Author: John Mulindi
-
The Role Played By Edge Computing in Manufacturing
Edge computing can be defined as a distributed computing framework that brings enterprise applications closer to data sources like local edge servers. In manufacturing, edge computing offers an effective processing and storage choice since intensive data handling and storage can be kept on the plant floor. Edge computing has developed, and plays an important role…
-
How to Wire an Industrial Control Motor
Option 1: With a Toggle Switch Let’s consider a simple three-phase, 480V AC motor control circuit consisting of a contactor, overload block, control power transformer, power fuses or (you may use circuit breakers) and the associated components as illustrated in the figures below: The schematic diagram for the same circuit is shown below: The control…
-
Schottky Diode – Features & Applications
Schottky diode is fabricated as a metal-to-N junction rather than a P-N semiconductor junction. Also referred to as hot-carrier diodes, Schottky diodes are characterized by fast switching times (low reverse-recovery time), low forward voltage drop (normally 0.25 to 0.4 volts for a metal-silicon junction), and low junction capacitance. The forward voltage drop (VF), reverse-recovery time…
-
Basic Features of Cascade Control
A cascade control system typically consists of a primary or master controller that generates a control function that serves as the setpoint for a secondary or slave controller. That controller in turn utilizes the actuator to apply its control function directly to the secondary process. The secondary process then generates a secondary process variable that…
-
Combustion & Temperature Control for a Direct-Fired Process Heater
The figure below shows the control schemes applied to a direct-fired process heater. From the diagram above, the heat from the burning fuel is applied directly to the tubes carrying the process fluid in similar way as the water tubes in a steam generator. This type of heater is usually used as a reboiler in…
-
Fuses & Circuit Breakers vs. Overload Heaters for Industrial Motor Protection
A key component of any motor control circuit is some kind of device to detect a condition of excessive overload and interrupt the power to the motor before thermal damage occurs to it. An overload heater is a simple and common overload protective device that consists of resistive elements connected in series with the three…
-
How PLC Systems are Protected from Plant Voltages
Internally a PLC typically operates at 5 V dc. The external devices such as solenoids, limit switches, motor starters, etc. operate at voltages up to 110 V ac. The mixing of these voltages will cause irreparable damage to the PLC electronics. A less noticeable problem may occur from electrical noise introduced into the PLC from…
-
Key Facts about RS-485 Industrial Network
RS-485 network is used in many industrial applications to gather data and control addressable motor drives, PLCs, cameras, time clocks, barcode scanners for process control and other factory automatic apparatus. RS-485 devices can be connected to a computer and multi-dropped at various locations in a network style configuration. The devices can be up to 4000…
-
Industrial Motor Control Using Contactors
Motor contactors are large, high-current rated electromechanical relays. These are special relays in the sense that, they have heavy duty contacts that can handle the motor’s inrush current over many start and stop cycles. The contactor is actuated by an electromagnetic solenoid (coil) which pulls the contacts closed when energized. They also have an arc-suppressing…
-
Advantages of Fluid Power over Electric Power Systems
Generally fluid power systems tend to be insufficient, requiring much more energy input to the fluid than what is extracted at the points of use. When large amounts of energy need to be transmitted over long distances, electricity is a more practical medium for the task. Nonetheless, fluid power systems have certain advantages over electric…