3 Engineering | LXM32 |
Use only resistors that are specified as braking resistors. See chapter "2.3 Braking resistor", page 17 for suitable braking resistors.
Connection of braking resistor Braking resistors with degree of protection IP65 may be installed out- side the control cabinet in an appropriate environment in order to decrease the temperature in the control cabinet.
The external braking resistors listed in the Accessories chapter are shipped with an information sheet that provides details on installation.
Further procedure:
•Connect the braking resistors to the drive.
•LXM32: Check the parameter RESint_ext during commissioning. This parameter allows you to switch between internal and external braking resistor.
•LXM32: If you have connected an external braking resistor to an LXM32 drive, you must set the parameters for the external braking resistor during commissioning.
•During commissioning, test the braking resistors under realistic conditions, see page 54.
Wire ferrules: If you use wire ferrules, use only wire ferrules with col- lars for these terminals.
3.5.2Rating information
To rate the braking resistor, calculate the proportion contributing to absorbing braking energy.
An external braking resistor is required if the kinetic energy that must be absorbed exceeds the total of the internal proportions, including the internal braking resistor.
The energy Evar is the square difference between the voltage before the deceleration process and the response threshold.
The voltage prior to the deceleration process depends on the mains voltage. The energy absorption by the DC bus capacitors is lowest when the mains voltage is highest. In the calculation, use the values for the highest mains voltage.
Energy absorption braking resistor Two characteristic values determine the energy absorption of the braking resistor:
•The continuous power PPR is the amount of energy that can be continuously absorbed without overloading the braking resistor.
•The maximum energy ECR limits the maximum
If the continuous power was exceeded for a specific time, the braking resistor must remain without load for a corresponding period.
The characteristic values PPR and ECR of the internal braking resistor can be found in chapter "2 Technical Data".
See page 22 for information on assessing the electrical and mechani- cal losses.
Example: LXM32 drive Deceleration of a rotary motor with the following data:
MNA01M001EN, V1.01, 08.2014
34 | Common DC bus |
