Soft Start and Inverter

With the Altivar inverter, induction motor can be adjusted in a wide range. Many applications not only require a wide range of rotation but also the stability of rotation of the desired reference value. To answer this need, it must be installed a control system.

Induction motor consists of two main parts, namely the stator and rotor. Stator is the part that does not move, consisting of layers of metal with grooves containing the coil-coil. Coil-coil is connected to 3 phase power source, to obtain a rotating magnetic field. The speed of rotating magnetic field depends on

number of stator poles and the frequency resources. This speed is called the synchronous speed, which is determined by the formula :

  Ns = 120 f
P

With Ns is the synchronous speed (rpm), f is frequency resources (Hz), and P is the number of stator poles.
 
The inverter is a device that can be used to convert the 3 phase power source into DC voltage which is then converted back to 3 phase power source with the appropriate frequency. This method can be used because it is known that induction motor synchronous speed is proportional to the frequency of its resources.

PLN has the resources of a constant frequency, which is 50 Hz. One effective way to produce a voltage with a frequency that can be regulated is by way of their own raises. For that we need a DC power source. This resource is derived from PLN's resources are rectified by the rectifier. Furthermore, these resources are filtered with filter DC to get DC power source that is more flat. Then through a series of switches (referred to as a bridge inverter) that can be controlled in such a way, those resources can be converted into 3 phase power source at the end of the load. By way of controlling the switching time of these switches using PWM signals (Pulse Width Modulation).

By using the inverter, it will be many technical advantages obtained when compared with other ways. Some benefits include: having a wider range of speeds, has some pattern to the relationship of voltage and frequency, has a facility designation meters, has a slope of acceleration and deceleration that can be set independently, compact, and more secure system.

Electrical interference and Causes

Light failure

● Electric Disturbance to be discussed are: electrical interference caused by currents and voltages, as is often the case in the operation of electric power.

● Electric Disturbance caused by the flow include :
- Over load current (load current), ie: more flows that occur within the electricity network due to, for example on the operation of the motor.
- Over current (over current / short circuit) : Flow with a value exceeding the rated value of equipment. Identifier value is: Ability Flow Conductivity (CRC) pelatan electricity.
- Leakage current (leakage current) : The current that flows into the earth or to other conductive parts. Leakage current can be caused by poor insulation.

● Electric Disturbance caused by stress include :
- Over Voltage (Voltage over): Surge Arrester.

The Difference Between Circuit Breaker, Switch and Fuse

● Circuit Breaker is :
Mechanical switch capable of connecting, flowing currents and decide on a normal circuit conditions and also able to connect, stream for a certain period and decide automatically flow to the abnormal circuit conditions, such as short-circuit conditions (PUIL Chapter-1.9).
● Switches / separator / isolator is :
Devices to separate or connect the circuit in a state of no or almost no load (PUIL Chapter-1.9).
● Fuse / safety fuse / fuse is :
Fusion devices with one or more devices that are specially designed and comparable to the open circuit where a safety fuse inserted and cut off the flow when the flow exceeds the value specified in the appropriate time (PUIL Chapter-1.9).

Dialogue Human - Machine

Which includes the category of tools that serve as media dialogue human with the tools / plant among others :

- Key Illumination
- Lamp Indications (Pilot Light)
- Push Button (Push Button)
- Selector (Selector Switch)
- Selector key (Key Selector)
- Cam Switches
- Switch Voltmeter (Voltmeter Cam Switch)
- Ammeter Switches (Cam Switch Ammeter)
- Switch Off-On
- Transfer Switches (Change Over Switch Cam)
- Switches multistep (multistep Cam Switch)
- Joystick
- Control Panel (Control Station)
- Beacon Tower Light and Illumination Segment
- Indicator Bank Diameter
- Trip Wire & Foot Switches
- Pendant

Detector and Sensor

- TYPE DETECTOR

In general, the detector is divided into 2 types :
- Detection by direct contact (touching the objects to be detected)
- Detection with no direct contact (no contact with the object to be detected)

Detector is included in the type DETECTION BY DIRECT CONTACT:
- Limit Switch
- Pressure Switch

Detector is included in the type DETECTION WITH NO CONTACT DIRECTLY:
- Photoelectric
- Proximity
- Ultrasonic

Limit Switch
Work based on the change in position of the actuator (Part in contact with the object being detected) that move the block contacts within the limit switches. Selection of type of actuator is adapted to the application, size, type and shape of the object to be detected.

Pressure Switch
Is a tool to maintain pressure at a certain limit (between PH boundary, with the lower limit PB). When the pressure reaches the value of PH (hence the switch will change state from On to Off) and if the pressure decreases and reaches the value of PB (the switch will change state from Off to On). The difference between the PH and PB is called Differential. There are 2 types of Pressure Switch :