by Bob Bob

Protection for Computer Controlled Milling Machines

Computer Controlled Milling Machines

120/208 VAC 3-phase Protection for Computer Controlled Milling Machines for a Large Industrial/Manufacturing Company.

ZeroDT was contacted to recommend protection options for four large computer-controlled milling machines. Previous power surges had caused permanent damage to the units. This resulted in a ripple effect that caused serious efficiency and output problems within the (entire) factory. The repair, however, would first require purchasing new circuit boards from the milling machine manufacturer and having them installed by factory technicians additional downtime before ZeroDT could provide the solution to prevent recurrence of the problem.

We recommended installing surge protection right at the inputs (120/208 volt 3-phase AC power in a WYE configuration) to each of the milling machines, we also recommended that the surge protectors should utilize SASD (Silicon Avalanche Suppression Diode) technology so that they would not degrade with usage. Because the company is located in a frequent lightning area of Texas, additional power surges occur anytime the current is interrupted, as well as transients created by other machines in the factory. The surge protection recommended is the same protection technology that is used in the ZeroDT devices, but on a much larger scale for industrial applications of AC power. Most AC power surge protection devices utilize MOVs (Metal Oxide Varistors) as they are less expensive but come with the trade-off of degrading with every surge or transient that they handle and unless replaced periodically will lead to equipment damage. 

The Engineering Team at ZeroDT put together a design for a small (10” x 10” x 6”) wall mountable enclosure that contained non-degrading SASD-based surge protection for each of the 3 phases of AC power, along with the necessary fuses and terminal blocks to enable it to be easily installed at the AC power input to each of the milling machines. After a review of ZeroDT’s design drawings, the customer placed a P.O. for four of the units for ZeroDT to procure the parts and build up the units. We were able to go from the initial discussions with the customer on how to protect the milling machines to the delivery of four completed 120/208 VAC 3-phase protectors in just under four weeks.