8LV compact motors
Dynamic compact drives
The most modern machine concepts demand excellent dynamics and performance within the smallest amount of space possible. 8LV three-phase synchronous motors from B&R were specially developed for this area of application and provide users an extremely high power density for the highest level of support when designing machines.
8LV - Compact servo technology
When installing servo motors in extremely small spaces, the 8LV motor series from B&R is just what you need. Equipped with either a resolver or with highly modern EnDat 2.2 interface, these motors are ready to meet the highest demands. Through their low moment of inertia, the motors from the 8LV series are designed to be highly dynamic and are characterized by excellent self-acceleration properties. These motors have IP54 protection standard but are also available with IP65 protection. They are also available with an optional holding brake. Designed for use with ACOPOSmicro servo drives, these motors offer extremely high performance and are some of the most compact on the market. 8LV servo motors are recommended for a wide range of applications and provide an optimum price/performance ratio in the power range up to 1 kW.
Embedded parameter chip
Embedded parameter chip All relevant mechanical and electrical information and data is stored in the EnDat encoder used for the 8LV three-phase synchronous motors. This means that the user doesn't have to configure settings on the servo drive in the field. As soon as the encoder is connected to the servo drive and the power is applied to the electronics, the motor is automatically identified. The motor sends its rated parameters and limit parameters to the servo drive. The drive then automatically determines the current limits and current control parameters required for optimal control of the motor. The user only has to optimize the speed and position controller. The integrated start-up environment in B&R Automation Studio provides assistance. In addition to assistance during commissioning, routine service work is also simplified, and motors can be exchanged without having to take extra time to set parameters.
Cooling type and size
The self-cooling (cooling type A) 8LV servo motor series is available in three different sizes (1, 2, 3). They have different dimensions (especially flange dimensions) and power ratings. The various sizes are differentiated by a number (c) in the model number. The larger the number, the larger the flange dimensions and power rating for the respective motor.
The 8LV series is available in two different lengths. They have different power ratings with identical flange dimensions. The various lengths can be differentiated by a number (d) in the model number.
As for the encoder equipment, B&R offers a choice between a resolver for standard applications and absolute encoder with EnDat 2.2 interface. The ultra compact encoder with a length of less than 13 mm is multiturn-capable and has a battery backup system. With 262,144 (218) position values per revolution and 65,536 (216) distinct revolutions, the encoder provides excellent resolution in an extremely compact design.
Load capacity of the shaft end and bearings
8LV servo motors are equipped with grooved ball bearings which are sealed on both sides and greased. The radial and axial forces (Fr , Fa) that occur on the shaft end during operation and installation must be within the specifications listed below. The bearing elements must not be subject to shocks or impacts. Incorrect handling will cause the lifespan of the bearings to be reduced or the bearing to be damaged.
The axial forces (Fa) permitted during the installation of pinion gears, couplings, etc. depend on the motor size and can be found in the following table:
- Size of motorPermitted axial force Fa [N]Standard bearing14802100031650
The radial force (Fr) on the shaft end is made up of the installation forces (e.g. belt tension on pulleys) and operational forces (e.g. load torque on the pinion). The maximum radial force (Fr) depends on the shaft end type, bearing type, average speed, position where the radial force is applied and the desired lifespan of the bearings.
Axial force, shift in shaft position caused by axial force
The axial force (Fa) on the shaft end is made up of the installation forces (e.g. stress caused by installation) and operational forces (e.g. thrust caused by slanted tooth pinions). The maximum axial force (Fa) depends on the bearing type and the desired lifespan of the bearings. The fixed bearing is secured on the A flange (with size 1 the fixed bearing is on the B side flange and the floating bearing is on the A side flange) with a retaining ring. The floating bearing is preloaded on the B flange with a spring in the direction of the A flange. Axial forces in the direction of the B flange can cause the spring bias to be overcome and the shaft is shifted by the amount of axial play in the bearing (approx. 0.1 - 0.2 mm). This shift can cause problems on motors with holding brakes or motors with EnDat encoders. Therefore, no axial force is permitted in the direction of the B flange when using these motors.
The shaft ends of motors with holding brakes are not permitted to have axial loads applied. Especially axial forces in the direction of the B flange should be prevented because these forces can cause the brake to fail.
Determining permissible values for Fr and Fa
Information to determine permissible values of Fr und Fa can be taken from the motor data for the respective servo motors. Permissible values are based on a bearing lifespan of 20000 hours (bearing lifespan calculation based on DIN ISO 281).