220.127.116.11 Reverse polarity protection. - The inverter shall be inherently pro-
tected against applied input voltage of reverse polarity.
18.104.22.168 Short circuit and overload protection. - The inverter shall utilize
automatic reset self-protective methods against short circuits and overloads in
excess of 150% of the full load (150VA). Fuses shall not be used.
3.6.2 Isolation. - The inverter housing shall be at ground potential.
3.6.3 Insulation resistance. - Unless otherwise specified on applicable
drawings, all insulation between electrically isolated circuits shall have a
minimum resistance of 100 megohms with 500 vdc applied.
3.6.4 Dielectric strength. - There shall be no puncture of insulation, no
sparkover, or decrease in dielectric strength when insulated areas, that are
electrically isolated from ground and from each other, are subjected to an ac
root mean square (rms) potential of 1000 v plus twice the rated voltage at 60 cps
for a period of not less than 3 seconds nor more than 5 seconds.
3.7 Performance. - The inverter shall meet the requirements of 3.7.1 thru
3.7.6 without spasmodic or intermittent operation with an input voltage of 24 + 6 vdc.
The voltage shall be applied to input terminals D and E, which shall be positive
with respect to terminal B. All terminal desgnations are those shown on Drawing
3.7.1 Input voltage surge. - The inverter shall show no evidence of physical
or electrical damage and shall exhibit no increase in output voltage after being
subjected to five dc voltage spikes of 80 volts each for 125 + 25 milliseconds at the
rate of 5 spikes per minute.
3.7.2 Output voltage. - The inverter shall have a regulated nominal ac output
voltage of 115 v rms.
3.7.3 Output voltage regulation. - The inverter output voltage regulation shall
be + 5% for any combination of load variation from no load to full load (150VA).
3.7.4 Output frequency. - The inverter output sinusoidal wave frequency shall
be 400 cps + 1%.
3.7.5 Harmonic distortion. - The inverter output shallbe free of electrical
voltage spikes and shall have a harmonic distortion of less than 4% for all loads and
all power factor ranges between 0.8 leading and 0. 6 lagging. With a constant
nominal unity power factor and at a nominal load of 75 VA the maximum variation of
harmonic distortion shall be 1.1.5%.