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Motors/Drives

New Fluke 438-II Power Quality and Motor Analyser measures both electrical and mechanical performance of electric motors

12jul 5Analyses electrical and mechanical performance on operational motors without mechanical sensors to extend system lifespan

Measuring mechanical loads typically requires load sensors that can be costly or physically inaccessible. The new Fluke® 438-II Power Quality and Motor Analyser uses innovative algorithms to analyse not only three-phase power quality but also torque, efficiency and speed, to determine system performance and detect overloaded conditions, eliminating the need for motor load sensors.

Read more: New Fluke 438-II Power Quality and Motor Analyser measures both electrical and mechanical...

Whitelegg at Drives & Controls Show 2016: Stand D680

feb 26 1The 2016 show will feature a major presentation of advanced Electric Motor Testing and Condition Monitoring Instruments from Whitelegg Machines.

Together with partners, Schleich Gmbh, Whitelegg Machines of Crawley will be presenting a comprehensive array of advanced motor testing and condition monitoring equipment.

Read more: Whitelegg at Drives & Controls Show 2016: Stand D680

Which of Your Process Motors are Likely to Fail?

wl 4 sept 15 1Some of your process motors could be close to failure with others running inefficiently.
 A motor running hot could be due to the mains power supply, the motor itself, or its load.   Sometimes the problem is not apparent and it is often difficult to find the cause, as many motors are tucked away in hard-to-access areas.

Read more: Which of Your Process Motors are Likely to Fail?

Complete package – the new “Sauer Marine Standard“ for starting air compressors

sauer-april-4Starting air compressors are only a small part of a new ship, but one that is all the more important during operation. For this reason, it is necessary that their most recent specifications are already available to shipyards when ordering. Otherwise, operators may face some disadvantages: inadequate operation, high maintenance costs, low machine availability and many more.

Read more: Complete package – the new “Sauer Marine Standard“ for starting air compressors

Advanced Rotorbar Analysis – False Negatives: Dual Cage Rotors

 advance rotobar-20022Ernesto J. Wiedenbrug, Ph.D., SM IEEE
Introduction
Some squirrel-cage motors designed for high start-up torque may get weaker over time, needing longer startup times and may perhaps even trip during line-start – but never show big problems in vibration or MCSA. This paper  explains what gives high startup torque motors their  special capabilities, describes a common failure mode  making it nearly impossible to find the issue using MCSA or  vibration, and diagnostic alternatives for these problems.

To continue reading the full case study, with images, please download the free PDF file here. http://csaanalysis.com/PDFS/Advanced%20Rotorbar%20Analysis%20-%20False%20Negatives%20-%20Dual%20Cage%20Rotors.pdf
To contact Whitelegg direct please visit http://www.whitelegg.com  

Advanced Rotorbar Analysis – False Negatives: Dual Cage Rotors

whitelegg pic 2Ernesto J. Wiedenbrug, Ph.D., SM IEEE
Introduction
Some squirrel-cage motors designed for high start-up torque may get weaker over time, needing longer startup times and may perhaps even trip during line-start – but never show big problems in vibration or MCSA. This paper  explains what gives high startup torque motors their  special capabilities, describes a common failure mode  making it nearly impossible to find the issue using MCSA or  vibration, and diagnostic alternatives for these problems.

To continue reading the full case study, with images, please download the free PDF file here. http://csaanalysis.com/PDFS/Advanced%20Rotorbar%20Analysis%20-%20False%20Negatives%20-%20Dual%20Cage%20Rotors.pdf
To contact Whitelegg direct please visit http://www.whitelegg.com  

Advanced Rotorbar Analysis – False Positives: Spiders / Axial Cooling Vents

whitelegg pic 3Ernesto Wiedenbrug, Ph.D., SM IEEE,
Virtually all rotors of motors above 100kW are designed with axial  cooling vents, potentially causing false positives for both prevalent  diagnostic technologies, vibration and MCSA. Fig 1 shows the rotor  with 8 spider-legs of a 2.4MW 6.6kV motor that was pulled out of  service due to such a vibration and MCSA false positive.
 This paper explains how to recognize problematic motors, the reason for these false positives, how these motors react, and how  to deal with them.
To continue reading the full case study, with images, please download the free PDF file here.  http://csaanalysis.com/PDFS/Advanced%20Rotorbar%20Analysis%20-%20False%20Positives%20-%20Spiders%20-%20Axial%20Cooling%20Vents.pdf
To contact Whitelegg direct please visit http://www.whitelegg.com  

FAQ – Issues of High Distortion Surrounding VFDs

whitelegg pic 4by Ernesto Wiedenbrug, Ph.D.
Variable Frequency Drives (VFDs) can introduce power quality problems to line-operated motors on the same buss, and also to the motors being driven by VFDs. This FAQ shows typical voltage and current waveforms for such systems, and touches upon some of the potential power quality problems.
To continue reading the full case study, with images, please download the free PDF file here.  
http://csaanalysis.com/PDFS/FAQ%20-%20Issues%20of%20High%20Distortion%20surrounding%20VFDs.pdf
To contact Whitelegg direct please visit http://www.whitelegg.com  

FAQ: Output voltage of a VFD has ‘flat’ spots – is it a problem?

whitelegg pic 5Ernesto Wiedenbrug, Ph.D.
Description:
The voltage waveform to the left in Fig 1 looks normal, but at another point in time it looks like the waveform to the  right of Fig. 1; where the waveform stays constant on the top and the bottom. What is going on? Is this a problem?
Fact:
VFDs don’t only change the frequency of the voltage, but also the voltage level in proportion with the frequency.
Comparing the frequencies:
Both plots show two complete cycles for the voltage waveforms; the one to the left takes 46.1ms for two cycles – which  means 43.4Hz, and the one to the right takes only 41.7ms, which means that the VFD is running at 48Hz. According to the Volts per Hertz control technique [1], this means that the VFD output voltage needs to be almost 10% higher for the waveform to the right.
To continue reading the full case study, with images, please download the free PDF file here.  
http://csaanalysis.com/PDFS/FAQ%20-%20what%20does%20it%20mean%20if%20the%20voltage%20waveform%20generated%20by%20a%20VFD%20has%20'flat%20spots'.pdf
To contact Whitelegg direct please visit http://www.whitelegg.com  

Startup Transients – Two Case Studies of Reduced-Voltage Starters

whiteleggpic6by Dave Olinger and Ernesto Wiedenbrug, Ph.D.
This paper discusses how voltage and current captures of motors starting at line frequency can be used to diagnose high resistance contact problems, and even  detect whether these problems are up-stream or down-stream from where the  measurements were taken [1-2]. These concepts are applied on startup transient   captures of two 8-pole 100hp motors which are started via 80% reduced-voltage  autotransformers (Fig. 1) [3]. One motor shows a high resistance contact below the  point of measurement, and the other transient capture was used to diagnose a  problem in the autotransformer, which has been verified to be shorts in the  transformer.
To continue reading the full case study, with images, please download the free PDF file here.  
http://csaanalysis.com/PDFS/Startup%20Transients%20for%20Reduced%20Voltage%20Starts.pdf
To contact Whitelegg direct please visit http://www.whitelegg.com