Explosion-proof motor soft starter

1. Overview

QJR1 mine explosion-proof and intrinsically safe motor soft starter (hereinafter referred to as "soft starter") is another high-tech product designed and manufactured by our company. The advanced microprocessor, online control technology and power electronic control technology realize the soft start of the motor, which minimizes the mechanical and current impact. It has extended the service life of the equipment and is an ideal replacement product for hydraulic couplers and other motor starting equipments. It has the characteristics of advanced technology, safe work, reliability, convenient maintenance and long service life. Its application technology has reached the international advanced level. .

The soft starter is suitable for coal mines containing explosive gas (methane) and coal dust, at AC 50Hz In the 380V, 660V, and 1140V power supply systems, the three-phase squirrel-cage motors of 355A and below are controlled for soft start, constant current start, natural stop, and soft stop.

2. Main features

2.1 It adopts advanced power electronic device and digital control technology, and has fault alarm functions such as soft start, constant current start, natural stop, soft stop, start monitoring, overload protection motor phase failure protection, etc., which can meet the requirements of fan, pump and tape conveyor. Control requirements for different load objects such as machine and scraper conveyor.

2.2 By controlling the starting voltage of the motor, excessive peaks of starting torque and starting current are avoided. On the one hand, the working machine can be protected from excessive acceleration torque during the starting process of the AC motor, and on the other hand, the power supply system can be protected from excessive starting current, which greatly reduces the mechanical stress acting on the object to be transported. Reduces the wear and tear of the working machinery and transmission components, thus reducing maintenance, ensuring work safety and extending the service life of the equipment.

2.3 The soft starter's self-diagnosis and motor operation protection functions are complete. Including: power failure protection, line protection, under/over voltage protection, overload protection, phase sequence protection, phase failure protection, etc., and with remote control contacts. Therefore, regardless of the external or internal production of various types of interference and fault signals, the soft starter performance is safer and more reliable due to the above-mentioned protection functions.

2.4 Simple structure, easy installation and maintenance, it can be controlled locally or remotely via programmable logic controller (PLC) or other equipment.

2.5 The internal device of the soft starter body is the rail type, the handrail body has interchangeability; the control loop adopts the connector connection mode, which is convenient and quick to insert and pull, and convenient for maintenance and maintenance.

3. Technical indicators

☆ rated working voltage: AC380V, 660V, 1140V,

☆ rated working frequency: 50Hz;

☆ rated working current: 400A, 315A, 250A, 205A, 140A, 110A, 85A;

☆ soft start time: (0.1 ~ 99.9) s;

☆ soft stop time: (0.1 ~ 99.9) s;

☆ starting voltage: (40% ~ 90%) Ue;

☆ Weight: 400Kg

☆ Dimensions: 860 × 650 × 958 (mm).

4. Explosion-proof type and explosion-proof mark

Mine explosion-proof and intrinsically safe Exd[ib]I

5. Structural features

The upper part is the wiring cavity and the lower part is the main cavity.

There are 3 main circuit inlet power line columns, 3 main circuit outlet load terminals and 2 seven-core control line terminals in the wiring cavity. There are two main circuit cable introduction devices on both sides, the maximum outer diameter of the incoming cable is Φ79mm; there is one control line incoming device on each side, and the outer diameter of the incoming cable is Φ12.9mm.

The main chamber has a soft starter assembly, control transformer and bypass contactor, all of which are mounted on a drawer rack for on-site maintenance.

Loosen the two fixing screws on the movement, unplug the connector on the terminal block, remove the power supply and the power supply line, and the whole movement can be pulled out from the main cavity for maintenance.

6. working principle

The torque of the motor is proportional to the square of the voltage applied to the stator end, and the motor current is proportional to the terminal voltage at the stator end. Therefore, the acceleration torque and the starting current can be controlled by the control voltage, and the voltage is controlled by controlling the conduction angle of the thyristor.

The main circuit of the soft starter adopts three pairs of anti-parallel thyristors (see electrical schematic diagram), and uses the full digital control technology to complete the control of the voltage and current of the motor terminal, thereby realizing the soft start and operation protection of the motor.

During operation, after receiving the control signal, the soft starter controls the conduction angle of the three-phase thyristor according to the set parameters, so that the motor starts smoothly according to the set mode. After the start is completed, a signal is sent from the controller to close the bypass vacuum contactor. The thyristor is suspended to reduce operating losses. The microprocessor continues to monitor the motor operating parameters and protects all types of faults.

When parking is required, after the parking signal is given, the vacuum contactor is disconnected first, and then the starter performs soft stop according to the set parking mode.

7. Conditions of use

※ Altitude ≤ 2000m (above the height should reduce the capacity)

※ Ambient temperature -10 °C ~ +40 °C

※ Relative humidity ≤95% (+25°C)

※ No significant vibration and shock vibration

An environment without significant damage to the insulating gas or vapor.