BECKHOFF AL2000 Application - Manual (Page 30)

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Step 4: Motor sizing
Two main criteria for the motor’s thrust force should be kept in mind:
1. A linear motor’s peak force is depending on the velocity of the coil unit. This can be seen in the linear motor
Specification Diagrams.
Peak force versus velocity (velocity and force in the same direction)
As shown in the diagram this effect depends on the power supply. The speed at F=0 is the limit. For more dia-
grams see the appendix - ’Peak force - velocity diagrams’.
2. F
rms
must remain below the motor’s specified continous force Fcont. The continuous force is a measure for
the thermal load of the linear motor. Amongst others it depends on the cooling conditions. For watercooling,
Fcont is specified. Without cooling, F
cont
is to be estimated. For more information, see the appendix ’Heat trans-
fer and Temperature’.
Choose a linear motor which meets both criteria.
From the calculated mean force and the specified motorconstant the dissipated power is obtained.
This power equals the heat production in the coil unit. It has to be conducted to ambient.