Technical data

• DOK-DIAX02-DDC01******-PRJ1-EN-E1,44 • 01.97

3. Electrical Connections - Installation Guidelines

3.12. Control Circuit of the DDC Mains Contactor

The general operating method as suggested by INDRAMAT is to control the

mains contactor and dynamic braking in the DDC. Selection of the control

method and its effects will depend on the functions offered and the responses

of the entire system. It is, therefore, the responsibility of the machine builder.

With dynamic braking, synchronous motors are always braked to a standstill

(MAC or MDD) whether electronic circuitry in the drive is still operational or not.

The dynamic brake functions as an additional protective device for the

machine.

Inductance motors (2AD or 1MB) are not braked when the DC bus is short-

circuited.

Without dynamic braking, properly functioning drives can be braked at

maximum torque. However, if there is trouble in the closed-loop electronic

control system or if there is a discontinuity in the feedback line, it should be

expected that drives will coast without electrical braking. Dynamic braking can

only be eliminated when non-braked deceleration does not damage the

system. As an alternative, motors equipped with mechanical holding brakes

can be used.

How to stop the drive in the event of a fault will depend on the

functions offered on the system. In the final analysis, this decision

can only be reached by the system designer. Thus, the following

recommended is intended only as a guide to the system designer.

Standstill with fault in

drive electronics with/

without DC bus

dynamic braking