What’s the best motor for a lawnmower?

A little bit of theory

Before you decide the problem of what to choose a lawn mower to work on your lawn, you should know that the electric motor in a lawn mower comes in two types:

• Synchronous. This is a motor in which the rotor and the magnetic field rotate at the same speed. synchronously. Even if the rotor is heavily loaded, the rotor speed is not reduced. The motor continues to run at a stable speed. To achieve this result, sliding contacts are used. Therefore, the synchronous motor is more complex in construction and therefore more expensive in cost.
• Asynchronous. Motor in which the rotor speed does not match the speed of the magnetic field. The stator and the rotor are separated by an air gap, there are no contact rings. It is simple in construction, which means that it is not as difficult or expensive to make as a synchronous motor.

What is the best lawnmower motor, it is impossible to answer unequivocally. Both types of motor have advantages and disadvantages.

For those who do not want to delve deeply into the wisdom of electromechanics, we will explain quite simply. Each motor has two key elements: the stator (immovable, with windings) and the rotor (movable). The current from the mains is fed to the stator. In its winding there is a magnetic field, which rotates. Thanks to it, the rotor starts to rotate as well. And already the rotor revolutions are transmitted to the shaft of the device.

In our case. on the vertical shaft, on which the cutting blade of the lawnmower is installed. So it turns out that the blade’s performance is directly related to the engine speed. Stable speeds mean that the blade rotates steadily and powerfully. Weak rotor revolutions. the blade begins to weaken, too, drags the grass. It simply has “no power” to cut vegetation quickly and accurately. If you define very briefly what is the best lawn mower, then let’s say:

But all this is a bit exaggerated, and in no way means that the induction motor is worse. Asynchronous motor. the simplest and cheapest of all previously invented. It doesn’t require complex maintenance, it doesn’t get very hot, it has no rubbing contacts. And its reliability is within the norm, if the manufacturer is good and has installed the safety systems.

Electric lawnmower with synchronous motor

The synchronous motor always runs at a constant speed. Because of this factor, it is used in places where a stable speed is essential. In lawnmowers, this point is neither pivotal nor necessary. Synchronism is even more important with a high motor power. In mowers, it’s more than 1 kW. The blade on synchronous mowers is mounted on a separate shaft. The shaft is connected to the motor shaft by a belt drive. The weak point is the blade shaft bearings.

• Low sensitivity to mains voltage fluctuations.
• Steady cutting blade rotation regardless of the load.
• High efficiency and power factor.
• Complicated design.
• Brushes are warmed by friction.
• Difficult to start. To make things easier, the rotor is started asynchronously before adjusting to the magnetic field.

Electric lawnmower with asynchronous motor

Induction motors are being used more and more frequently these days. In this case the blade is placed directly on the motor shaft. It turns out a simple and fairly reliable design. No rotor winding. No brushes. Nothing complicated, and everything works fine.

• Simple design. No maintenance. easy repair.
• Low manufacturing and maintenance costs.
• It gets less heat. Even if heated, it continues to work, losing speed.
• Efficiency and power factor are lower than synchronous motors.
• Speed is difficult to regulate. low controllability.
• The speed depends on the mains.
• Very sensitive to voltage fluctuations in the mains.

So, when choosing synchronous or asynchronous lawnmowers, you must be guided by considerations of either low cost, or decide which is more reliable in operation.

Selection criteria for the type of motor

Which lawnmower motor to choose?? The answer lies in the needs of the landlord. If a larger area is to be treated, a petrol-powered machine can do the job. Such a mower is mobile and maneuverable, has a high productivity. Disadvantages of the model include:

• High noise level;
• High weight of the machine;
• Pollution of the environment by exhaust gases;
• High cost;
• Dependence on quality gasoline and oil.

If the area is small, you can improve it with a grass trimmer or an electric lawnmower. It is virtually silent, environmentally friendly and easy to handle. Among the minuses:

Interesting! If you opt for an electric mower, then you need to ask yourself what kind of engine it has. Lawn mowers with an asynchronous motor cost less than synchronous motors, but they are inferior to synchronous motors in terms of power. Such devices practically do not heat up, they are easy to maintain. On today’s market, the most common lawn mowers with an asynchronous motor and direct drive.

Top 3 petrol lawnmowers

VIKING MB 248

This semi-professional model can be used on plots of up to 1 hectare, the manufacturer recommends its use both on homestead plots and in the wooded area. In order to achieve the most efficient operation of the equipment, you should use the model on a flat lawn, where there are no bumps. This lawn mower easily cuts even quite thick grass. Powered by the latest BriggsStratton 405E Series engine, it delivers excellent quality and economy of operation. With 2.5 HP. с., Tank capacity. 0.9 l. That means it can go for a long time without refuelling The grass catcher box capacity is 55 liters, holds absolutely all mowed grass. The model does not weigh too much. only 27 kg, so it is easy to handle on its own, even load it into the car trunk.

One of the main advantages of this mower is its self-propelled nature. the device does not have to be pushed in front of you. Maneuverability is high, the model can easily turn at any angle on the spot, if necessary, the design can even be turned around. Mowing is very easy, it leaves a smooth lawn after treatment. The engine is a four-stroke, there are almost no exhaust fumes, because the fuel is burned almost completely. Practically no noise, collapsible model, takes up minimal space when stored.

• Increased cutting width. 51 cm;
• Easy to use;
• Not too heavy.

• No indicator that the gasoline in the tank is coming to an end.

Champion LM4215

This model is designed for home gardens up to one hectare. Users can mow in two mowing modes: mulch mowing or grass collection in a bin. Width of swath 42 cm. Five-position switch for cutting height. maximum 70 mm, minimum 25 mm. Engine output of 2 liters. с. With a displacement of 99 cc, the engine is easy to use. see. The internal combustion engine itself is four-stroke, has an air cooling system, does not overheat even in the strong heat. The grass catcher box is reliable, made of dustproof material, its volume is 40 liters. To work with this device does not require any additional skills.

Rear wheels are slightly larger than the front wheels, which increases maneuverability. This is not a self-propelled machine, so you will have to push it in front of you, good thing it does not weigh as much as other similar products. only 22 kg. During operation emits a small amount of noise, so it is allowed to use near residential buildings.

• For its engine volume is quite powerful;
• An easy start system is provided;
• Gasoline and oil are filled separately;
• Low noise level.

• It is difficult to maneuver between trees.

Makita PLM4620

This is another semi-professional model, which is quite acceptable for use in medium or small areas, such as cottage plots. The model is very functional, weighs relatively little, has excellent performance characteristics. This is a four-wheeled device of non-self-propelled type. It is based on a four-stroke carbureted engine with 3.4 L.с., The engine is started by a manual starter and the number of revolutions is regulated manually. Overheat protection is airborne. A special emergency stop lever is provided for the engine.

Casing made of stainless steel, 1.5 mm thick. Plastic wheels with non-slip bearing. Rear ones are larger in diameter than the front ones. The model can be folded up for transportation. Grass catcher bag is textile, with plastic lid. The grass is cut with 4Cut technology, the mulching function can be activated.

How to choose

Specialist retailers offer a wide selection of units. Professionals recommend paying attention to such popular manufacturers as Lifan, Patriot, DDE, Mitsubishi, Honda. A self-propelled lawnmower requires the most powerful motor. If the time has come to replace the motor in an older model, discontinued from production, you need to review the compatibility of equipment with other brands.

Every year a rating of quality products from the world’s leading manufacturers is published, companies acquaint their admirers with the latest garden equipment produced. Where to buy? It is desirable to buy in specialized stores. The manager will help you decide on the choice, pick up the product with the necessary function, tell you how much it costs. There is an option to order a unit in the online. store, making an application online. But beforehand you need to decide on the model, read reviews about it, study the rating of suitable products, carefully read the characteristics and capabilities, decide on the possibility of repairing it yourself in case of breakdown or failure of certain elements. The main disadvantage of this type of purchase. the possibility of getting a Chinese fake for a lot of money.

BS series 450 engine (9T602/0128) 3.5 л.с. for VIKING HB 445, 445R

This engine model belongs to the well-known 450 series of single-cylinder BriggsStratton engines, which are widely used on lawnmowers, cultivators and tillers. One of the great advantages of the 450 series engines is their low tolerance for fuel quality. You can easily fill the engine with A-92 gasoline.

BS 450 Series Engine (9T602/0128) 3.5 л.с. For VIKING HB 445, 445R

BriggsStratton 675 EXi Engine Art. 104M020066H5

The 675 EXi engine is lightweight, making it easy to operate the tool. Engine has ReadyStart function for easy starting. The special design of the engine allows maintenance without tools. also a big plus.

BriggsStratton 675 EXi Engine Art. 104M020066H5

How a 2-stroke engine works

The essence of operation of any internal combustion engine is that it repeats the same type of cycles. Each of these consists of the fuel entering the cylinder and then being squeezed by the movement of the piston. During compression, the fuel turns into gas, enters the gas chamber, and expands. It releases a large amount of thermal energy, which is converted into mechanical energy and turns the crankshaft a full turn.

So that’s the cycle. The movement of the piston plays a significant role. up and down, because that’s what the compression ratio depends on. This piston stroke is called the stroke.

In two-stroke engines, the piston takes two strokes. A fuel mixture (gasoline mixed with oil) is used as fuel. The mixture is prepared before filling, in this mixed form it enters the combustion chamber, which gives a very specific smoke at work of the two-stroke motor. It’s just the oil that’s burning. But this 2-stroke engine doesn’t need any oil refill because the brushcutter gears draw their oil directly from the combustion chamber.