Power Supplies

Getting to a Better–and-Cleaner Power Source For Machine Builders

These Greater Power Levels Arise From Making Measurements at Specific Times and Applying Proprietary Algorithms. These Allow Greater Accuracy of the Secondary, or Output, Side

By Hank Hogan

Power supplies are growing more efficient and capable. With help, they can better deal with electrical pollution. For machine builders, these improvements promise less expense, better performance and greater reliability.

For example, chipmaker Texas Instruments' latest innovation eliminates components, specifically the optocouplers used for isolation in the feedback regulating the power source output. Optocouplers cost money and can degrade with age, according to Ramanan Natarajan, team manager of TI's power supply systems applications and solutions.

TI's approach reads the voltage on the transformer auxiliary winding from the primary side of the power supply. Others have done this, but typically below a 30-W output. Industrial applications need more, something made possible with TI's technology.

"We're able to make this primary side regulation technology support higher and higher power levels in the DCM and CCM [dis- and continuous conduction] modes. We have today reached about 130-W peak," Natarajan says.

These greater power levels arise from making measurements at specific times and applying proprietary algorithms. These allow greater accuracy of the secondary, or output, side.

Also Read:  Why Fluid Power Matters as a Machine Motion Source

At Pepperl+Fuchs, noteworthy advances can be found in the company's diagnostic modules. According to Robert Schosker, power supply product manager team lead at P+F, these modules monitor input and output voltages, temperature, current draw and other data that could signify problems. A high current draw from the field indicates there are some other issues, not with the power supply necessarily, but possibly with the field devices.

Dean Norton, vice president of marketing at Wago, sees power supplies evolving into products with advanced features, such as the ability to supply substantially more current for short periods of time. Such a capability ensures reliable tripping of circuit breakers or starting loads with high inrush currents. Other improved capabilities involve monitoring. "Monitoring features include an LCD display of the current/voltage output for line monitoring or serial ports for connection to a PC/PLC for trend analysis, alarm conditions, data collection of input/output voltage, current, operating hours, etc.," Norton explains.

Omron Automation and Safety responded to another trend, according to Dan Nigro, product marketing manager for control components. Panels are getting smaller, so Omron's recently released, switching power supplies are about 5% thinner than previous products. The efficiency of these latest power supplies runs as high as 93%, up from the mid-70% range years ago.

Rockwell Automation's power supplies have been 95% efficient for some time, according to Coman Young, global product manager for power supplies and UPS. He says that power supplies are shrinking, with products now about half the size of eight years ago.

There also has been an increase in current levels. Where before there might have been a 20-A power supply, now there is a 40-A supply. This greater capacity allows a single source to, for example, supply the power to start a conveyor belt.

Greater power levels arise from making measurements at specific times and applying proprietary algorithms, providing greater accuracy of the output side.

A beefier source enables power supply consolidation, as do other products. Rockwell, for instance, has a line of electronic circuit protection devices. These reduce the need to have current-limiting sources for sensors and other devices.

"You can still feed those noisy loads or whatever you have that has those coils,” Young says. "I put this electronic circuit protection in series with my sensitive devices, where it will trip if it goes above a set current."

Power quality is a big push for Rockwell, Young adds. The company has products that mitigate voltage sags, spikes, interruptions and transients.

Power quality is a focus for Falcon Electric, a maker of industrial UPSs. The company's products also do line conditioning, smoothing out voltage, current and frequency swings. That can correct problems arising in a factory, according to Michael Stout, Falcon's vice president of engineering. He recalls an instance where a large soft drink maker was throwing out entire production runs from time to time. What was going into the power supply was the problem.

"Because of the large three-phase motors operating on the line, when they were starting or stopping, they were producing transients, and the PLC couldn't handle it," Stout says.