Variable Speed Drives
Berges Antriebstechnik GmbH & Co.KG (Germany)
BERGES is one of the world's leading suppliers of mechanical infinitely variable pulley systems.
Their extensive range of ready-to-install components covers a power range of 0.25 up to 200 kW.
For many applications, mechanical pulley technology is the easiest and most solid alternative to sensitive electronics.
Normal or wide V-belt technology, single- or double pulley drives, spring or cam pulleys, ready-to-fit RGAE assembly units, supplementable with 3-phase A.C. motors and reduction gear boxes, for nearly every application the right solution is already available in BERGES's standard range.
Double pulley type RFb and RDb for wide belts up to 160 kW motor power. Double pulley drives type KRM, RF for standard belts.
Single pulley type Fsb for wide belts up to 55 kW motor power. Single pulley drives type KM, Fs for standard belts.
Symmetrical pulley technology up to 160 kW
- V-shaped, symmetrical cross-section
- Uniform flank contact forces
- High power transmission with low mass
Double pulley drive RF b for wide V-belts
A mechanical variable pulley Rb. mounted on the driving shaft (motor shaft) and a spring-loaded variable pulley Fb, mounted on the driven shaft* form a variable pulley set with fixed centre distance RF b. Also suitable for reversing operation.
Double pulley drive RD b for wide V-belts
This pulley set has a torque-dependent control cam in addition to the pressure springs to absorb intermittent overloading or torque peaks.
Double pulley drive KRM, RF for standard V-belts
These pulley sets are designed for use with standard V-belts in special applications. The KRM type pulleys are designed as plain pulleys and RF types with interlacing pulley sheaves.
Speed adjustment controls for double pulley drives
The variable pulley and control device are mounted together centrally on the drive shaft. This arrangement has the advantage that there are no additional axial loads on the motor shaft bearing.
Single pulley drives Fsb for wide V-belts
In this system, a spring pulley which opens on both sides (Fsb) is used in conjunction with a fixed driven pulley. Speed adjustment takes place by adjusting the center distance by way of the motor carriage or tilting base.
Single pulley drives KM, Fs for standard V-belts
A fixed driven pulley is required in each case for use with these single pulley drives for standard V-belts. The spring-loaded variable pulley can be opened either on one side (KM) as a plain pulley or on both sides (Fs) as an interlacing type pulley.
Asymmetrically variable speed pulleys up to 200 kW
- Asymmetrical cross section
- High power transmission up to 200kW
- Low belt-warming
- Asymmetrical V-belts have a lower belt volume and thus for higher lateral rigidity and less heating, resulting in higher load capacity and longer service life
- Asymmetric output pulleys are also available with torque-dependent pressure cams, which automatically and permanently guarantees the optimum axial pressure of the V-belt and thus prevents belt slippage during peak- and overload operation or machine starts.
By taking over the asymmetric adjustable pulley technology from the company Becker Antriebe, Sinn, BERGES has significantly expanded its field of competence. BERGES is the only supplier worldwide to offer the two existing variations in design: both the symmetric and as well the asymmetric pulley-type technology.
Single pulley drives FG
Asymmetrical drive units FG for 0,75 – 45 kW motor ratings, comprising:
- Spring-loaded regulating pulley F mounted on the motor shaft
- Fixed-diameter driven pulley mounted on the machine or gear shaft.
The axial pressure on the V-belts is exerted by compression springs with optimally dimensioned characteristics. Speed variation is achieved by changing the centre-to-centre distance by means of a sliding motor base plate. Speed variation within ratio of 1 : 3. This system provides a high torque at a low output speed.
Single pulley drives GF
Asymmetrical drive units FG for 1,1 – 45 kW motor ratings, comprising:
- Fixed-diameter driven pulley mounted on the motor shaft
- Spring-loaded regulating pulley F mounted on the machine or gear shaft
The axial pressure on the V-belts is exerted by compression springs with optimally dimensioned characteristics. Speed variation is achieved by changing the centre-to-centre distance by means of a sliding motor base plate. Speed variation within ratio of 1 : 3. This system provides an almost constant output power over the complete
Double pulley drive RF, RFN
Asymmetrical drive units RF, RFN for 0,37 – 45 kW motor ratings, comprising:
- Mechanically adjustable regulating pulley R with integral central adjustment
- Spring-loaded regulating pulley F
- Type FN with increased diameter for lower output speeds
The axial pressure on the V-belts is exerted by compression springs with optimally dimensioned characteristics. This driving system is suitable for reversing operation.
Double pulley drive RK, RKN
Asymmetrical drive units RK, RKN for 4 – 150 kW motor ratings, comprising:
- mechanically adjustable regulating pulley R with integral central adjustment
- Output pulley K with automatic torque-dependent pressure device
- Type KN with increased pulley diameter for lower output speeds
This driving system is characterized by high efficiency even with partial load operation. This driving system is suitable for high starting torques and provides a high degree of overload safety.
Assembly units RGAE
Assembly units of the type RGAE – consisting of a housing, variable pulleys and wide V-belt – are designed for mounting on motors and reduction gearboxes according to IEC standards.
RGAE assembly units are additionally equipped with step or flange bearings and two-bearing shafts (gearbox flange). They are suitable for use with any drive elements as well as for direct mounting of gearboxes with IEC connection.
These assembly units are available complete with adjustment controls, motors and reduction gearboxes if required.
Variable speed gear motors
Available in any combination of drive type and motor design. Let us know the job at issue and we will be happy to work out an individual solution for you.
ATEX variable speed gear motors
These variable drive motors are explosion-proofed according to directive 2014/34/EU and they classified for Device Group II in Categories 2 and 3 EX II G D c T4 135°. They are available with either reduction gear or gearbox flange.