on video How to make a soft starter - Triac BT136

 How to make a soft starter - Triac BT136

Occasional breakdowns of portable power tools - grinders, electric drills and jigsaws are often associated with their high starting current and large dynamic loads on parts of gearboxes that occur during a sharp start of the engine.

Device soft start the commutator motor described in is of complex design, it has several precision resistors and requires careful adjustment. Using the KR1182PM1 phase regulator chip, it was possible to make a much simpler device with a similar purpose, which does not require any tuning. It can be connected without any modification to any portable power tool powered by a 220 V, 50 Hz single-phase network. The motor is started and stopped by the switch of the power tool, and in its stop state, the motor is The device does not consume current and can remain connected to the network indefinitely.

The scheme of the proposed device is shown in the figure. The XP1 plug is included in the mains socket, and insert the power tool mains plug into the XS1 socket. You can install and connect several sockets in parallel for tools working alternately.

When the power tool motor circuit is closed by its own switch, voltage is supplied to the phase regulator DA1. Charging of capacitor C2 begins, the voltage across it gradually increases. As a result, the delay in turning on the internal thyristors of the regulator, and with them the VSI triac with each subsequent half cycle mains voltage decreases, which leads to a steady increase in the current flowing through the motor and, consequently, an increase in its speed . With the capacitance of the capacitor C2 indicated in the diagram, the acceleration of the electric motor to the maximum speed takes 2 ... 2.5 s, which practically does not create a delay in operation, but completely eliminates thermal and dynamic shocks in the tool mechanism.

After the motor stops, capacitor C2 is discharged through resistor R1. and after 2...3 sec. everything is ready to restart. Replacement fixed resistor R1 is variable, you can smoothly adjust the power delivered to the load. It decreases as the resistance decreases.

Resistor R2 limits the current of the triac's control electrode, and capacitors C1 and C3 are part of a typical phase regulator DA1 turn-on circuit.

All resistors and capacitors are soldered directly to the pins of the DA1 chip. With them it is placed in an aluminum casing from the starter Fluorescent lamp and filled with epoxy. Only two wires connected to the triac outputs came out. Before casting, a hole was drilled in the lower part of the body, into which an M3 screw was inserted with an outward thread. With this screw, the assembly is attached to the heat sink of the VS1 triac with an area of ​​100 cm2. This design has proven to be quite reliable when operating in conditions of high humidity and dust.

The device does not require any configuration. Any triac can be used, with a voltage class of at least 4 (i.e. with a maximum operating voltage of at least 400 V) and with a maximum current of 25 50 A. Due motor soft start, the starting current does not exceed the rated current. The reserve is only necessary if the tool jams.

The device has been tested with power tools up to 2.2 nkW. As the regulator DA1 ensures the flow of current in the control electrode circuit of the triac VS1 during the entire active part of the half-cycle, there is no restriction on the minimum load power. The author even connected an electric razor "Kharkov" to the manufactured device.

 How to make a soft starter - Triac BT136

Occasional breakdowns of portable power tools - grinders, electric drills and jigsaws are often associated with their high starting current and large dynamic loads on parts of gearboxes that occur during a sharp start of the engine.

Device soft start the commutator motor described in is of complex design, it has several precision resistors and requires careful adjustment. Using the KR1182PM1 phase regulator chip, it was possible to make a much simpler device with a similar purpose, which does not require any tuning. It can be connected without any modification to any portable power tool powered by a 220 V, 50 Hz single-phase network. The motor is started and stopped by the switch of the power tool, and in its stop state, the motor is The device does not consume current and can remain connected to the network indefinitely.

The scheme of the proposed device is shown in the figure. The XP1 plug is included in the mains socket, and insert the power tool mains plug into the XS1 socket. You can install and connect several sockets in parallel for tools working alternately.

When the power tool motor circuit is closed by its own switch, voltage is supplied to the phase regulator DA1. Charging of capacitor C2 begins, the voltage across it gradually increases. As a result, the delay in turning on the internal thyristors of the regulator, and with them the VSI triac with each subsequent half cycle mains voltage decreases, which leads to a steady increase in the current flowing through the motor and, consequently, an increase in its speed . With the capacitance of the capacitor C2 indicated in the diagram, the acceleration of the electric motor to the maximum speed takes 2 ... 2.5 s, which practically does not create a delay in operation, but completely eliminates thermal and dynamic shocks in the tool mechanism.

After the motor stops, capacitor C2 is discharged through resistor R1. and after 2...3 sec. everything is ready to restart. Replacement fixed resistor R1 is variable, you can smoothly adjust the power delivered to the load. It decreases as the resistance decreases.

Resistor R2 limits the current of the triac's control electrode, and capacitors C1 and C3 are part of a typical phase regulator DA1 turn-on circuit.

All resistors and capacitors are soldered directly to the pins of the DA1 chip. With them it is placed in an aluminum casing from the starter Fluorescent lamp and filled with epoxy. Only two wires connected to the triac outputs came out. Before casting, a hole was drilled in the lower part of the body, into which an M3 screw was inserted with an outward thread. With this screw, the assembly is attached to the heat sink of the VS1 triac with an area of ​​100 cm2. This design has proven to be quite reliable when operating in conditions of high humidity and dust.

The device does not require any configuration. Any triac can be used, with a voltage class of at least 4 (i.e. with a maximum operating voltage of at least 400 V) and with a maximum current of 25 50 A. Due motor soft start, the starting current does not exceed the rated current. The reserve is only necessary if the tool jams.

The device has been tested with power tools up to 2.2 nkW. As the regulator DA1 ensures the flow of current in the control electrode circuit of the triac VS1 during the entire active part of the half-cycle, there is no restriction on the minimum load power. The author even connected an electric razor "Kharkov" to the manufactured device.