Alter® SM 1250
Air-cooled Switch Mode Microwave Power Supply for 3kW, 2.45 GHz Magnetrons

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The SM 1250 magnetron power supply is a compact, air-cooled, switch-mode power supply designed to drive most nominal 3 kW @ 2.45 GHz magnetron models.

For power control versatility, depending on the model, the output power of the SM 1250 can be variably adjusted from 10 to 100% using an external 1 to 10 VDC analog signal, or by remote control through a fieldbus interface or by front panel commands.

Available in either 208 or 400 VAC line voltage configurations, the SM1250 is designed to power and control MKS, Alter Products TM031, TI031 or TX030 microwave magnetron heads; however it will also power other manufacturers electrically compatible heads. The compact and innovative design of the SM 1250 power supply make it a highly competitive alternative to traditional, transformer based, power supplies.

The SM 1250 autonomously manages the working status of the magnetron, providing signals to drive the correct pre-heating of the filament and to adjust the filament voltage according to the specific back down curve. In addition, the power supply automatically shuts off the output power in the event of an alarm condition, such as over current or over voltage of the magnetron.

The SM 1250 is packaged in a 19-inch wide, 3U high rack mount enclosure and is built with a rugged steel base and easily removable cover. Industry standard electrical connectors, dedicated to specific electrical functions, provide simple and easy set up. The power supply high voltage (HV) output, carrying the anodic current, is delivered through an HV connector with an insertion detection switch.

Features & Benefits:

  • High efficiency power supply design requires only air cooling - simplifies installation & reduces cost
  • Low output ripple - suitable for most applications
  • Advanced filament control for low maintenance and long magnetron life
  • Efficient power stage design for low harmonics and inrush current
  • "Plug & Play" design for fast & easy installation
  • Versions available for many applications


The SM 1250 is designed to drive most nominal 3 kW @ 2.45 GHz magnetron models.


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Part NumberPriceQTY
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Need help?

Contact an Applications Specialist by sending an email to MKS Instruments or call 978-284-4000.