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Q
Do Perseus fans withstand blowing sand and dust in desert environments?
APerseus fans are evaluated for sand and dust resistance (e.g., GJB 150.12A blowing sand and dust procedures) with IP67 sealing options for harsh outdoor use. Sealed construction and protected bearing designs help resist fine-particle ingress. Test results are reviewed against your specific environment; representative data is available on request.
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Q
Why can PWM speed control fail even when the fan is powered correctly?
ACommon causes include an incorrect PWM reference ground, reversed signal wiring, incompatible control voltage, an unintended external voltage divider, excessive cable noise, or a missing isolation strategy between digital ground and power return. In avionics or RF equipment, PWM wiring should be checked together with EMC planning, cable routing, and controller input protection.
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Q
How are Perseus cooling fans qualified for salt fog and seawater exposure on naval platforms?
AFor naval and shipboard applications, Perseus fans use sealed construction with corrosion-resistant materials and finishes. In representative testing, an evaluated configuration passed 1,000 hours of seawater immersion and 192-240 hours of salt-fog exposure cycles (pH 3.5 ± 0.5). IP67-sealed options are available. Qualification results are configuration- and platform-specific; contact our engineering team to review test data against your requirement.
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Q
How should replacement fan selection start when only a competitor model is known?
ABegin with the public datasheet or measured sample data for the existing fan: frame size, mounting pattern, voltage range, current, speed, airflow, static pressure, acoustic limit, connector or lead interface, PWM logic, and FG/RD output type. The replacement should then be checked against the system operating point, environmental requirements, and qualification plan rather than by size match alone.
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Q
Which environmental tests matter for naval, outdoor, or high-salt cooling applications?
ANaval and outdoor defense systems should review salt fog, humidity, rain, dust, vibration, shock, and corrosion protection together with the enclosure design. Useful planning references include MIL-STD-810H environmental methods and project-specific protection requirements such as IP rating, coating system, drainage, connector sealing, and maintenance access.
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Q
What should be checked when fan noise increases after installation?
ANoise after installation can increase because of inlet restriction, outlet obstruction, grille turbulence, structural resonance, incorrect mounting torque, unexpected PWM duty cycle, or operation near an unstable point on the P-Q curve. The review should compare free-air data with installed airflow, pressure drop, vibration path, and the actual mounting structure.
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Q
What PWM and feedback signals do 28VDC BLDC fans use?
APWM control and FG/RD feedback signals should be reviewed with the correct reference ground. The PWM control reference is normally tied to the fan negative return, and interface errors can cause unstable speed control, false fault feedback, or signal noise. FG feedback is used to monitor fan speed through pulse frequency, while RD feedback is used to monitor run or fault status. FG/RD outputs should normally be wired individually when independent fan monitoring is required.
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Q
How does altitude affect fan cooling performance?
AAt low pressure, volumetric airflow and cooling capacity should not be treated as the same value. Reduced air density lowers heat capacity per unit volume and changes pressure performance, so high-altitude fan selection should be reviewed by operating point, air density, thermal load, enclosure resistance, and model-specific speed behavior. For airborne or high-altitude electronics, low-pressure review may reference MIL-STD-810H Method 500.6 when the qualification plan requires altitude or low-pressure testing.
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Q
What is the correct way to read a fan P-Q curve?
AThe operating point of a cooling fan is the intersection between the fan P-Q curve and the system impedance curve. Free-air CFM describes airflow at zero static pressure, but installed airflow depends on filters, heat sinks, cable bundles, card guides, EMI screens, louvers, and duct geometry. To read a P-Q curve correctly, plot or estimate the system resistance curve on the same axes, find the intersection, and confirm that the resulting airflow meets the thermal budget with adequate margin.
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Q
How is a military cooling fan different from a commercial fan?
AA military cooling fan is selected by operating-point airflow, pressure capability, electrical interface, installation constraints, and environmental requirements, not by free-air CFM alone. In defense electronics, the correct fan is the one that can deliver the required airflow inside the real enclosure while remaining compatible with the applicable thermal, vibration, shock, altitude, and EMI conditions. Commercial fans are typically screened by free-air airflow and price, without the environmental qualification traceability that defense platforms require.
APerseus fans are evaluated for sand and dust resistance (e.g., GJB 150.12A blowing sand and dust procedures) with IP67 sealing options for harsh outdoor use. Sealed construction and protected bearing designs help resist fine-particle ingress. Test results are reviewed against your specific environment; representative data is available on request.
