Var-Spe HydroDynamic Speed Variators

Introduction to Var-Spe

Giuseppe Speggiorin, founder of Var-Spe and the inventor of the hydrodynamic speed variator, was born in 1924 in the province of Vicenza, Italy. His passion for mechanics was born in the post-war period when he went to work for a company specialising in the repair of airplane engines. He was fascinated with speed variation in industrial processes and recognized the growing need in the market to adapt the speed of motors to production processes. This marked the beginning of a long history at Var-Spe for technological innovation that continues today.

Introduction to Hydrodynamic Speed Variators

The technology invented and patented by Var-Spe involves varying the speed of an electric motor through an innovative approach that is completely different from that of all other alternative solutions.

Speed is varied physically by exploiting the properties of fluid and without electricity. The Var-Spe technology is based on the principle of hydrostatic transmission.  It consists of two units including a variable displacement pump and a fixed displacement hydraulic motor, both with radial pistons. The input shaft transmits the constant speed of the upstream motor to a series of pistons that compress and expand the oil inside the cylinders. By varying the oil flow rate and pressure, the speed of rotation transmitted to the output shaft is varied as well.


• High torque even at low revolutions
• Wide range of speed variation from zero to the limits of electric motor
• Operation in aggressive and corrosive environments including water, dust, temperature and acid
• Long service life as there is no friction elements and components are less subject to wear
• Reliability
• Precise speed adjustment done by modifying the stroke of the pistons
• Adjustments on-the-fly are possible including zero rpm with the motor running
• Cost-effectiveness and long life as the electric motor is always running at same speed
• Adjustment is simple and intuitive, no programming needed
• Easy to install and start


• Available in power ranges from 0.37 kW to 22kW
• Zero rpm output with the motor running
• Adjustment handwheel even with the motor off
• Linearity between handwheel turns and output speed
• Available in horizontal and vertical installation positions
• Precise and repeatable adjustment even after a very long time (no internal friction element)
• Speed limiter available
• Clockwise and counter-clockwise output rotation
• Manual and remote-controlled speed adjustment systems
• 100% Italian-made including all components
• Top quality material
• Full in-plant inspection for every unit

Typical Applications

The Var-Spe speed variator is suitable for many types of applications and sectors due to the wide speed range, high torque at low speed, sturdiness, reliability, resistance to pressure and use in tough environments. Typical applications include:

• Conveyors (belt, chain, rolls)
• Feed screws
• Dosing systems
• Pumps and mixers
• Winding and unwinding systems
• Quarries and Stone
• Food / Pharmaceutical
• Chemical, Oil and Gas
• Wood Processing
• Waste treatment

Also Available - ATEX-certified Variators for Explosive Environments

The Var-Spe variator is the ideal solution for potentially explosive and explosion-proof environments in compliance with the Atex 95 directive (94/9/EC). They are simple, sturdy and reliable. Thanks to hydrostatic technology, they need do not require complicated and expensive monitoring devices. All Var-Spe products can be supplied in accordance with the ATEX directive.  For Atex Zone 1/21 or zone 2/22 environments, both gas and dust, according to the following classifications:

• Ex II 2 GDbc IP65 T135°C X
• Ex II 2 GDc IP65 T180°C
• Ex II 3 GDc IP65 T135°C

For additional information, please contact Application Support.

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