in which the rotor speed does not match the speed of the magnetic field. The stator and rotor are separated by an air gap, there are no slip rings. It is simple in structure, which means that it is not as difficult and expensive to make it as synchronous.
Which motor of the lawnmower is better cannot be answered unequivocally. Both types of engines have their advantages and disadvantages.
For those who do not want to delve deeply into the wisdom of electromechanics, we explain very simply. Each motor has two key elements: a stator (immovable, with windings) and a rotor (movable). Current from the mains is supplied to the stator. A magnetic field appears in its winding, which rotates. Thanks to him, the rotor also begins to rotate. And already the rotor speed is transmitted to the device shaft.
In our case, on a vertical shaft on which a cutting knife of a lawn mower is mounted. It turns out that the operation of the knife directly depends on the engine speed. Stable revolutions – the knife also rotates stably and powerfully. Weak rotor speed – the knife also begins to weaken, tightens the grass. He simply has “no strength” to quickly and efficiently cut vegetation.
To determine very briefly which lawnmower is better, let’s say this:
But all this is a little exaggerated, and in no way means that the induction motor is worse. Asynchronous motor is the simplest and cheapest of all previously invented. It does not require complicated maintenance, does not heat up much, it does not have rubbing contacts. Yes, and its reliability is within normal limits, if the manufacturer is of high quality and has installed protective systems.
Synchronous Electric Lawn Mower
The synchronous motor always runs at a constant speed. Due to this factor, it is used where stable turns are especially needed. In lawn mowers, this moment is key and necessary. Also, synchronization is important with high engine power. In mowers, this is more than 1 kW. The knife in synchronized lawn mowers is placed on a separate shaft. This shaft is connected to the engine shaft by a belt drive. Weak point – knife shaft bearings.
- Low sensitivity to power surges.
- Stable rotation of the cutting knife, regardless of load.
- High efficiency and power factor.
- Sophisticated design.
- Brushes with friction are heated.
- Hard start. To facilitate this, the rotor is first started asynchronously, and then it is adjusted to the magnetic field.
Asynchronous Electric Lawn Mower
Currently, asynchronous motors in lawn mowers are used more and more often. In this case, the knife is placed directly on the motor shaft. It turns out a simple and fairly reliable design. There is no rotor winding. There are no brushes. Nothing complicated, and everything works fine.
- Simple construction. No maintenance needed. Easy repair.
- Low cost of manufacturing and operation.
- Heats less. Even if it heats up, it continues to work, losing momentum.
- Efficiency and power factor lower than that of a synchronous motor.
- It is difficult to regulate the speed of revolutions – low controllability.
- Turnovers are network dependent.
- Very sensitive to power surges in a stationary network.
Thus, when choosing synchronous or asynchronous lawn mowers, you should be guided by considerations of either low cost, or decide which is more reliable in operation.
Regular mowing stimulates the growth of new shoots and helps maintain an attractive lawn appearance. Manual haircuts are difficult, so some gardeners and homeowners have acquired lawn mowers. If the budget is limited, then you can make a functional device for mowing yourself. To create a lawn mower with your own hands, you will need parts of unnecessary equipment, inexpensive materials and a standard set of tools.
- The device and principle of operation of the lawn mower
- Principles of Designing a Homemade Mower
- Calculation of the type of engine and its power
- Optimal shape and material of the knife
- Installation housing and mowing shield
- Wheel dimensions and control knobs
The device and principle of operation of the lawn mower
The electric grass mower has a fairly simple device. The design consists of the main technological units:
- Power plant – an electric motor;
- Frames for fixing all working mechanisms and components;
- Knives and protective frames;
- Wheels providing movement of the device;
- Handles for management.
The engine is mounted on a platform with wheels. A cutting deck is installed from the bottom of the frame, and a control handle is attached to the side of the platform.
Unlike home-made lawn mowers, factory-made models are safer and more convenient. Many designs include a grass catcher, a set for mulching, an additional system for protecting against knife breakage, and the ability to adjust the cutting height and handle.
Electric mowers operate on a single principle. The engine drives the output shaft (feed sleeve), which in turn begins to rotate the cutting tool at high speed.
Principles of Designing a Homemade Mower
Before you make a lawn mower with your own hands, you need to evaluate the territory of the upcoming mowing – the area and the relief. The equipment power, working width and cutting height depend on these parameters.
Calculation of the type of engine and its power
For manufacturing, almost any serviceable engine from a power tool or household appliances is suitable: a washing machine, vacuum cleaner, drill, chainsaw or angle grinder. The best option is an asynchronous motor with a power of 500 watts or more, the speed of rotation is about 3,000 rpm.
In order to balance the indicators and overcome the increasing resistance, you will have to install a more powerful engine. For example, for mowing grass with a strip of 50 cm, a 1500 W electric motor suitable for 1500 rpm is suitable. A 500 W power mechanism will also cope with the work, however, to maintain normal quality of the bevel, you will have to sharpen the knives regularly.
Optimal shape and material of the knife
The simplest to manufacture, reliable and quite effective is considered to be a horizontal two-blade knife, the so-called propeller. You can make it one of the ways.
Method 1. One-piece cutter. The knife is cut from a strip of tool steel. Its length corresponds to the capture size of the mower (30-50 cm), and the width is about 20-50 mm. On the front side, sharpening is performed at an angle of 60 °, and the back is slightly bent. Propeller configuration ensures even laying of mowed grass.
Method 2. Combined knife. Two short cutters (60-80 mm each) are mounted on opposite sides of the mandrel at an angle of 180 ° relative to each other.
Video: Electric Motor From Lawn Mowers Where To Apply
To fix the pointed segments using one or two bolts. The first option is less reliable, but has a significant plus – when hit on a solid object, the cutter does not break, but folds.
Recommendations for making a knife:
- As a material, it is good to use a saw blade for wood or tool steel 2 mm thick;
- It is desirable to bend the cutting edges a little down – this will reduce the winding of vegetation on the engine shaft;
- The knife must have a clear centering, otherwise even a slight beating will lead to strong vibration and destroy the joints of the working nodes;
- The motor shaft should also be protected with a metal casing – a tin can can play its role.
Installation housing and mowing shield
The frame of the mower at the same time acts as a frame for the knife and the body on which all the parts are mounted. The simplest solution to the mowing shield is to use a prefabricated mold. For example, a shallow metal basin, a large pan, or the bottom of a pan. In the workpiece, it is enough to prepare a hole for installing the motor shaft.
If there are no suitable parts, then the frame and the frame for the knives will be made of steel corners or pipes. To create a platform, a board, dense plywood or a metal sheet 4 mm thick is suitable.
Wheel dimensions and control knobs
The size of the wheels depends on the terrain and the preferred height of the lawn. From the point of view of aesthetics, the optimal height of the “lawn” is 5-6 cm. If the size of the wheels is too large, the grass is cut unevenly, and the low landing of the platform makes it difficult for the mower to pass through the site.
The number of wheels is selected at the discretion of the wizard. It is important to take into account some nuances:
- Three- and four-wheel models are stable and provide the same mowing height;
- Two-wheeled mower is more maneuverable, which allows you to cut grass in hard to reach places;
- When manufacturing a two-wheel lawn mower, it is necessary to provide a frame that protects the knife from touching the ground;
- In three-wheeled units, two wheels are located on the side of the handle, and one on the front – this will facilitate the turn of the lawn mower.
The handle for the mower can be welded from a metal or water pipe with a diameter of about 3 cm, made from shanks of a shovel, removed from an old cart or stroller.
Homemade lawn mower from a washing machine
It is quite simple to make an electric lawn mower with your own hands from a washing machine. The budget option will cope with a lawn mowing up to 5 acres. The unit must not be overloaded during operation. The engine must be turned off periodically, allowing it to cool.
Preparation of tools and materials
To make a homemade device you will need:
- An electric motor from a washing machine, it is desirable to take an asynchronous one – such an engine is less noisy. Motors from Soviet-style equipment with a power of 200 W are suitable, which due to their heavy weight provide high stability and inertia.
- Switch from a semi-automatic washer.
- Strong wheels with a diameter of about 10 cm – they will be installed so that 5-6 cm remain to the ground.
- Tool steel strip – 5 cm thick, length dependent on mower grab.
- Metal sheet with dimensions of 3050 cm, thickness – 5 cm.
- Profile pipe for the manufacture of the handle.
- Sections of a steel corner for a frame.
- Three-core copper wire and plug. Cable length depends on the size of the site – it is better to take the size with a margin.
- Consumables: bolts, studs, nuts.
From the tools to prepare:
- Socket and open-end wrenches;
- Electric drill;
- Welding machine;
- Angle Grinder;
- Soldering iron;
- Measuring tools.
Step-by-step assembly instructions
Before you start making a lawn mower, it is advisable to develop a visual drawing indicating the main dimensions of the device:
- The full width of the mower, corresponding to the diameter of the frame for knives;
- Knife lengths;
- Mowing height and depth of mowing shield;
- Wheel diameter.
Detailed drawings of do-it-yourself mowers are shown below.
- Frame manufacture:
- Weld the frame from a metal corner;
- Open the platform for the installation of the engine and prepare a hole for the engine shaft in the workpiece;
- Weld struts for mounting wheels on both sides of the frame;
- Attach the platform to the body;
- Install an arc on the front side of the frame – this element will protect decorative plants from accidental mowing.
- Making a knife:
- On the metal strip draw the boundaries of the torch;
- Sharpen knife cutters;
- Make a hole clearly in the center of the part for mounting to the motor shaft.
- Handle preparation:
- Choose a convenient handle height – about 90 cm;
- Make a U-shaped handle from a metal pipe;
- Wrap the handle with insulating material (electrical tape or rubberized casing).
- Connection details:
- Install wheels on the sides of the platform;
- Weld the handle to the frame;
- Install the engine on the platform – place the shaft in the hole on the base of the mower;
- Attach a knife to the motor shaft – the cutter must be centered and balanced (the knife does not warp when scrolling);
- It is advisable to cover the engine with a protective casing with small holes to prevent overheating;
- Connect the cable to the motor, securing the cut with the plug and switch to the handle;
- Check connection points, cable integrity and test run.
Video: DIY Electric Lawn Mower
Alternative – chainsaw mower
Gasoline lawn mower has a higher productivity. The chainsaw model is capable of continuous operation for a long time. The design is almost the same as that of the electric counterpart, the only difference is the use of a fuel engine.
For such a mower, the motor from the Druzhba or Ural chainsaw is suitable. The first step is to make the frame, wheels and handle according to the technology described in the previous section. Further actions are performed in this order:
- Disconnect the tire and steering wheel from the chainsaw.
- Lock the control lever (steering wheel) on the handle.
- Extend the fuel hose and extend the adjustment cable with the carburetor throttle.
- Turn the gearbox with the engine 90 ° so that the engine shaft is located at the bottom.
Unlike a washing machine mower, you can’t just attach blades to the motor shaft. It is necessary to make a kind of nozzle from two pipes of different diameters. The algorithm for creating a working mowing unit:
- On a chain sprocket, weld a piece of pipe with a length of 8 cm and a diameter of 5 mm.
- Make a workpiece from the second pipe – length about 9 cm, diameter 13 mm.
- Place the large pipe on the narrow one and fasten the elements with bolts with locknuts. The result should be a telescopic system for adjusting the length.
- Drill holes along the length of the body to change the height of mowing the grass.
- Attach a metal disk 4 mm thick, 18 cm in diameter to the wide pipe by welding.
- From the hacksaw, cut three cutters 12 cm long, 3 cm wide.
- Attach the cutters to the disk with M6 bolts.
After fastening all the structural elements and refueling, you can start mowing the grass.
Video: Home-made chainsaw mower
Safety precautions for operating a homemade lawn mower
Regardless of the type of power device, a do-it-yourself lawn mower is a traumatic technique. There are several threats: injury by a rotating blade, impact by an object bouncing from under the mower, electric shock or fire in a fuel tank.
To minimize risks during operation, you should strictly adhere to safety rules:
- Perform grass mowing in closed shoes and long trousers. It is advisable to use glasses to protect the eyes from dust.
- Work to be carried out only in conditions of good visibility.
- Keep children and animals away from the unit. The danger zone radius is 30 m.
- It is forbidden to cut a wet lawn with an electric mower.
- If you need to go away, the engine must be disconnected.
- All parts can be cleaned or repaired only with the mechanism turned off and cooled.
- When upgrading a slope, moving the mower is necessary along the hill, and not up and down.
- Reverse and move along hard surfaces with the engine off.
For those who have some welding skills, an idea of the structure and principle of operation of the lawn mower, it will not be difficult to make such a technique yourself. However, you must act with extreme caution, because a minor error significantly increases the risk of injury.
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Lawn mower – This is a kind of gardening equipment designed for mowing grass in large areas. Lawn mowers come in two forms. Depending on whether there is an engine on this unit or not, they are divided into mechanical and motor. In turn, motor lawn mowers are divided into three types: cordless mowers, with an electric motor (manual and self-propelled electric lawn mowers) and with a gasoline engine.
For electric lawnmowers, the electric motor has a power of 0.8 to 2 kW. Such lawn mowers are used mainly for processing areas whose sizes do not exceed 8 acres. They are quite simple to operate and maintain, have small dimensions and weight. Due to this, they are easy to move and store. In addition, the Stiga, Gardena and Champion electric lawnmowers do not make much noise during operation.
However, along with many advantages, this unit has one drawback – it is network connectivity. During operation of this mower, you must always make sure that the network cable does not fall under its cutting system. That is why, when buying a lawn mower with an electric motor, you should pay attention to the fact that she has a network cable with a bright color.
When working with an electric lawnmower, certain precautions should be followed. Firstly, mowing the grass with this unit is necessary only in rubber shoes. Secondly, in no case should you use an electric lawnmower in wet and rainy weather.
The electric motor of a lawn mower is a rather complex device. It requires careful handling and certain care. Before you start working as an electric lawn mower, you must check the area to be treated for stones and other foreign objects that could harm both the lawn mower mechanism and the worker himself. If possible, all foreign objects from the site should be removed.
Speaking about the power of the electric motor of the lawn mower, it should be noted that the larger it is, the wider the working width. In addition, it should be noted that if the grass has grown more than 30 centimeters in the cultivated area, the electric lawn mower will not be able to cope with it, since its motor is not designed to work in such a volume. Therefore, to begin with, it will be necessary to process the site with an oblique or trimmer.
It should also be noted that when operating an electric lawnmower in the network to which it is connected, voltage surges can occur. Because of this, the engine of this unit can quickly fail. Therefore, when buying a lawn mower with an electric motor, you should also purchase a stabilizer or even purchase a gasoline lawn mower. For example, the Husqvarna lawnmower.
During continuous operation of an electric lawnmower, its engine may overheat. Therefore, after every 15-20 minutes of operation, this unit must be turned off and allowed to cool and rest for at least 5 minutes. Otherwise, a spontaneous shutdown of the engine may occur, i.E., the protective mechanism of the mower will work, which indicates that the engine is clearly overloaded.