Hi All,
Twice in a week must be some sort of record
for me but I think the question about surge capability and who has the most
muscle is being oversimplified here. The "raw numbers" posted here don't take
into account the AC voltage at the time the surge currents are being produced.
Some machines, such as the SW5548 have much tighter AC voltage windows and will
not allow the inverter output voltage to sag but a few volts. Others such as the
notable 3624 will produce huge amounts of raw current with pretty wide voltage
drops on startup. In a very real way, the quality of power being delivered when
the inverter is "surging" is a design choice.
I got some help from our Engineering department and they produced the following explanation and table
Here are 5 second surge ratings with the AC output voltage measured at the end of the 5 second period. The load used was resistive (light bulbs) and the load was applied and quickly ramped (in about 1 second) from zero to the rated power via a large variac. The watts are "real" watts, measured with a Fluke 41B and a Power Tracer metering system. The battery bank consisted of sixteen L16 batteries with short 4/0 AWG battery cables. Actual field performance may be reduced by tripping of the battery breaker or blowing of the battery fuse depending upon its ratings and time delay characteristics.
MODEL RATED POWER VOLTAGE OUTPUT POWER @ OUTPUT VAC
DR1512 1500 watts 12 VDC 2400 watts @ 105 vac
DR1524 1500 watts 24 VDC 3600 watts @ 111 vac
DR2412 2400 watts 12 VDC 4200 watts @ 104 vac
DR2424 2400 watts 24 VDC 6200 watts @ 109 vac
DR3624 3600 watts 24 VDC 7500 watts @ 103 vac
SW4024 4000 watts 24 VDC 8000 watts @ 113 vac
SW4048 4000 watts 48 VDC 8800 watts @ 115 vac
SW5548 5500 watts 48 VDC 9500 watts @ 117 vac
This is very different than the normal 1 ms / 100 ms surge rating of amps and is better for understanding the ability of the different inverters to operate multiple AC loads. This does not represent motor start capabilities as this issue is more
complicated. I hope that this clarifies the subject of inverter surge behavior some.Best regards,
Ezra Auerbach
Xantrex Technology Inc.
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