Start of electric motors. Soft start device for electric motors

The soft starters of electric motors belong to the class of combined instruments. Their main task is considered to be the distribution of energy. They also help to control the power of electric motors. To ensure continuous operation of the motor, they are ideal.

If necessary, they will disconnect the power from the network fairly quickly. To date, soft starters are actively used in industry. In particular, models can be found in drilling and milling machines. For elevator stations such devices are suitable.

Standard starter circuit

The standard circuit of the soft starter is a set of contacts. By changing their position, the input voltage parameter changes. The cores of the models are often impulse type. The electrical coils in the devices are located behind the contacts.

In this case, thermal relays are used with low and high frequency. There should be two terminals for connecting the equipment. Direct movement of contacts is due to springs. Control units are diverse. The terminals for the models are usually located under the bottom cover. Gain filters are not installed on all starters.

Single-phase modifications

A single-phase device that provides start-up of electric motors (soft starter), is very simple in design. In this case, the coil is selected with a primary winding. Open-ended contacts for models are observed no more than four units. In this case, the core is located under the coil. Directly the thermal relay frequency must keep at least 55 Hz.

There are two terminals for connection to the motor in the devices. Springs for models are applied flat. Depending on the control units, the size of the starters varies. Some modifications are equipped with sensitivity controllers. The terminals are near the bottom panel. A soft starter is used for a single - phase electric motor, often for industrial machines.

Device of two-phase models

A two-phase device providing start-up of electric motors (soft starter) is only available with an impulse core. In this case, the thermal relays are set to low-frequency. Direct contacts for models can be up to four units. To change the phase, a trigger is used. Also, in many devices, gain filters are installed. Connect models through the pins on the rear panel. The terminals in such devices are located above the top plate. Control units are often provided with a sensitivity control. Meet biphase models in production can often. For milling equipment they fit well.

Modifications of three-phase type

The soft starters of the three-phase electric motor are operated by changing the position of the contacts. Coils in this case in many models are located behind the cores. A series of open contacts is installed on a special platform. The outputs of three-phase starters can be located above the control unit. However, most often they are located at the back panel.

Directly thermal relays in such devices are available at 60 Hz. The sensitivity can be adjusted in the equipment by means of a lever. The trigger is mounted above the core. To date, three-phase starters often work with marine engines.

Models for synchronous motors

A synchronous device providing start-up of electric motors (soft starter) is characterized by a reduced frequency. This is achieved through the use of closed cores. The coils of such models have an input voltage of 200 V. The thermal relays are mounted above the top platinum. The closing contact system is located on both sides of the core.

To increase the sensitivity of the device a special regulator is used. The terminals for models can be mounted at the top and rear of the panel. Gain filters are used rarely. Triggers are often installed.

Starters of asynchronous motors

To date, an asynchronous device that provides the start-up of electric motors (soft starter) is produced with a different bundle. The inductance coils of the models are set to 220 and 300 V .. In this case, the cores are often used open type. On average, the bandwidth parameter at them reaches 5 mp. However, impulse-type cores are also on the market. They differ from other models with increased sensitivity. At the same time, they wear out extremely slowly, and can work long. The open contacts in the devices are at the top of the plate.

Thermal relays are installed exclusively low-frequency type. The output voltage is at least required to withstand at 230 V .. Many models are connected via terminals. To change the position of the lower contacts, springs are used. They are often installed not of large diameter. Control units in all devices are equipped with blockers. Sensitivity regulators are also present in all configurations. By the type of triggers, the models are quite different. If we consider the soft starters of asynchronous electric motors with coils of 220 V, they are often of a wave type. However, phase analogs are also represented on the market.

A special attention in such devices deserves a trigger mechanism. As a rule, it consists of sets of conductors. In our time the most common are modifications to four contacts. If we consider models with inductance coils at 300 V, then in this case the triggers are always of the phase type.

Features of high-voltage engine startup models

High-voltage type starters are actively used in nuclear power engineering. The coils of such devices are often installed at 300 V .. The bandwidth parameter fluctuates around 5 mp. Direct contacts are available both mobile and non-mobile. The cores are installed in pulsed, as well as condenser type. They differ among themselves in terms of sensitivity. For today, impulse modifications are considered more reliable.

Thermal relays for devices are only like low-frequency ones. The working current parameter in the system reaches 5 A .. Flat plates are used to adjust the plates. The control units in the starters are available with the blockers, and without them. Triggers are often installed on three conductors. Gain filters in this case are used very rarely.

Separate attention in devices deserves the type of triggers. If we consider low-frequency devices, then they are chosen only of the wave type. With a decrease in the sensitivity of the device they cope well. The soft starter of the high-voltage electric motor is connected through the closure of the terminals. Often they are located on the top cover.

ABB Series

The soft starter of the ABB motor is characterized by the presence of phase triggers. Their advantage over wave modifications lies in the ability to quickly cope with electromagnetic interference. Thus, the engine operates more stably, and the revs maintains always at the desired level. Gain filters can be found only in devices of low-voltage type. Plates of models are fixed on flat springs. Triggers are installed on control units. The user can control the frequency directly by means of a lever.

The inductance coils in such devices of the ABB series are installed at 200 VDC. Contacts are located on either side of the plate. The cores are often installed in a closed type. As a result, their wear and tear is extremely small. Thermal relays can be found both stepped and reference type. There are only two terminals in the devices. The models of this type can be used only in networks with alternating current. In this case, the output voltage parameter should not exceed 220 V. In turn, the level of the limit toga can be a maximum of 6 A.

Device for starting "Schneider"

The device for smooth start-up of the electric motor Schneider is equipped with a 230 V coil. The load is maximum capable of withstanding 6 A. In this case, the network of open contacts is located near the thermal relay. The core of the model is of the impulse type. The bandwidth parameter is a maximum of 6 mp. A thermal relay is installed immediately below the plate. The outputs of the model are available with terminals. Movable contacts in the system are mounted on flat springs. The control unit is provided in the device standard.

The lock is in it. The trigger is set to four contacts. There is no gain filter in the starter. However, there is a lever for adjusting the frequency. The trigger is set to phase type. It is fixed in the device above the lower plate, next to the movable contacts. Suitable device for controlling synchronous motors.

Devices for sea vessels

Models for sea vessels include open-type cores. Directly the coils are set to 300 V .. Overloads the device for smooth start-up of the motor should be able to withstand at a level of 6 A .. The bandwidth parameter of such modifications reaches 7 mp. Special models are used to connect models. Often they are placed above the core near the plate.

Control units for protection can be equipped with blockers. The triggers for the device are quite different. If we consider low-frequency models, they are often installed on four conductors. In this case, the terminals should be near the core. Sensitivity for models of this type is not regulated. Gain filters are present only in starters with wave triggers. Movable plates in devices are installed near the thermal relays.

Modular models for nuclear power facilities

Devices for nuclear power are equipped with reliable protection systems. There are about five plates with contacts at the devices. The coils in the devices are installed very different. In some cases, they are attached to the rear panels. There are two outputs for connection to the devices. Thermal relays are often used in the low-frequency type. In this case, the cores are only suitable for pulsed ones.