A Reliable Power Supply is the Heart of a System
A reliable power supply for any application needs to be planned carefully to help keep costs to a minimum whilst ensuring the highest level of safety. A reliable and failure-free power supply does not just depend on a good power supply unit. When you are looking to make savings, always bear in mind that the power supply is the 'heart' of every application!
In addition to the power supply unit, other components need to be taken into consideration for a reliable power supply. Depending on your requirements, this could include a DC-UPS (Uninterrupted Power Supply), battery modules, buffer modules, redundancy modules or, electronic circuit protection. Even environmental aspects and efficiency play a huge role. The efficiency and integration of the power supply into an energy management system are important factors too. How intelligent should a power supply be?
A Reliable Power Supply or Just a Cheap Design?
Almost all control panels, switchboxes and decentralised units have a 24 VDC power supply. If this power supply fails, for whatever reason, this will lead to unplanned downtime, additional costs and delivery problems. That is why failures need to be minimised or avoided completely. In some industries, such as glass production, potential production stoppages are even more critical because the process can’t just stop!
Each component must be reviewed and selected for your specific application. This may be a standard unit, a redundant design or even a fail-safe solution that works when the mains power supply fails. Do you also need to consider electronic circuit protection to selectively secure each unit?
Lutze Compact Series
Almost every modern power supply has a potential relay contact to report the operating status, e.g. to an overriding control unit. Intelligent power supply units, such as the Lutze Compact series, can also record and signal the DC power currently flowing, indicate when a current limit has been overstepped or signal an error on the AC input side.
Buffer Modules
Mains fluctuations or brief outages in the public grid can lead to downtime if the problem is not directly detected. A suitable solution is a buffer module that guarantees a smooth supply (eg. 20A for 300 ms at 24 V. DC) or an UPS for longer power outages and/or faults (the bridging time depends on the selected battery capacity). A UPS is by far the safest and most reliable solution, but also the most expensive.
Redundant Designs
A redundant design is a popular way of improving reliability. If a power supply unit fails, the entire supply is tapped from another power supply unit and the faulty device can be replaced. Many power supply units have integrated decoupling diodes that can impact on the level of efficiency. Special redundant modules supply information about the status of the power supply units, redundancy errors and show the symmetry of the power supply units.
Lutze LOCC-Box
Each application has various consumers, such as sensors, PLCs, actuators, HMIs or other devices which need to be protected with a fuse, either individually or as a group, ie. branch circuit protection. This will shut down individual faulty components within an appropriate time. If that doesn't happen, the power supply unit may become overloaded and shut down, leading to a complete power outage.
Modern intelligent current monitoring devices, such as the Lutze LOCC-Box, are ideal for this. The LOCC-Box has 10 current ranges up to 10A, providing the necessary protection and safe shutdown. Communication between the LOCC-Box and PLC is easy using inputs and outputs or your chosen field bus.
As you can see, there is a lot more to a power supply than meets the eye. When you are planning a new control panel or machine, there are a number of options that need to be taken into account. Attention to detail is the key to ensuring a reliable power supply, for the heart of your control system.
Looking for more information? We can help with that...
If you want to discuss the power supply requirements of your latest project, or simply want more information on Lutze Power Supplies, give us a call on 01254 685900. Our Technical Support Engineers will be happy to discuss the best option for your requirements.
|
