Lawrence Berkeley National Laboratory (LBNL) under the direction of the U.S. Department of Energy's Advanced Manufacturing Office is nearing completion of its Motor System Market Assessment (MSMA). This webinar, presented by the staff of LBNL, will highlight the results on motor system maintenance practices. This webinar is free for EASA members.

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As VFDs and their applications have become more complex, it can be difficult to determine what type of VFD will be required for an application and how the motor needs to be controlled. Learn more about the basics of  low voltage AC drive types and control methods.

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The latest edition of EASA's flagship standard — ANSI/EASA AR100-2020: Recommended Practice for the Repair of Rotating Electrical Apparatus — is now available for download.

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Winding RTDs are resistance-based temperature monitoring devices. Aside from just reporting winding temperature, here are some tips for maximizing the benefit of RTDs. Place six RTDs, spacing them uniformly around the core so there are two per phase. Provide a location map, numbering the RTDs, starting with the number 1 RTD in the 12:00 position. Number the RTDs clockwise facing the connection end. Knowing where each RTD is located (which phase, as well as the physical location in the stator) provides some powerful diagnostic ability. Possible causes for deviation in temperature are:

• Two RTDs reading high, and both in the same phase: Check for voltage / current unbalance; higher current in one phase causes higher temperature in that phase.
• If the number of circuits is half the number of poles, circulating currents can occur. This situation can be exacerbated by uneven airgap which cause a further temperature increase. The corrective action, in this case, is to use the appropriate extra-long jumpers when connecting the winding.
• Higher temperature indicated in adjacent RTDs may indicate obstructed ventilation. Some possible causes are clogged filters, missing soundproofing, displaced weather-stripping, poorly positioned air baffles, or a missing J-box cover.
• Some manufacturers place all six RTDs across the 10:00 to 2:00 portion of the winding, to report more uniform temperatures. By distributing the RTDs symmetrically around the stator -- instead of just on the top -- the reported apparent temperatures often look alarming. Before returning the motor, let the end-user know where they were originally, and explain that the symmetrical placement will yield more realistic results. 

Technology has played a larger role in decision makers’ lives over the past year. Many buying influencers of all levels are spending more time in front of their computer, away from team meetings or water cooler conversations. Many of these professionals may be working from home, navigating technical challenges. Fortunately, many buyers use calendar requests, Zoom calls or other technical tools of the working world that escaped them before. We can utilize their recent adoption of technology to help set appointments. Sales professionals are setting appointments simply by sending their customer or prospect a calendar invite or Zoom call request. Since buyers are more familiar with communicating this way, they may be more comfortable clicking “accept” to your ask. I’ve heard one story where a sales professional created 10 calendar invites, typed in his interest-creating message with an attachment and sent it off to 10 customers. Within five minutes he secured five accepted appointments, all for very little time investment.

Submitted by Kevin Femal
Marketing + Industry Awareness Committee Member
EMS Industrial, Inc.
Madison, Wisconsin