Thursday, March 7, 2013

Magnum / Splendide Photos

A   T&T forum member loaned me a current transformer as well as a 55uF run cap.  This morning I took a series of samples capturing current, voltage, and their phasing.  

Voltage (the top trace) is as displayed (50v / div)
Current (bottom trace) translates into  1V = 10A, and do note the scale was changed between screens.  To 'convert back':
  • 0.2v -->   2A / div
  • 0.5v -->   5A / div
  • 1v   -->  10A / div
Should also note that the current probe was placed between the Inverter and the Washer/dryer.  
When Caps were added, they were placed at the washer/dryer - so the current probe was then between the Inverter and the Caps / Washer-dryer.

All measurements were take at 2mS / Div, and was triggered on the rising edge of the Voltage waveform.



First off, lets look at the washer when it is on shore power:

Washer on Shore Power

Nice looking sine wave, with the current spikes where one would expect them.  I will note this was early in the washing cycle, perhaps things get more complex later on.

For fun, here is a capture of the Inverter powering a 750w space heater:
Inverter powering 750w resistive load.





Now lets look at an uncorrected (raw no Run Caps added) waveform from the inverter while powering the Splendide Washer / Dryer:
Inverter, no correction.  Notice start of hook.

Same, but accumulated waveform over 30 seconds or so.

Another ~30s block


We can see the hooking that seems associated with the washer/dryer faulting.  I do notice a bump in current just as the voltage starts to rise, and then it drops.  Perhaps this workload is what is confusing things?


And here we have some waveforms with the addition of a 15uF motor run cap:

Inverter + 15uF Run Cap

Inverter +15uF Run Cap, approx 30s accumulation


In these photos we can see the current spike is more pronounced on the rising edge of the Voltage (30s accumulation capture)    Do remember, the current probe is placed BETWEEN the inverter and the cap/washer-dryer. 




And finally, here is the same but using the 55uF cap as opposed to the 15uF.  (Will note, Magnum had recommended a 50uF cap as a solution):

Inverter + 55uF cap

Inverter  + 55uF cap, accumulated over approx 30s
 
Clearly that leading edge current spikes noticeable   And there seems to be a like spike on the falling edge as well, but perhaps not as large.  On the accumulated capture, converting the 0.2v/div into amps this raising edge spike is 7.6Ap, I can not see the negative one so can not really measure it.  But I estimate it to be 4.6Ap  But no hook in the voltage!  A bit flat topped perhaps, but no hook.


After this load of laundry finishes up I will run another series of measurements, I want to try and capture:
  • More detail in the Rising Edge current spike.
  • Additional shore power captures, esp during critical portion of washing cycle, not just the beginning.
  • Sampling with the current transformer placed between the 55uF cap and the washer/dryer.








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