Permanent magnet custom motors

From your needs to optimal solutions – together

We manufacture permanent magnet motors and generators designed for the needs of our customers. In every case, the dimensioning and manufacture of these machines takes account of the customer’s needs. Due to their excellent adaptability and structural characteristics, Randax electric motors and generators are suitable for a wide range of uses and conditions. These permanent magnet motors and generators are easy to integrate with the driven equipment.We manufacture permanent magnet motors and generators designed for the needs of our customers. In every case, the dimensioning and manufacture of these machines takes account of the customer’s needs. Due to their excellent adaptability and structural characteristics, Randax electric motors and generators are suitable for a wide range of uses and conditions. These permanent magnet motors and generators are easy to integrate with the driven equipment.

Randax® electrical machines are tailored according to the requirements of the customer and the application, providing the customer with freedom in product design. In every case, this means that the frame materials, connecting flanges etc. are specified in cooperation with the customer.

The motors or generators are based on permanent magnet technology and are always controlled by frequency converters. Their efficiency is always in the highest category, and they are available in water or air-cooled versions.

The power and speed of the motor are always designed according to customer requirements without limitations.

Propulsion motors

Randax has developed wide series of compact size and low weight liquid-cooled PM motors for electric propulsion. Power range is 10 – 3 000 kW and motors are to be used for electric or hybrid propulsion of the ships and boats. Randax® PM propulsion motor can be delivered with normal solid shaft or hollow shaft and always includes customized connection flange and mounting accessories.

Randax® PM propulsion motors can be used as a direct drive motor for speed level of 300 – 1 200 rpm or with the gear for 1 500 – 2 500 rpm speeds. Randax motor can be also delivered as a customized Stator & Rotor unit, which can be installed to customers’ existing propulsion pod frame.

More detailed technical specification about the each motor is provided within the case by case offer.

Benefits of Randax® PM propulsion motor:

  • Compact size and low weight due to PM technology
  • More reliable and less maintenance due to direct drive integration to driven equipment
  • Customized frame and materials to withstand harsh conditions
  • Customized Stator & Rotor units which can be installed to customers’ existing frame / propulsion pod
  • Water tightness is guaranteed by VPI treatment for all stator-rotor components and epoxy resin filling for stator windings
  • All coolant options available according to customer need, e.g. surrounding water can work as a cooling media

Blower motors

Randax has developed many advanced and innovative motor and generator solutions for blowers, compressors and renewable power generation applications. Solutions with power range of 10 – 500 kW and speed range of 500 – 10 000 rpm. Motors are equipped with steel or aluminum frame or air or liquid cooling.


Hermetic nitrogen blower motor

Randax has developed a hermetic nitrogen blower for Maillefer Oy, a global market leader in cable manufacturing equipment and systems. Nitrogen gas is used in the cable manufacturing process as a shielding gas, for example. The nitrogen blower transfers the nitrogen gas at a pressure of approx. 10 bar to the necessary points of the cable manufacturing process. The gas is at high pressure and contains small molecules, which sets high requirements for the blower.

A high operating pressure requires a blower with a rigid structure, and the connections need to be tight in order to avoid leaks. The nitrogen blower is a key component in the cable manufacturing process.

In conventional blower solutions, continuous servicing has been required to ensure the durability and reliability of the dynamic seal, since the blower impeller is routed through the pressurised space and closed off with the seal. The blower motor has been located outside the pressurised space at atmospheric pressure.

The newly developed Randax® blower motor completely eliminates the need for a dynamic seal. The motor has been made hermetic and pressure resistant, which allows the process gas to enter it.


  •  High reliability, no maintenance 
  • No dynamic seal and related lubrication systems
  • Extremely quiet and stable operation 
  • Rigid bearings and robust structure
  • Energy-efficient 
  • Permanent magnet motor with high efficiency and no dynamic seal and related energy waste

Special motors for equipment manufacturers

Randax motors are always designed for customer needs, taking account of the process’s special requirements and the customer’s equipment interfaces, while lowering overall product costs!

Randax motors are having very high efficiency level and they can be fully integrated as a part of customer’s equipment. Compact size and light weight of motors help to reduce the size of customer’s equipment and keep them down to a logistically reasonable size!


Hollow shaft PM motor series for aluminum induction heater

Randax has developed new hollow shaft motor series for Shanghai Realman Energy Technology Co., Ltd (SHRET), long term client and partner of Randax in China. During 2018 SHRET has developed new state-of-art permanent magnet induction heater for aluminum extrusion called R-PM Heater.

New R-PM Heater is very efficient and is using 25 % – 40 % less power compared to the conventional heating methods. In R-PMH electricity is used only for automation and to run the PM Motor with hollow shaft. Aluminum heating itself is done by rotating heating permanent magnets inside the hollow shaft.

SHRET has used Randax PM motors in their aluminum induction heaters already since 2014, so Randax was natural choice for developing the new type of heater motors as well. New R-PM Heater is using hollow shaft motors developed by Randax. Motors types and power levels are as follows:

  • 178kW@1000rpm
  • 240kW@850rpm
  • 340kW@700rpm

Motors are having unique design with aluminum frame including both water- and aircooling. Hollow shafts are very large with diameter of 340 mm and 520 mm while frame diameters are 900 mm and 1190 mm. Large hollow shaft is used for connecting the heating magnets in and aluminum billets are heated by rotating heating magnets inside the hollow shaft.

Compact and high efficient Randax motors enables R-PM Heater to be most efficient choice in aluminum extrusion market and to keep the overall equipment size at a reasonable level.

Pump motors

Randax has wide selection of advanced motor solutions for various different pump applications. Solutions are generally direct drive motors for power range of 10 – 3 000 kW and speed range of 100 – 5000 rpm. Randax supplies complete motors and also customized stator – rotor units (SRU) to be integrated into customers’ existing pump frame.

Motors are equipped with steel or aluminum frame and with air or liquid cooling. High efficiency Randax motors are always tailored for the customer’s application. Due to compact size and light weight of Randax motor or SRU, they can be fully integrated as a part of customer’s equipment.


Submersible dredging pump motor 1400kW@360rpm

Randax has developed and delivered stator – rotor units in size of 1400kW@360rpm for dredging pump application. This stator-rotor unit has been installed to submersible dredging pump motor frame made by Marotechniek. Marotechniek is Randax customer and partner in the Netherlands. This Permanent Magnet motor will be used in direct drive submersed dredge pump which will be installed on hopper dredger ship built by Damen shipyards.

The 1400 kW size electric motor is the world largest Permanent Magnet motor used in a submersed dredge pump drive to date. The air filled motor is smaller, lighter and more efficient than conventional asynchronous oil filled ones – with a staggering measured very high efficiency of 97% including friction of all bearings and mechanical-seal.

The hopper dredger is designed for mining marine aggregates at -55 m below sea level. The submersed dredge pump is directly driven by a continuous electric motor – that is, without a gear box in between. Moreover, the electric motor forms an integral part of the trailing pipe structure.

Both Randax and Marotechniek are expecting in near future huge growth in a market for submersible dredging pump motors.

Roll motors

The roll motor developed by Randax is ideal for use as a direct drive motor on the spreader rolls of paper machines. This roll motor innovation is a prime example of an integrated special motor and the related benefits. The patent is pending for the motor solution in several countries.

The energy-efficient and compact roll motor makes use of the spreader roll’s bearings. It is installed between the roll sleeve and the supporting articulated bearing, i.e. in place of the belt drive used in traditional solutions. The rotor of the direct drive Randax motor is directly supported by the rotating sleeve of the spreader roll and its bearings. The stator and the motor frame are attached to the static shaft of the roll.

The fully developed Randax® direct drive motor solution provides the user with numerous benefits:

Precise motor speed adjustment ensures good spreading efficiency and high-end product quality

  • Optimal spreading improves the operability of the paper machine!
  • The direct drive synchronous motor means that the roll rotates at exactly the same speed as the motor – no belt drive problems!

A maintenance-free motor reduces operating costs

  • The direct drive solution eliminates the need for belt drive servicing and adjustment!
  • The motor has no bearings – so there is no need for greasing!

The direct drive roll is delivered as a complete unit

  • The motor comes pre-installed when the roll arrives at the factory or is installed in the paper machine!
  • It is supported by the roll, which means that no separate adjustment platforms or foundations are required!

Benefits of using a special motor

  • The compact permanent magnet motor fits inside cramped spaces
  • High efficiency – energy savings
  • Corrosion-resistant materials for demanding environments

Contact Us:

Kimmo Huurinainen
Product Development / Sales
Tel. +358 44 734 6227

Kalle Holappa
Production Manager / Purchasing
Tel. +358 44 734 6311

Berend Muis
Netherlands, Belgium, Germany & UK
Tel. +31 6 22 40 75 74 ‌