NTK 100 KW Wind Turbine

Nordtank 150 Nordtank 150 Nordtank 150

Technical Overview

EMI's "NTK 100" is a refurbished Nordtank 150, utilizing modern day controls and systems to create a reliable, like-new wind turbine, with a projected 30+ year life.

The NTK is a modified 150 KW wind turbine whereby the generator has been converted from a 4-pole @ 1,800 RPM generator to a 6-pole @ 1,200 RPM generator.

The Nordtank series of wind turbines were originally developed in Denmark.The same Nordtank turbine (fixed speed) operating in the USA at 1,800 RPM operates in Europe at 1,500 RPM due to the European grid operating at 50 Hz vs 60 Hz (USA). Original optimum operating performance and reliability for the Nordtank was for 1,500 RPM.

The originally designed NTK 65 has a 1,200 RPM generator and is capable of producing in excess of 65KW of electricity in strong wind conditions. The NTK 40 version offered by EMI is a de-rated version of the NTK 65, utilizing an 8-pole, 900 RPM generator.

Advantages of EMI's De-Rated “NTK 100”:

  1. Removal of the Integrated Gearbox Fan and addition of external oil cooler
    1. Fan removal increases bearing life by limiting balance issues
    2. Quieter operation by eliminating fan noise
    3. Increased electricity generation by approximately 3 KW due to fan drag elimination
    4. Filtration of gear lube oil
    5. Maintains constant operating temperature of the gear lube regardless of season (135-140 degrees F)
    6. Added oil reservoir and breather for visual oil level inspection

  2. Generator Update:
    1. Conversion from 4-pole to 6 pole though a rewind overhaul
    2. De-rated generator to 100 KW
    3. Replace generator bearings
    4. Modification to allow filtered outside air for cooling (open, drip proof)
    5. Removal of generator external fan
      1. Increases electricity output by as much as 3 KW
      2. Eliminates balance issues that cause premature failure of the generator bearings
      3. Quieter operation

EMI's "NTK 100" is equipped with the EMI-WTC (Wind Turbine Controller) that allows for monitoring and control from a Windows PC, Android App or IPad/IPhone App. The controller has two customizable options, Fixed and Variable speed.

Fixed Speed:

The fixed speed controller provides a fixed operating speed on the high speed shaft of 1,200 RPM. The lower speed reduces stresses and centrifugal forces on the blades by over 50% as compared to operating at 1,800 RPM. The lower speed enables electricity to be produced in light wind conditions, with wind speeds as low as 6Mph. Maximum output is limited to 80 KW based upon the blade stall characteristics turning at a slower speed. The fixed speed controller requires direct grid connection and grid reactive power for operation. See EMI-WTC data sheet for controller details.

Variable Speed:

The variable speed controller functions autonomously from the grid and can operate in both grid tie or off grid (Micro-Grid) environments. Variable speed uses elaborate control systems to generate power, using Self Excitation Induction Generator technology (SEIG) to produce electricity and manage speed. Furthermore, the controller manages power output (voltage) through speed control. The controlled speed varies between 900 RPM and 1,500 RPM depending on wind speed, electricity needs and power regulation. The turbine controller allows the turbine to operate at reduced speed in strong wind environments without the need to shut down (i.e. wind speeds in excess of 50 mph). Dynamic braking complements the mechanical brake.

In micro grid environments the controller is further controlled by a Master Micro Grid Controller (MMGC), which limits the automated controls in a process of managing micro grid voltage and excess power production. Typically MMGC environments are where more than 1 wind turbine is operating in an off grid environment and is part of a larger overall SCADA network. Contact EMI for custom SCADA solutions.

The variable speed controller will be available 3Q, 2016.

Automation Tie In:

Whether a turbine operates with fixed or variable speed, the controller integrates into an overall energy management system with EMI's Automation Tie In. Users manage the wind turbine and automate certain processes to run or stop, based upon electrical output levels. Automation Tie In adds little cost to the controller but produces significant cost savings by using locally produced electricity first vs. buying retail. Automation also manages expensive electricity demand charges. Depending on the application, the Automation Tie In feature can double one's net value received from each wind turbine.


Refurbished blades are overhauled to "as new" condition.  Cracks and other defects are repaired, not patched.  The blades have a proven track record and by slowing the turbine from a constant speed (1800 RPM) to maximum 1500 RPM, it significantly increases the life between blade overhauls.  The blade overhaul time is extended beyond 25 years.  EMI provides two blade types (Stork or Aerostar).  All blades incorporate tip brakes that deploy in the event of an overspeed condition.

  1. Stork Blades:
    Stork blades are refurbished and a replacement tip is made by EMI to reflect improvements in the design. A passive hydraulic accumulator provides fail-safe tip deployment as the centrifugal force (tip weight) exceeds the hydraulic force holding the tips in.
  2. Aerostar Blades:
    Aerostar uses a mechanical spring mechanism for tip deployment. Tip reliability is enhanced by the slower operating speed and has been the choice blade by past operators. Aerostar blades weigh more than the stork blades but offer similar performance

NTK 100 Turbine Pricing

1200 RPM Fix Speed
1200 RPM Variable Speed

Pricing does not include shipping or installation. Both can be provided and are subject to project scope and logistics. Freight on board Texas.



  • 100 KW
  • 1,200 RPM
  • 3 Phase, 480VAC, 60Hz

Controller: EMI-WTC

  • EMI-WTC: Customized Controller for energy optimization
  • I-Phone/I-Pad App HMI
  • Automation & Energy Management
  • Near Zero Power Consumption
  • Integrated Meter for Fault Monitoring


  • 3 Section Hot-dip galvanized Tubular steel
  • Top and Bottom access doors
  • Height – Hub 80' (with base)
  • Interior tower ladder with nacelle access


  • 3 fixed pitch, upwind
  • 64' diameter


  • Fiberglass reinforced polyester
  • Stork and Aerostar
  • Swept area: 3,278'

Operational Data: (Varies based on customized controls)

  • Standstill cut in wind speed: 8.5mph; with production to 6mph
  • Cut-off wind speed: None – stall regulated


  • Tower (3 sections total) 14,100 lbs
  • Nacelle, Blade, Rotor and Bedplate total 9,300 lbs