Smooth start-up of an asynchronous motor: device, circuit

Soft starters are available forasynchronous motors of different power. Many models are aimed specifically at providing overclocking. However, there are configurations that can provide a smooth stop of the engine. Starters are used most often on conveyors.

They are also installed on tapeconveyors. For pumps, they are ideal. The operating principle of the models is based on a gradual decrease in the current load parameter. In order to understand this issue in more detail, it is necessary to consider the device of a simple starter.

Standard starter circuit

Reversible start-up scheme for asynchronousThe electric motor includes a step-down transformer. The relay in this case is installed with a high-voltage winding and can cope with a very large overload. If we consider powerful models, then they have rectifiers.

Also the start-up circuit of an asynchronous electric motorinvolves the use of resistors of the stitched type. In some configurations, you can find transceivers. These devices are designed to reduce the clock frequency of an induction motor. Thus, it can last for many years. The kenotrons in models are often used with stabilizers.

Single-phase starters

Smooth start of the induction motor forThe single-phase starter counts due to the voltage applied to the transformer. Then it is fed to the relay, where the conversion takes place. Most modifications of this type are equipped with expanders. They are applied only code, or commutated. The outputs are used to connect an asynchronous motor.

Some modifications are sold with regulators. Direct rectifiers are installed operating. The parameter of the threshold overload of the models does not exceed 40 A. In turn, their power is at the level of 5-10 kW. The parameter of the supply voltage varies from 100 to 220 V. By the degree of protection, single-phase modifications are quite different among themselves. Some of them are vulnerable to moisture or dust, and this should be considered before purchasing.

The device of two-phase models

Two-phase starters should be considered atan example of general production models. This type of electric motors are asynchronous (three-phase) technical characteristics have the following: power 5-15 kW, maximum overload 40 A, input voltage 220 V. Anchors for modifications are used with the primary winding. Models use transformers of a reducing type. It is also important to note that the relays are installed with stabilizers. Modulators for these devices are only suitable for orthogonal. Modifications with resistors are very rare.

Modifications of three-phase type

Smooth start of an induction motor withThe help of three-phase starters occurs quickly. If we talk about the characteristics of the models, it is important to note that the threshold load of the device can withstand an average of 60 A. The power of many models exceeds 5 kW. The disadvantage of these devices is considered to be a low minimum temperature threshold. In the cold, it is strictly forbidden to use them. The modulators for the models are of the orthogonal type.

Expanders can often be found code. By the parameter of the current capacity, they are quite different. Transceivers, as a rule, are fitted with single-pole switches. Transistors for models are mainly broadband. On the degree of protection starters are different. Many of them are not afraid of high humidity, but in this case, much depends on the manufacturer.

Starter for models with squirrel-cage rotor

With squirrel cage motorasynchronous (three-phase) technical characteristics have the following: power from 10 kW, the maximum overload is 40 A, the input current is 220 V. The majority of starters are equipped with down-type transformers. Some configurations on the market are represented with stabilizers. It is also important to note that models with a power of over 12 kW are equipped with special dinistors.

To stabilize the output voltage, theyfit perfectly. Expanders in all devices use code. However, thyristors are suitable only for a semiconductor type. On average, the minimum temperature of the device is able to keep at a level of 5 degrees. Direct start of the induction motor with a squirrel-cage rotor is carried out through the output contacts on the upper part of the housing.

Features of models for starting a high-voltage motor

Soft start of the induction motorhigh-voltage type is carried out due to power transformers. In this, only electromagnetic regulators are used for control. Directly the kenotrons are set to frequency ones. Transistors for these models are suitable for high throughput. There are two isolators in the devices. The output contacts are used to connect high-voltage motors. Models with dinistors are rare.

Starters of ABB series

The starters of this series are considered verycommon. In this case, the start of the engine is due to a phase change. Directly the current is converted by means of dinistors. By type of relay, the models are quite different. The power of the models ranges from 4 to 12 kW. In turn, the supply voltage is an average of 220 V. The distributors are installed only in the code type.

If we talk about modulators, then on modelshigh power they are orthogonal. It is also important to note that the transceivers in all starters of this series are single-pole. Most often, models can be found on conveyors. Stabilizers in devices are absent. The protection system at them is established by series IP-62, and they are not afraid of the raised humidity.

Device for starting "Schneider"

The specified starter differs in increased inputvoltage at the level of 200 V. In this case, the starting of the engines is carried out through a power transformer. The relay in this model is used with the primary winding. According to the documentation for the device, the threshold overload parameter is at 40 A. The resistor in the presented configuration is installed in the configuration, and the expander is of the code type. Problems with the phase change in this device are rare. A qualitative modulator is used to convert the current. The regulator of speed of rotation of the asynchronous electric motor of electromagnetic type. The manufacturer provides an expansion dinistor for a model of this type. There is no zener in the device.

Starters for sea vessels

Models for sea vessels are produced in different wayspower. It starts the email. motor through a power transformer. If we consider two-phase modifications, then they are equipped with rectifiers. Modulators, in turn, are installed both orthogonal and noncondenser type. Resistors, as a rule, are used in tuning. Three-phase modifications of the starters are equipped with stabilizers. Thyristors are used to change the clock frequency. Kenotrons in this case are installed with high capacity.

Modular models for nuclear power facilities

Modular starters are distinguished by a high parameteroutput voltage. It starts the email. motor due to the transformers of the reducing type. For two-phase models, power analogs are used very rarely. Rectifiers in devices are installed only with relays. Expanders are of a commutated type.

Degree of protection in starters is provided for the seriesIP-67. Elevated humidity and dust models are not afraid. Isolators in devices are available from three to six units. Power ranges from 4 to 10 kW. The regulator of the speed of rotation of an asynchronous electric motor they have electromagnetic type. It is also important to note that the thyristor blocks are installed semiconductor with contacts.

Modular devices for lift stations

For elevator stations only two-phasestarters. Start-up of an induction motor with a starter in this case is due to the operation of the step-down transformer. Overload current models are required to keep the level of 40 A. Expanders for uninterruptible power supply are most often used in the code type.

Direct transceivers are usedsingle-pole. Modulators in this case are rarely used. However, modifications with regulators are encountered. Resistors for models are used as a tuning and pulse type. Modifications with kenotrons in the market are not met. With transistors, transistor blocks perfectly handle. It is also important to note that models use insulators.

Characteristics of 60A models

Starters at 60 A for lift stations are suitableideally. Soft start of the induction motor in this case is provided by power transformers. Relay for many models with primary winding.

For normal operation of the starter,only orthogonal modulators. Directly thyristor blocks can be met with a semiconductor type. Threshold load they are able to withstand a large. The average power of models varies from 10 kW.