RS - RX
The following formula provides a good approximation to the radial force of the pulley :
M
=
×
Fr
K
10
R
The belt tension must never exceed the values specified by the manufacturer. Tension can be
determined with a device for measuring the natural belt frequency in deflection.
If a gearbox is to be used, installation of our standard gearboxes in the factory is recommended.
Check that the gearbox stresses are suitable for the motor, in particular the no-load friction torque.
In the specific case of direct coupling, the gearbox must provide isolation.
Installation of a servomotor with an encoder kit
if the encoder is mounted directly on the end of the drive shaft :
As far as possible, avoid axial forces on the shaft. They should always be lower than the values given
in the catalogue.
•
Prevent impact on the encoder.
•
Avoid difficult ambient conditions (high vibration, pollutlon, etc.).
•
The maximum operatinq temperature in the encoder is 70°C.
•
Ask for our individual encoder files.
2.5 Electrical connection
•
Check the continuity of the earth circuit is via the machine casing.
•
Use wires of sufficient cross-section to prevent voltage drops. Looking from the end of the drive
shaft, the servomotor rotates in a clockwise direction if the + motor wire is connected to the
positive terminal.
•
If the motor races reverse the tachometer wires
•
If it rotates in the wrong direction : reverse the tachometer and motor wires.
•
Electrical protection must be provided to prevent too high a current which would cause abnormal
wear of the servomotor. In general, these servomotors are supplied by an electronic assembly
which gives a ripple current.
•
If the effective current/average current ratio (or form factor) is high, this ratio should be brought
down to a value close to 1 by adding a smoothing self-induction coil of appropriate value in series
with the servomotor.
Fr = radial force (N)
M = maximum torque during use (Nm)
3
R = pulley radius (mm)
K = 1.5 with a timing belt
K = 2.5 with a V belt
K = 3.5 with a flat belt
PVD 3405 01/2003
10