Oscilloscope for Recording Transients
Oscilloscope for Recording Transients
(OP)
What is a decent resolution for recording transients created by closing in power factor correction capacitors; for example?
Also, what probes would best be used for connection? Voltage leads on a CT secondary, or clip on Hall-effect type probe?
I'm seeking a good hand-held type scope for troubleshooting nuisance trips and general power quality issues at one of our facilities. What bandwidth and sample rate would be best suited for power quality? Thanks in advance.
Also, what probes would best be used for connection? Voltage leads on a CT secondary, or clip on Hall-effect type probe?
I'm seeking a good hand-held type scope for troubleshooting nuisance trips and general power quality issues at one of our facilities. What bandwidth and sample rate would be best suited for power quality? Thanks in advance.






RE: Oscilloscope for Recording Transients
1. Resolution: Visit
http://www.laboratorytalk.com/news/gou/gou105.html
for: SVGA resolution
http://www.engineering.co.kr/test_homepage/main/main_fr...
for: A/D resolution: 8bit .39%
2.
A probe type depends on an application and transients.
3.
Visit
http://www.tti-test.com/products-resale/tek/tek-ths700....
for:bandwidth, and harmonics up to 31st
http://www.ferret.com.au/articles/0d/0c01000d.asp100MHz
etc. for more info
RE: Oscilloscope for Recording Transients
An oscillograph works the best but it is an analog type (read old) piece of equipment.
Astro-med has some great recorders that as well if not better than the old O-graph.
Digitally, a point every 10 to 100 micro-seconds. A digital oscilloscope should do the job, then dump it to Excel if you wish.
Suggest a Hall effect clamp on type. With some care it will provide accurate results.
I would be very careful with measuring the Vdrop on a CT. If it opens, your equipment is gone. Also you might inadvertantly cause a ground in the system.
I would look at the Fluke Scopes. They will hold up in some very bad environments. Mine is 100MHz
RE: Oscilloscope for Recording Transients
If you are measuring current, use a Tektronix AM503 series current probe and amplifier. The bandwidth is high enough not to matter (50MHz), and it will not introduce any phase error at frequencies of interest to a power engineer. Most CT's have lousy bandwidth and introduce phase and amplitude errors so don't use them unless you are backed in to a corner. The AM503 probes are expensive - rent one!
You could consider a Hall-effect probe from, as a suggestion, LEM-HEME. I have mixed feelings about these instruments. They are very good in the right environment, but I have also had some awful experiences with high dv/dt signals being capacitively coupled in to the output. Sometimes when a signal just looks 'wrong', you have to remember that the transducer isn't always blameless. The AM503 probes have never suffered this problem in my experience, but the absolute maximum ratings are just that. No tolerance, just a dead probe if you exceed the limit.
Your local instrument distributor should be able to get you a demo or loan instrument. See which feels best to you - much of value of an instrument is in the user interface, not the spec sheet.
RE: Oscilloscope for Recording Transients
http://www.abletron.com/Oscilloscopes.htm
for an Oscilloscope selection and parameters
RE: Oscilloscope for Recording Transients
TTFN
RE: Oscilloscope for Recording Transients
Have a really good play with the triggering facilities and make sure you can capture what you wish to see. Triggering on irregular waveforms and single-shot triggering was a nightmare with the early Philips Scopemeters (now part of Fluke). The later models are better. The Tek instruments were always good.