• New Product Additions to our on-line catalog (now over 330 products!)
• Ask the Expert "What is the difference between the Heavy Spot and High Spot in Dynamic Balancing?"
• What's Hot?: See Below...
• Case History: Frame Vibration on Reciprocating Compressor
• RDI Newsletter Archive
• Dare to Compare: CMCP vs. CTC vs. Wilcoxon: BNC Switchboxes
• Case History: Frame Vibration on Reciprocating Compressor
• CMCP500 Monitor Update
• Trivia Contest: Win a CURADO 200 Reel and Allstar Rod!

CMVP40/50 SKF Vibration Pen Plus. As an SKF representative, I sold more Vibration Pens than anyone else in the USA. Now it's available on our web site. A Multi-parameter vibration monitoring tool (that fits in your pocket!), the Vibration Pen plus operates with the press of a button, measuring vibration according to ISO standards and utilizing acceleration enveloping technology to identify a range of bearing, gear mesh and other machinery problems.

S4A Portable Vibration Calibrator is designed to test and calibrate vibration transducers and monitoring systems. Because the Model S4A is portable, it is ideal for testing field mounted vibration transducers, cabling and related accessories. It's the most cost effective, portable shaker table on the market!

L80 PowerLine Laser Pulley Alignment System: Simply mount the laser source on the movable  sheave with the adjustable magnetic attachments. Install the three magnetic targets 120º  apart on the stationary sheave. The visual horizontal laser beam will hit the targets.  When all the targets agree the units is in alignment. This system clearly shows  parallel and angular belt misalignment - only $1,200.00.

Answer: A definable relationship exists between the heavy spot and the high spot which depends upon the rotor critical speed. If a rotor never experiences a critical speed throughout its operating range the heavy spot will always be the exerting force resulting in the high spot coinciding with the heavy spot, just as a weight being swung on a string exerts a displacing force on the rotation axis.

As the rotor surpasses the first critical speed the heavy spot and high spot split apart until the they are separated by about 180 . This phenomenon occurs because the rotor now rotates around its mass centerline instead of its geometric centerline, forcing the high spot to be the location of maximum displacement. If the rotor continues to increase its speed and experiences another critical speed the high spot rotates another 180 until the high spot coincides with the heavy spot. This 180 shift in the high spot's relationship to the heavy spot continues as subsequent critical speeds are surpassed.

For additional information about the relationship between critical speeds and the associated phase shift, see the RDI Application Note, System Response (F=MA)@ http://www.reliabilitydirect.com/appnotes/fma.html

For additional information on dynamic balancing check out http://www.reliabilitydirect.com/appnotes/balance.html

Nova-Strobe DB Plus is an all digital stroboscope employing the latest microprocessor technology to set the standard for speed measurements and stop motion diagnostic inspection for portable stroboscopes. It is the Hottest selling item in our entire catalog!

VISGAGE checks oil viscosity on-site; without thermometers or stop watches. The VISGAGE can be used to check any oil from a light spindle oil to heavy gear oils. Regular users of the VISGAGE include nearly every type of industry in the world, i.e., railroads, truck and bus lines, marine fleets, power plants, laboratories, oil distributors, etc.

CMCP811 Balance Weight Starter Kit comes complete with 25 each of 9 different sizes of squirrel cage clips ranging from 0.6 to 13.0 grams and 2 each of 13 sizes of c-clamps ranging in size from 0.1 to 8.0 ounces. The weights come indexed in a rugged, heavy duty, compartmentalized plastic box.

The AccuTrak® VPE-1000 is extremely sensitive to the ultrasonic sound of leaks and friction in industrial systems. So sensitive the VPE-1000 can hear the blink of an eye, yet most background noise will not interfere with detection accuracy. Use the VPE-1000 for a variety of leak detection and plant maintenance applications such as : Steam Traps, Bearing Wear, Valve Testing and Air, Vacuum, Refrigerant and Gas leaks. Perfect for schools, hospitals, hotels and other large institutional or industrial environments.