3-VFDTom, a salesperson for a CMCO distributor and recent safety webinar attendee, asked the following question on variable frequency drives:

3-step infinitely variable control is 1st detent slow speed, 2nd detent HOLD, 3rd detent acceleration. If the application absolutely requires less than 2.0 second acceleration (Lodestar) can anything be done to accommodate?

Chris Zgoda, Corporate Trainer and webinar presenter, answers:

Thank you for your question. When the power is on and applied to the inverter, you can access the “U” parameters. The “U” parameters are the monitor parameters that allow the user to see what is happening. Too low of an acceleration time could present the following two issues:

  1. It could pull too much voltage off the DC Bus too quickly and cause a Uv (Under Voltage) fault.  Viewing the “U” parameter that monitors the DC Bus voltage you will see the DC Bus has approximately 340 Volts on it for a 230V hoist.  With an UP run button press you will note the voltage drops significantly at the first button press. With too quick of a ramp-up time, the voltage will drop even more causing an Under Voltage.
  2. Another potential fault is an Oc fault (Over Current) fault, meaning the inrush current that energizes the motor stator. Generally, the inrush current is about 150% of full load amps. The faster you take that motor from 0 RPM to 1725 RPM, the more current “energy” it will need.  So you could have a huge inrush current, especially if you have a heavy load on the hook, which may cause the drive to fault out, too.  You can also monitor the output current from the drive in the “U” parameter.

I might also note that the acceleration times are based on the full scale frequency of operation,  meaning an acceleration time of 5 seconds is from 0 to 60 Hz. If you press the pendant button for the 1st speed, it would not take 5 seconds to reach 6 Hz. It would be approx. 0.5 seconds.

Always follow factory service procedures when making adjustments to products.

For additional information, check out our Variable Frequency Drives Safety Webinar.

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February 19, 2015  Today, we are posting updates to this blog article originally posted in 2011. This article continues to be one of our most visited, and we feel it our duty to keep this very important safety information up to date.

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The Occupational Safety and Health Administration (OSHA) has the following regulations for slings:

  • 1910.184 (general industry)
  • 1915.122
  • 1915.113
  • 1915.118 (for shipyard employment)
  • 1926.251 (construction)

Effective June 8, 2011, all slings, chain, synthetic & wire rope, are required to have identification tags/labels permanently attached to them. This regulation applies to slings sold and used in the United States.

Historically, companies did not require wire rope slings to have permanently affixed identification tags/labels on them; it was not required per OSHA 1910.184. This has since changed. Tags/labels are now required.

Also, original load capacity tables found in the OSHA standards were based on information found in ASME B30.9 dating back to 1971.  New tables reflect the current industry standards for working load limits for slings, chain, and synthetic or wire rope.

Changes include:

  • All load charts for slings have been updated to current industry standards.
  • All slings, regardless if made of chain, wire rope or synthetic, must be marked with a tag/label. Now only properly tagged/labeled slings can be used.
  • Slings with detached tags/labels must be removed from service until new tags/labels can be permanently reattached.

To view the OSHA changes made in 2011 in its entirety or to download a copy go to: http://www.osha.gov/FedReg_osha_pdf/FED20110608.pdf

For information on Rigging training, please click here.

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Chain and Sling In-Depth Inspection Part #1: Twisting & Bending

February 13, 2015

This article is Part 1 of a 6-part blog series that will cover what professional riggers should consider when performing a chain & sling in-depth inspection. Today, we’ll discuss the effect of twisting and bending. Consider that chain is evaluated by applying loads in a pure tensile link end-to-link-end fashion and rated accordingly. Rigging chain around […]

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Does Welding Spatter Warrant the Replacement of a Chain?

February 5, 2015

Joe, a salesperson for a CMCO distributor and recent safety webinar attendee, asks: “Does welding spatter warrant the replacement of a chain?” Peter Cooke, CMCO Training Manager and Safety Webinar presenter, answers: Yes, weld spatter does warrant chain replacement. Weld spatter should be considered as heat damage. Because hoist chain is heat treated, any heat 410 degrees […]

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Santa Fe Springs Warehouse and Training Center Serve West Coast Market

January 29, 2015

Whether you’re located in the eastern United States or the northwest region of Canada, Columbus McKinnon is nearby. With warehouses located in Atlanta, Georgia; Tonawanda, New York; Edmonton, Alberta and Cobourg, Ontario, Canada; we are strategically located to meet the needs of customers across North America. Further improving our ability to serve our customers, we […]

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Columbus McKinnon now Better Equipped to Support Customers in Asia

January 20, 2015

Columbus McKinnon China officially opened its new facility in Hangzhou, China, on August 21, 2014. Many of our valued customers and distributors witnessed the event, alongside nearly 200 CMCO Asia Associates. Columbus McKinnon invested $6.4 million in the new facility. This investment will enable a 40% increase in capacity and give us the ability to […]

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Our Most Popular Blog Posts of 2014

January 13, 2015

As we look back at 2014 and begin planning for 2015, it’s interesting to see which of our blog topics were the most valuable and interesting to our readers last year.  With all of our blog posts, we look to provide you with valuable information to help keep you safe and make your job easier. […]

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Safety Takes Center Stage at Columbus McKinnon with Second Annual Safety Calendar Contest

January 5, 2015

Throughout Columbus McKinnon’s 140 year history, safety has always been an important part of the way we do business. Not only is the safety of our Associates important, but the safety of our customers is also a primary focus in the development of our products, services and training programs. In the spirit of our focus […]

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Do Chain Slings Need to Be Load Tested After a Repair Has Been Performed?

December 18, 2014

Xavier, a salesperson for a CMCO distributor, asks the following question: “I am doing some research on the guidelines and laws concerning repairs made to chain slings. I found some very conflicting information from OSHA and ASME. To summarize, ASME states that chain slings do not need to be load tested after a repair has been […]

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Free Safety Webinars to Resume in January 2015

December 11, 2014

Each month, the Columbus McKinnon training team hosts a free online safety webinar. We will not be holding a webinar in December, but to keep you focused on safety during this holiday break, we had a little fun making a video featuring five important tips to get you through the season safely. We hope to […]

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