Question about using run/start capacitors
This is for any electricians versed in the use of load and run capacitors to help with ac surges on the genny or the inverter. I am in the middle of a teardrop build and I am trying to get away wi...
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MEXICOWANDERER wrote:
The problem with live digital to capture peak events is the sampling rate per second.
If it's "too slow" it'll never see the peak as it passes over its head.
If it's too fast, changing numbers for instant updates turn the numeric segments into a blur.
To rate high speed sampling it takes a processor and enough random access memory. It would be a real eyebrow raiser to see that in an inexpensive device.
My Columbia analog meter uses a (something like) 9 jewel D'Arsonval movement of extremely low mass to minimize inertial lag and over run. "Warning Hermetically Sealed" can still be made out of the case halves seal. This was a pricey instrument in the 1940's. Supposedly has its origin in Hanford, WA. The meter is now encased in 2" charcoal gray block foam. The pickup was a killer. Two hundred dollars from Meter Master. Back in the late 1980's. The 2" loop diameter allows for compound wire winding for 2x 4x 8x. One of my treasured no-touchee gizmos.
Even with all that the meter is not precise. It can only give a rough approximation of inrush current. I would love to find an instrument that is digital, has max min storage and re-call. That and a peak-to-peak meter.
Dream-On Mex
very good summary of measurements. And the Tek power analyzer is one nice piece of equipment.
many of the newer quality meters (e.g. not low cost by any means) have a "Peak Hold" function which will display the peak reading. Some even have min-max-avg functions.
When I measured by starting current with the micro air I used a Tektronix clamp on current probe, NIST traceable cal that had the peak hold function.
On the Mach III on my trailer locked rotor amps were near 60A, while peak current with the micro air was 20A or less. I measured with each "learn cycle" that micro air has you do, and the first cycle was near 60A, by the 4th it was down to 20A.
And the meter sample interval was 10ms, so at 60hz, it should have captured the true peak current.
Meanwhile again using a Tek true RMS DMM I measured the honda 2000 Voltage during startup with the microair looking for the min voltage. Don't have the exact data, but from what I recall, it didn't drop below 110V during startup then settled to only a few volts under 0 load voltage.
