Background
The Chameleon ACP-1 has been tested for compatibility with an ungrounded single phase 115V 60 Hz Type I power as described in MIL-STD 1399 Section 300A, Change Notice 1. The module does not comply with all the subsections of the standard.
In general:
- The Chameleon ACP-1 power supply module can safely operate in the power environment described by MIL-STD 1399, Section 300A Change Notice 1 (i.e. the affect the power system has on the ACP-1).
- However, the ACP-1 does not meet certain tests intended to measure the affect the ACP-1 has on the power system . . . in those cases we believe that power draw from the Chameleon is insignificant when compared to the system, and as such, the effects of the non-compliant tests are also insignificant.
MIL-STD 1399 Tests the ACP-1 Does Meet
Fairmount Automation has indicated that the ACP-1 will operate properly in the following conditions as described in MIL-STD 1399, Section 300A Change Notice 1:
- Voltage and Frequency Tolerance
Characteristic Voltage (VAC) Frequency (Hz) Lower Limit 107 58.2 Nominal 115 60 Upper Limit 123 61.8 - Voltage and Frequency Transient
Characteristic Voltage Frequency Lower Limit 92 VAC 56.7 Hz Nominal 115 VAC 60 Hz Upper Limit 138 VAC 63.3 Hz Recovery Time 2 sec 2 sec - Voltage Spike
Characteristic Criteria Voltage spike (peak value, includes fundamental) 1,000V - Grounding
The unit will operate normally with one power input line grounded at a time.
Fairmount Automation has also indicated that the ACP-1 will survive the following conditions as described in MIL-STD 1399, Section 300A Change Notice 1:
- Emergency Condition
Characteristic Criteria Frequency excursion -100% to +12% Duration of frequency excursion Up to 2 minutes Voltage excursion -100% to +35% Duration of voltage excursion Up to 2 minutes
MIL-STD 1399 Tests the ACP-1 Does Not Meet
Based on past experience, the ACP-1 will not successfully meet the requirements of MIL-STD 1399 for the power demand profile and the current waveform:
- Power Factor Requirement: MIL-STD-1399, Section 300A Change Notice 1 specifies that user equipment has a power factor within range of 0.8 lagging to 0.95 leading per Section 5.2.6. This data is verified via the user equipment power profile test per Section 5.3.6 of MIL-STD-1399, Section 300A Change Notice 1. It is anticipated that the ACP-1 will have a power factor of approximately 0.6 lagging.
- Surge Current Ratio Requirement: MIL-STD-1399, Section 300A Change Notice 1 specifies that user equipment has a ratio of peak surge current to normal current as shown in Figure 14 of the standard. For devices consuming 3kW and under this ratio is limited to 10. Individually, the ACP-1 will draw a maximum of 35W and most likely will have a surge current ratio of that exceeds 10 (approximately 20 to 40) for a brief period during startup.
- Current Harmonic Requirement: MIL-STD-1399, Section 300A Change Notice 1 specifies that user equipment limits the harmonic line currents to less than 100/n of the unit's rated full load fundamental current per section 5.2.8. The table below shows ACP-1's performance under a typical load.
Harmonic # Harmonic Current Limit (% of fund cur) Unit harmonic Current (% of fund cur) 3rd 33.3 86.1 5th 20.0 64.0 7th 14.3 38.7 9th 11.1 16.5 13th 7.67 8.76 15th 6.67 8.97
Summary
It is important to realize that in most cases the Chameleon controllers use less than 35W. Since this total load is very small, it is expected that a load of this size that does not meet the power factor, current harmonic, and surge current requirements will not materially impact the operation of the ship's power system and other ship's systems.