Recent content by davidd31415

Does anyone know of a measurement device rated for dust concentrations from 2000 mg/m^3 to 4000 mg/m^3? The dust particles are 20 um to 30 um in diameter. The dust is being agitated one or two times an hour in an environmental test chamber. I am looking for the least expensive (low accuracy...

Does anyone know if ISO standards permit the use of RFID tags as opposed to labels for identifying calibration information on measurement devices?

Not sure what happened to the end of my original post there, I was meant to write "the length of the cables may make it impractical." Thanks Steve, I like the accelerometer box idea. Out of curiosity, have you found the cable to effect the calibrations? David

This may seem like an elementary question but does anyone have a recommendation on how to store and organize accelerometer cables? I have been winding each cable and placing it in a plastic Ziploc bag. Perhaps this simply is the best method? I’ve tried plastic ties in the past but even with...

Yes, the failed open failure mode is worrisome. I've planned to limit the maximum output voltage at the power supply outputs to protect against this case. The problem with larger conductors is that anything larger than 18 AWG become impractical due to space available for wire routing, wire...

Thanks Keith, Reasoning is to perform tests per specifications. Losses vary as ambient temperature surrounding devices under test change. Standard procedure has been to control the voltage at the power supply output terminals and offset it slightly to ensure the voltage at DUT terminals is...

itsmoked, 1. The H-bridge is composed of four relays. 2. I am running one of two motors at a time with one power supply and one H-bridge. I'd like to sense voltage in one of five ways depending on which of the five modes is active... 000 - M1 off, M2 off - sense at power supply output 100...

GeekEE, Thanks that's what I was looking for. IRstuff, Thanks for the table links. I'll remember they're in this thread.

Ok, How about resistance per length as a function of wire diameter? How can I calculate that?

I've been using this 'nomograph' to estimate voltage drop in conductors: http://www.kepcopower.com/nomomax.gif How would I calcualte voltage drops with equations? Is this something burried in Maxwell's equations? Thanks

Thank jimkinney, Interesting thread but I am interested in where to place the control accelerometer, not how to mount it. I found this: http://archive.evaluationengineering.com/archive/articles/1006/1006control_accelerometer.asp I'm interested in a similar discussion related to sinusoidal...

Is anyone familiar with the practice of mounting accelerometers on DUTs during vibration durability tests? I've been hearing conflicting (and rather passionate) views on if this is acceptable from a few different people. I'd like to find discussion of this subject haven't found one so far...

The benefit I see is similar to that provided by magnetic accelerometer mounts. Setup and teardown times would be reduced. If fixture can not be coupled to the shaker with a rigidity similar to what is achieved with fasteners it would not be acceptable though.

I've seen "magnetic mounting" systems, such as those integrated by Technomagnete and I'm wondering if anyone has heard of these being used to mount fixtures on electrodynamic shakers? The two concerns I see are the magnetic field of the mounting equipment interfering with the shaker operation...

Does anyone have experience with Omega's wireless transducers? I'm looking at the temperature, relative humidity, and pressure transducers to possibly replace chart recorders and keep a history of laboratory test equipment environments. I'm concerned about how well the OPC Server software...