# How to increase the speed of a circular saw. Calculation of pulley for toothed belt. Calculation of pulley revolutions, changing the belt transmission ratio.

## What power motor is needed for the circular saw

Here everything depends on the power of the machine. Belt-driven motors are best, so the RPM is transmitted directly to the saw. If you plan to install a 35 cm disc on the circular saw, it needs 1 kW power to start it up. The saw, the diameter of which is 17 cm, runs from 500 watts. This means that the motors from old washing machines Sibir or Oka will do. The only thing left is to adjust the engine speed, because unstable rotation will cause the saw to “tear” the wood.The tachodactor, which controls the control module, is responsible for the engine speed in the washing machine. But since the module will not connect to the circular, it is recommended to install a voltage regulator.

Connecting the electric motor is considered an important working step, and if you do not get it right, then you can not wait for the normal operation of the circular saw.

## Speeding up the induction motor to maximum rpm

See what happens. The motor is connected through a frequency converter. You can use a frequency converter to.

What happens to the motor and its load if the rated speed is exceeded? P700 inverter from.

The introduction of a resistance in the rotor circuit. The first two ways of adjusting the speed of rotation of asynchronous motors require either a special motor design or the presence of a special frequency converter, and therefore are not widely used. The third way to adjust the speed of rotation of induction motors is to introduce a resistance in the circuit of the rotor winding with a rheostat during the operation of the motor.

With increasing resistance in the rotor circuit, the value of slip S increases, which corresponds to a given value of torque M (the value of torque developed by the motor is equal to the resistance torque on the motor shaft). Thus, introducing an additional active resistance into the circuit of the phase rotor, we increase the slip S and, consequently, reduce the rotor speed n. How to increase the speed of an electric motor; How to increase the speed of an induction motor. This type of control is only suitable for induction motors with a phase-type rotor. A rheostat is connected to the rotor circuit in the same way as a rheostat for starting. The difference between a starting rheostat and a regulating rheostat is that the regulating rheostat is designed for long current flow. For motors with rotor speed control by changing the resistance in the rotor circuit, start rheostat and control rheostat are combined into a start rheostat. The disadvantage of this control method is that the larger the motor speed control is, the more power is lost in the rheostat.

Braking of asynchronous motors. Under operating conditions it is often necessary to brake a motor to accelerate its stopping.

Braking of electric motors can be mechanical, electrical and electromechanical. Electromechanical braking is performed by a belt or shoe brake acting on a brake pulley attached to the motor shaft. The belt or shoes are released by a braking electromagnet connected in parallel with the stator winding.

If any two phases are switched when the motor is running, the motor will begin to develop torque in the opposite direction. The rotation of the rotor slows down. When the speed of rotation is close to zero, you should unplug the motor, otherwise under the action of the torque it develops, it will begin to rotate in the opposite direction. There are other ways of electrical braking of induction motors.

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## From the net

Single-phase AC motors also allow for adjustable rotor rotation.

### Collector machines

These motors are found on electric drills, jigsaws and other tools. To increase or decrease the speed, it is enough to change the supply voltage, as in the previous cases. There are solutions for this purpose as well. The design is connected directly to the mains. The regulating element is a triac, which is controlled by a dynistor. Triac is placed on the heat sink, the maximum load power is 600 W.

If there is a suitable LATP, you can do all this with it.

### Two-phase motor

The apparatus, which has two windings. starting and working, in its principle is two-phase. In contrast to the three-phase has the ability to change the speed of the rotor. Its characteristic of rotating magnetic field is not circular, but elliptical, due to its design. There are two possibilities for controlling the speed of rotation:

These units are common in homes and businesses.

### Conventional induction motors

Three-phase electrical machines, while easy to operate, have a number of characteristics that must be considered. If you simply change the supply voltage, the torque will vary within a small range, but no more. In order to regulate the speed within a wide range, you need quite sophisticated equipment, which is difficult and expensive to assemble and set up just like that.

For this purpose, the industry has set up production of frequency converters that help to change the motor speed in the desired range.

The induction motor gains speed in accordance with the parameters set on the frequency converter, which can be changed in a wide range. The converter is the best solution for these motors.

## Calculation of sheave diameter

First determine the gear ratio, based on the input rotation speed of the drive shaft n1 and the required rotation speed of the driven shaft n2/ It will be equal:

If a motor with a drive wheel is already available, the sheave diameter can be calculated according to the formula for the transmission ratio i:

If the mechanism is designed from scratch, then theoretically any pair of drive wheels that satisfy the condition will do:

In practice, the drive wheel is calculated from the following dimensions

• Dimensions and design of the drive shaft. The part must be securely fastened to the shaft, matching its inner bore size, fit, and fastening method. The smallest possible pulley diameter is usually based on the relationship Drace ≥ 2.5 Din
• The permissible dimensions of the gear. When designing mechanisms, it is necessary to keep within the overall dimensions. The following axle spacing is also important. The smaller it is, the more the belt bends when it runs around the rim and the more it wears out. too great a distance leads to the excitation of longitudinal oscillations. The distance is also specified on the basis of the belt length. If there are no plans to make a unique part, the length is selected from standard range.
• Power to be transmitted. The material of the part must be able to withstand the angular loads. This is relevant for high power and torque.

the final diameter calculation is finalized by the results of dimensional and power evaluations.

## calculate the speed of the idler pulley

dear specialists please help me calculate the speed at the idler pulley with the known data: electric motor. 0.55 kW-1500 rpm (380 volts). It has a pulley-55 mm in diameter (driving), the driven pulley pulley-220 mm in diameter. What will be the number of revolutions on the idler pulley. thanks to all who responded.

375 revolutions. solved by the composition of the proportions.

Thank you very much! Could you please explain the whole calculation for future reference? can be in person.

Not the circumference, but the diameter or radius. It’s easier to measure. For sprockets and gears, you have to divide the number of teeth.

And if the engine shaft itself makes 1500 rpm then the 55mm pulley makes a lot less rpm than the shaft itself! isn’t it.

If you need to be very precise. First, the engine shaft speed will be less by the slip ratio that is printed on the engine tag, let it be 0.95, then the shaft speed will be 15000.95=1425 rpm. So 142555/220=356 rpm. and that’s without the slippage of the belt.

I only eat with a spoon. I don’t buy plastic bags. This is MY contribution to the preservation of nature.

and if the engine shaft itself makes 1500 rpm then the 55 mm pulley makes a lot less rpm than the shaft itself! isn’t it?

I’m no physicist or mathematician, but it seems to me that a pulley mounted on a shaft will make the same number of revolutions as the shaft, unless of course the pulley is fixed with a key.

Please help the motor 950 revolutions gearbox 1 to 10 in the gearbox is the pulley 200 mm what you need a pulley on the motor to be 40 revolutions on the shaft Thanks

I only eat with a spoon. I do not buy plastic bags. This is MY contribution to the preservation of nature.

Good day help with the calculation of the following parameters, the drive pulley 120mm slave 45mm. revolutions from 1000 to 3000 per minute, coupling shaft 6mm. at the other end of the shaft need to have from 30000 rpm at initial 1000 rpm to 90000, how can you do it.

Good day help with the calculation of the following parameters, the leading pulley 120mm idler 45mm. RPM 1,000 to 3,000 per minute, 6mm coupling shaft. The other end of the shaft needs to have from 30000 rpm at an initial 1000 rpm to 90000, how can you do this.

connecting shaft 6mm. what connects with that diameter? a lot of incomprehensible. revolutions from 1000 to 3000 on the drive pulley?

Good day.Please help calculate the speed on the idler pulley.driving diameter 130.idler 297. 3 kw. 1440 rpm.

Hello, please tell me what pulley I need if there is an electric motor 1420 rpm it has a pulley 50mm but you need to get about 65-75 rpm and the formula for calculating if not difficult, I’m tired of hand-turning the separator (. thanks in advance

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hello please tell me what pulley I need if there is an electric motor 1420 rpm it has a pulley 50mm but you need to get around 65-75 rpm and the formula for calculating if not difficult, I got tired of hand cage to twist(. thanks in advance

19 engine revolutions = 1 turn of pulley on the other end whether it is a gearbox or just an axle with a pulley.so that is in your case, the pulley on the motor measure the circumference we get ACCEPT 13cm.0.13 times 19 =2.47m circumference of the pulley to be searched for.1420 divided by 19 = 74.7368421 revolutions on the pulley we’re looking for.

Yanmar YM2020D 3T82B 1,350L 4wd front loader

So you need a pulley with a diameter of 950mm? I got it right?

hello please advise what pulley I need if there is an electric motor 1420 rpm it has a pulley 50mm but need to get around 65-75 rpm and the formula for calculating if not difficult, I got tired of hand cage to spin(. thanks in advance

Based on your conditions you need a pulley 1420/6550=1092mm for 65 turns, or 1420/7550=946 for 75 turns.

Hello, please tell me what pulley I need if there is an electric motor 1420 rpm it has a pulley 50mm but need to get around 65-75 rpm and the formula for calculating if not difficult, I got tired of hand cage to twist(. Thanks a lot

19 engine revolutions = one turn of pulley at the other end, whether it’s a gearbox or just an axle with a pulley.so in your case the pulley on the motor measure the circumference we get ACCEPT 13cm.0.13 multiplied by 19 =2.47meters the circumference of the pulley.Let’s check 1420 divided by 19=74.7368421 revolutions on the pulley we’re looking for.

hello please tell me what pulley I need if there is an electric motor 1420 rpm it has a pulley 50mm but need to get around 65-75 rpm and the formula for calculating if not difficult, I got tired of the cage by hand to twist(. thank you so far

19 turns of motor = 1 turn of pulley on the other end whether it’s a gearbox or just an axle with a pulley.So in your case, the pulley on the motor measure the circumference we obtain ACCEPT 13cm.0.13 times 19 =2.47 meter circumference of the pulley you are looking for.1420 divided by 19=74.7368421 of the rotation on the pulley in question.

The main thing is to figure it out and the rest is just trivialities

Yanmar YM2020D 3T82B 1,350L 4wd with front loader

## One channel motor controller

The unit controls a single motor, powered from 2 to 12 volts.

### The design of the device

The basic elements of the construction of the regulator are shown in the photo. 3. The unit consists of five components: two variable resistor with a resistance of 10kOhm and 1kOhm. a transistor model KT815A. a pair of two-piece screw terminal blocks for the motor output and an input for the battery

Note 1. Installation of screw terminals is not necessary. You can connect the motor and power supply directly with a thin stranded mounting wire.

### Principle of operation

Operation of the motor regulator is described in the wiring diagram With regard to polarity a direct voltage is applied to the connector XT1. Light bulb or motor is connected to the connector XT2. Variable resistor R1 is turned on at the input, turning its knob changes the potential on the middle output as opposed to the minus of the battery. Through the current-limiter R2 the middle output is connected to the base lead of transistor VT1. In this case the transistor is included by the scheme of regular current. The positive potential at the base output will increase as the middle pin is moved up from the variable resistor knob. There is an increase in current, which is due to a decrease in collector-emitter junction resistance in transistor VT1. The potential will decrease if the situation is reversed.

### Materials and parts

You need a circuit board measuring 20×30 mm, made of foil-coated on one side of a sheet of fiberglass (acceptable thickness of 1-1.5 mm). Table 1 shows the list of radio components.

Note 2. Required for the device variable resistor can be any production, it is important to comply with the values of current resistance shown in Table 1.

)Note 3. For currents above 1.5A KT815G transistor should be replaced by a more powerful KT972A (with a maximum current of 4A). In this case it is not necessary to change the PCB drawing, because the pin assignment of both transistors is identical.

### assembling process

For further work it is necessary to download the archive file located at the end of the article, unzip it and print it out. The regulator drawing (file termo1) is printed on glossy paper and the assembly drawing (file montag1) is printed on a white sheet of office paper (format A4).

Then the drawing of the circuit board (see photo). 4) glued to the current carrying tracks on the opposite side of the circuit board ( in photo. 4). It is necessary to make the holes (see photo). 14) on the installation drawing in the landing places. The assembly drawing is affixed to the printed circuit board with dry glue, and the holes must match. On photo.5 shows the pinout of the transistor KT815.

The input and output of the terminal connectors are marked white. Connect the voltage source to the terminal block via the clip. Fully assembled single-channel controller shown in the photo. Power supply (9 volt battery) is connected in the final stage of assembly. Now you can regulate the speed of the shaft with the motor, for this you need to rotate the variable resistor adjustment knob smoothly.

To test the device it is necessary to print out the drawing from the archive. Then you glue the schematic drawing to a piece of thick and thin cardboard ( ). Then the disk is cut out with scissors

## making the table

When it is necessary to assemble the accessories for the circular saw with their own hands, the first thing to do is to create the frame. It consists of the base and the tabletop.

The design of the second element is affected by the structure of the attachment of the working disc.

The process of making the key fixture for the circular saw takes place in several stages. They are described below:

• From the plywood sheet is created a blank of the functional table (tabletop). Work is performed according to the chosen parameters. On the sheet with a pencil on a ruler put the marks. The sheet is sawn with a jigsaw. The edges are processed by a routing cutter. The created workpiece is grinded.
• Marks for the saw are marked on the bottom plane of the table top. The workpiece that has been made is turned over. On the intended area the saw without the disk is put. The parameters of the sole are marked.
• Using a router in the material is created an opening of 8-10 mm marking the landing area.
• Trying on the saw. If necessary, the parameters are adjusted. Then areas of its fasteners and a slot for its disk are marked. If the material will be sawn at different angles, this must be taken into account when marking the kerf. It will receive a cross-section in the form of a trapezoid. The top will point downwards.
• The pencil is used to mark the stiffeners. You will later attach the legs to them.
• Work on the ribs. To create them we use 5 x 10 cm planks. They are placed along the perimeter at a distance of 7-10 cm from the edge of the table. The board is attached to the table top. Circle it on both sides. Using the ruler, its basic line for the trimmer is marked out. Here the positions of the self-tapping screws are marked. They are as follows: 5 cm. from the extreme side of each of the existing ribs. A distance of 15-20 cm along the entire length of the rib is observed. Drill through holes according to the markings you made.
• The longitudinal ribs are arranged. To do this, the boards are marked and sawn. They are glued to the tabletop. Clamps are clamped.
• Marking of the lateral stiffeners. The boards are sawn and glued as in Nr. 7.
• Clamps are held in place. The construction is pulled through using self-tapping screws on the created holes, which are pre-drilled on the outside. This ensures that the screw heads sink completely into the table top.
• Screw the ribs together with two self-tapping screws by 5 cm. Tightening is performed on all sides. Clamps are removed. This creates the table top.

## sharpening issue

The circular saw needs to be sharpened when these symptoms appear:

Ideally, it should be sharpened on a professional sharpening machine. If it is not available, you need a tool for sharpening circular saws.

• Disc is fixed firmly. It is taken out of the saw and clamped in a vice. Wooden strips are used for sharpening. It can be left in the saw, but a block can be inserted between the teeth. The block is against some surface.
• The starting tooth is marked.
• The file is sharpened at the backside of the tooth. You need to sharpen it several times. The force is small. Each tooth is sharpened in turn. The movement is uniform, the number of passes with the file is the same.
• The front parts of the teeth are handled. The principle is the same.

The tooth tips should be perpendicular to the disc surface.

All teeth are then inspected for flaws. Edges must not shine. If so, they are gently sharpened with a file.

Then the blade is checked in the case. It is placed in the saw. It works. A test block is used. If the saw is light, smooth and quiet, the sharpening is good.

Otherwise it is necessary to check the height of teeth. To align them, it is necessary to bring a marker to the working edge. Then the disc should go all the way around the other side of the rotation. A mark is left on all teeth. You can use it to adjust their height. The highest teeth are gently sharpened with a file.

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