DIN rail-mounted industrial power supplies provide DC power for industrial components for industrial control, assembly, testing, and monitoring tasks, as well as other automation equipment that uses DC power. These power sources are usually located in electrical cabinets and control panels, which are connected to complex power and communication networks involving countless components. Outside the control cabinet, the power supply can also be found on the machines that provide power for HMI, motor drives, actuators, sensors, etc.
The components connected to the industrial power supply are divided into two categories. The first category includes power distribution or intermediate power components, which do not use power by themselves... but are used to connect power to industrial components that require power while performing other key functions. The second category includes electronic and electromechanical components that consume a lot of power to operate. The industrial components in the latter category can be directly connected to the power source-or indirectly through the intermediary or power distribution components in the first category. After all, industrial components that consume a lot of power are smart systems that contain processors and microchips that require fine shapes and controlled power inputs.
Image of terminal power distribution from Shutterstock
In fact, there are various industry-specific power supplies and accessories-especially suitable for automotive, processing, aerospace, medical, food and beverage, and discrete manufacturing industries. It is impossible to list all the special equipment that uses power in these industries. In other words, the following is a short list of very common industrial components that are often combined with DIN rail-mounted industrial power supplies.
Power distribution and wiring terminals belong to the first category above-intermediate power components that do not use power by themselves. These modules are used to distribute power from a single power source to numerous industrial components.
Mounted on this DIN rail are terminal blocks and (in the blue housing) a relay based on electromechanical action.
The intermediate power components have different sizes and different numbers of output terminals. In addition, power distribution and wiring terminals usually have fuses connected to each terminal. The rating of the fuse may be different...for terminals with different ratings. These components are usually connected directly to the power supply from the output terminals of the power supply to their input terminals. They can also be connected via an uninterruptible power supply or UPS.
UPS is an industrial electrical component that can ensure continuous power supply to the connected load through the battery when the power supply cannot be input normally. They will usually be used for a short period of time until the main power supply is restored. The UPS may have a built-in battery, or it may be a stand-alone unit with a separate battery. In both configurations, the input terminals of the UPS are directly connected to the output terminals of the power supply. UPS systems with independent batteries have additional battery input terminals. This means that the battery is never directly connected to the load. In addition, the UPS may have multiple outputs connected to different loads. These industrial components can be used as either the first type of equipment or the second type of equipment (as described above), because after all, they are powering other equipment—and require electricity to perform their main functions.
The circuit breaker protects the connected hardware from surges and overcurrents. They are designed to trip (cut off the current) when the passing current exceeds a certain level-thereby protecting the connected industrial components. The way the circuit breaker is connected to its power source depends on:
• Type of circuit breaker-single or double pole • Type of power supply-whether it is single phase, two phase or three phase • Number of components connected to the circuit breaker • Number of circuit breakers used.
When multiple circuit breakers connect multiple components to a single power source, jumpers can connect the circuit breakers to form a group. Another common configuration is a two-pole circuit breaker that connects the power source to multiple components. Here the output terminal of the power supply is connected to the input terminal of the circuit breaker, and the output terminal of the circuit breaker is connected to any number of industrial components. One caveat is that all equipment connected to the same circuit breaker must have the same rating. Circuit breakers belong to the first category of devices mentioned above because they do not consume a lot of power to perform their main functions.
The PLC is connected to the power supply.
A programmable logic controller or PLC is a dedicated industrial computer that can perform monitoring, control, and automation in an industrial environment. They are usually installed in a control panel...and from there are connected to industrial components, through which various commands are executed. These command components include sensors and limit switches, actuators, alarms, Ethernet switches and many other industrial components. Therefore the PLC's inputs and outputs (whether integrated or through separate modules) are connected to its programmable CPU. The input accepted by the PLC includes feedback and status updates; the output signal is a low-power control signal. PLCs do not supply power to the equipment to which they are connected. On the contrary, PLC has positive and negative power input terminals, they can:
• Directly connected to the output terminal of the power source or • Indirectly connected to the power source through circuit breakers, power distribution components, UPS or other power components.
Most DIN rail-mounted industrial power supplies have spring clips or screw output terminals to simplify the physical wiring process between the power supply and other devices. The connection is made through cables of the specifications, number of strands, shielding and sheath types defined by the component supplier.
The spring clip terminal on the power supply only requires the electrician or installer to lift a small lever, insert the stripped connection wire into the corresponding wire socket, and then close the lever. Screw terminals provide more options, but require an electrician to use a screwdriver to secure the wires in place. To connect the connection to a power supply with this type of socket, the electrician loosens the socket screw until there is enough margin to allow the wire or wire terminal to be inserted-whether this is just a stripped wire end or a wire terminated with a ring or pin-profiled End joints. Then after inserting the wire, the electrician tightens the screw down until the wire is firmly fixed in place.
Some specifications and installation tips: Specify a power supply large enough to meet the rated power (in watts) of all components it will serve. In addition: When connecting industrial components to the DIN rail-mounted industrial power supply, please confirm that their ratings match-to prevent damage to the power supply and equipment... and ensure reliable operation. Connecting a 5-A circuit breaker to a 10-A power source will continuously trip the circuit breaker. If the installation involves a DC electrical system, please specify how the system should be grounded... by grounding the negative or positive terminal of the power supply. ⚙️ Etiido Uko's contribution• Mechanical engineer
Lisa Eitel has been working in the sports industry since 2001. Her areas of focus include motors, drives, motion control, power transmission, linear motion, and sensing and feedback technologies. She holds a bachelor's degree in mechanical engineering and is a member of the Tau Beta Pi Engineering Honor Society; a member of the Society of Women Engineers; and a judge of FIRST Robotics Buckeye Regionals. In addition to her contribution on motioncontroltips.com, she also leads the production of quarterly motion problems in the design world.
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