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Installing a new heavy-duty electric grinder

Wireless testing makes it easier

July 2014

A technician at Continental Biomass Industries (CBI), in Newton, New Hampshire, recently traveled to a recycling plant where CBI was installing a new heavy-duty electric grinder. The grinder was to process the material left over after the hard materials like concrete, metal, and other recyclable material had been picked out.

Measuring current during start-up

One of the best features of a wireless system is being able to attach modules inside a live cabinet (wearing personal protective equipment, of course) then close up the cabinet and take measurements from a safe distance.

At a comfortable distance from the cabinet, the technician monitors grinder performance, looking for glitches over time.

"Grinders by nature consume a lot of kilowatts per minute, so we measure the current during start-up to make sure it isn't drawing any more than it needs, to help keep power costs down," the CBI technician said. He also needed to measure voltage to detect voltage drops.

He had recently acquired the Fluke CNX i3000 iFlex AC Wireless Current Module, CNX v3000 AC Wireless Voltage Module, and CNX t3000 K-Type Wireless Temperature Module. (Note: These tools have been replaced by Fluke Connect.) He decided that the grinder start-up project would be a great place to test the wireless tools for measuring, monitoring, and logging AC current, AC voltage, and temperature.

He connected the wireless current and voltage modules at the electrical panel to one of the three-phase 480 V power supply conductors feeding the motor. He also placed the temperature module probe on the grinder's motor case and later in the installation's electrical enclosure with the door closed, to measure inside temperature while the machine was running.

One of the best features of a wireless system is being able to attach modules inside a live cabinet (wearing personal protective equipment, of course) then close up the cabinet and take measurements from a safe distance.

Viewing readings

He viewed the current, voltage, and temperature readings simultaneously on his laptop using the PC Adapter and software. Because the system is wireless, he was able to position his laptop at a safe distance from the panel, which eliminated the need to wear special personal protective equipment (PPE).

Using the software, the technician was able to view and save several minutes of logged data to his laptop and see the results graphically. That was a good thing, because during the testing a problem occurred, causing the grinder to trip off-line.

"I pulled up the graph of the readings and was able to show the technicians how the machine ran for the last 15 minutes before it tripped," he said. "They could see when the problem started and the current curve just before the grinder tripped on overload. We were able to pinpoint the nature of the problem very fast based on the data log from the Fluke wireless current module."

Material too light for control settings

It turned out that the material being run through the machine was too light and fluffy for the control settings. The rotor was spinning so fast it created a draft that kept all of the debris on top of the grinder in the chamber, where it backed up and caused the machine to trip off-line. The technician solved the problem by changing the program sequence to accommodate the lightweight material.

Down the road

He expects to use the wireless system down the road to:

  • Solve problems quicker. The ability to log data and see current, voltage, and temperature measurements simultaneously in graph form helped the technician go back in time and see what was going on at the point a problem occurred. "The fact that I can log, save, and interpret all the data in one graph makes my job a lot easier," he said.
  • Maneuver in tight spaces. All wireless components are compact enough to fit into cramped spaces and the iFlex® flexible current probe easily fits around conductors in tight panels, making for quick and easy setup.
  • Save time. "The system definitely saves time because I can take measurements at a safe distance and not have to keep putting on and taking off PPE," he noted. "Because the modules are wireless, I can focus on other things while the devices are well-placed and taking measurements with minimal intervention from me," said the technician.

Additional Resources

Creating electrical and electronic components to turn wood waste into new usable items »
Find out more about Fluke Connect »