Power supplies designed for military ground vehicle applications must meet the MIL-STD-1275E standard requirements. Although these power supplies are primarily used in ground defense power systems, they can also be used by civilian manufacturers of heavy equipment and off-road vehicles that require robust and reliable power supplies. And since ground vehicles are often deployed in humid, dusty, or sandy conditions, the design of any MIL-STD-1275 power supply must take into account these environmental concerns. Hardware configuration must also be able to withstand the shock and vibration associated with travel in rough terrain.

What is MIL-STD-1275?

MIL-STD-1275 describes the 28Vdc characteristics, common across military ground vehicles, at the input terminals of electrical or electronic equipment connected to the distribution network. It lays the groundwork for commonality across vehicle platforms. The power system designers must ensure that the 28Vdc delivered to the utilization equipment meets the standard, whereas the utilization equipment designers must ensure their equipment will operate properly when connected to the power distribution network.

The MIL-STD-1275A standard was issued in September 1976 to establish several requirements dealing with spike, steady-state conditions, surges, and ripple of ground vehicle power sources. They were meant to supplement the requirements for MIL-STD-461 compliance for power systems and utilization equipment. The procuring authority was required to define how the equipment should operate during and after any disturbance in the power supply.

The revision to MIL-STD-1275B was released in November 1997, updating the requirements, and including limits for fault conditions for evaluation.

In June 2006, MIL-STD-1275C was issued to update the requirements and include a marked difference in the temperature range requirements for compliance. The new evaluation temperature range was set at
-45°C to +82°C from the previous range of -32°C to +52°C. Additionally, there were multiple references to SAE standards added to deal with EMC and supplement MIL-STD-461 requirements. For example, ESD testing that was not a requirement in MIL-STD-461 was introduced. However, vehicle power systems were exempted from conducted emission compliance to MIL-STD-461.

MIL-STD-1275D was issued in August 2006 with a few changes in requirements and definitions. It notably reinstated the temperature range evaluation of -32°C to +52°C. Additionally, the vehicle power system exemption for conducted emission compliance was updated to exempt only CE102 compliance.

In March 2013, the current revision MIL-STD-1275E was issued. The evaluation temperature range was established as ambient (+23°C ±5°C). However, it provided for extreme temperature evaluations as deemed fit by the approving authority.

Why Choose a MIL-STD-1275 Compliant Power Supply?

MIL-STD-1275-compliant power supplies are designed to meet the stringent requirements of military ground vehicle operations including starting disturbances, transients, surges and spikes. The requirements can be equally well applied to civilian applications, for example, off-road vehicles and heavy commercial equipment or any other type of vehicle which requires a reliable, regulated voltage source. A MIL-STD-1275 compliant power supply will offer an electrically robust solution capable of handling all the characteristics of a vehicle power distribution network.

Some of the benefits of a MIL-STD-1275E ground defense power system include the following:

  • Operation during initial engagement and cranking surges which occur during vehicle start-up
  • Operation with a steady state input voltage of 20V to 33V
  • Will tolerate injected spikes and not emit spikes greater than those permitted by the standard
  • Will tolerate injected surges and not emit surges greater than those permitted by the standard
  • Reverse polarity protection
  • Robust electrical performance for use in highly demanding applications
  • Superior EMI/RFI management and control

Whether you need an off-the-shelf or modifiable power supply for military ground vehicles, opting for a MIL-STD-1275 power supply guarantees robust electrical performance with maximum compatibility across vehicle platforms.

Characteristics of a MIL-STD-1275 Power Supply?

The MIL-STD 1275E is an immunity standard that defines various test conditions to be applied to 28V equipment used within a military vehicle. These include operating voltages, transients, surges, spikes and ripples.

Here is a quick overview of the characteristics of a MIL-STD-1275E-compliant power supply:

  • Voltage Requirements:
    • Steady-state operation across the voltage range 20 to 33 VDC.
    • Operation during initial engagement, 12V for up to 1s.
    • Operation during cranking surges at start up, 16V for up to 30s.
  • Transient Disturbance Requirements:
    • Tolerate applied surges, and not emit surges in excess of the following:
      • 100V for 50ms down to 33V for 500ms
      • 18V for 500ms up to 20V for 600ms.
      • Single injected surge energy of 60J maximum
    • Tolerate injected spikes, and not emit spikes in excess of the following:
      • +250V for 70µs down to 100V for 1ms
      • -250V for 70µs up to 18V for 1ms
      • Single injected spike energy of 2J maximum
      • Single emitted spike energy of 125mJ maximum
    • Reverse Polarity Requirements:
      • With maximum steady state voltage applied for 5 minutes, reverse current does not exceed the normal operating current.
    • EMC and ESD Requirements, per MIL-STD-461:
      • Lightning induced voltage spikes
      • Electromagnetic pulses
      • Power switching
      • Electrostatic discharge

Summary

MIL-STD-1275 requirements deal with ground vehicle power characteristics for both power distribution and utilization equipment. Compliance to the standard maximizes compatibility across vehicle platforms.

At Viable Power, we offer customized power solutions for military sectors, such as naval, ground defense, and aerospace. All our ground defense products meet the strict electrical performance requirements of MIL-STD-1275. Additionally, our MIL-STD-1275 power supplies are ruggedized to ensure operation in harsh environments common in military applications, such as high vibration, heat, and humidity.

We understand that the ground defense sector has very specific requirements for the design of DC power supplies. As a military power supply manufacturer, Viable is able to design rugged DC-DC power supplies that meet the requirements of MIL-STD-1275. Please contact us for more information on our products and services.

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