Zefr 250W – Small Wind Turbine

Zefr wind turbines are the first wind turbines designed to be installed in an array. Zefr’s small, light-weight design results in easy integration into a variety of architectural landscapes, adding both power production and aesthetics to any project.

The Zefr Advantage

Zefr arrayed turbines have several key advantages when compared to similar wind turbines. Below we discuss these advantages and explain the reasons they would be considered as critical to building owners and their occupants.

Zefr is the first turbine that can be installed in an array using industry standard micro-inverters and racking systems and unlike many other turbines on the market, Zefr can keep producing power at wind speeds exceeding 35 mph.

Zefr turbines are designed to be installed in an array where instead of using a larger turbine with significant point-load problems, the turbines structural support is distributed over a larger surface area. In short, with Zefr, there is no point-load. This technique virtually eliminates building structural vibrations issue and is often the single most important reason our customers install Zefr.

High-Wind Production

In high wind areas, virtually all commercial wind turbines apply the ‘brake’ and expend the wind energy in the systems dump load.  This is clearly wasteful as high wind conditions represent the opportunity to generate a great deal of power as the wind goes up by the power of three i.e. the power contained in 30 MPH wind is twice as much as the power at 24 MPH.  Yet most wind turbines shut down once wind speeds exceed 25 MPH.

Zefr’s auto-furling mechanism provides it with the opportunity to continue to produce energy at wind speeds exceeding 35MPH. Once the wind speed exceeds 35MPH, unlike other turbines, it does not shut down but continue to produce power even though it auto-furls to protect itself against possible mechanical failures.

Industry-standard Grid Connectivity

One of the most challenging tasks of designing a wind turbine is the job of converting the power generated by the wind turbine to a format that is compatible with the standard grid so that the energy produced could be used to effectively turn the utility meter backwards.

Historically, the inverter is the most common reason for failure in wind turbines. Zefr turbines are equipped with industry-standard micro-inverters. These inverters are produced in millions of units every year and have proven to be extremely reliable and durable.

Industry-standard Installation Techniques

Zefr borrows from the PV Solar industry’s proven racking system. The racks, the hardware clips and the cabling are used commonly and are available from local distributors or from JLM. This makes the job of installing Zefr turbines simple and cost-effective.

Turbine Mounting Systems

Zefr offers several different types of mounting systems that give our turbines the flexibility to easily attach to various types of building surfaces. Turbines can be positioned as close as 5’ apart using our standard parapet mount and even closer, 3’ apart, utilizing our alternating parapet mounting system.


The advanced technology in the Zefr Wind Array Turbine System is the key to its success. Over the past several years, the engineers at JLM Energy have combined the fields of aerodynamics, power electronics and digital control to create the first wind array system. Pioneering technologies such as the Smart Gearbox, Breezebox, and Brakebox have made Zefr one of the most sophisticated wind turbine systems on the market.


Rated Power: 240 Watts at 35 MPH

Generator: 3-phase, rated at 500 Watts

Output Voltage Rating: 30V constant-voltage

Output Current Rating: up to 8 Amps

Approximate Product Weight: 35lbs

Brake: Electromagnetic