Description; Applicability; Principle Of Operation - Siemens SIMOVERT Master Drives Betriebsanleitung

02.04
1

Description

1.1

Applicability

The common rectifier in the SIMOVERT Master Drives series is a power electronics device. From the three-
phase mains, it generates a dc network and is used as a dc supply unit for one or several units in the
SIMOVERT Master Drives inverter series with a dc link.
A three-phase mains is connected to the input. One or more inverters and a brake chopper can be
connected to the DC output. The total of the rated currents of the installed inverters may then exceed the
rated current of the common rectifier. It must however be ensured in the course of system planning that at no
moment in time is the total of DC load currents greater than the rated DC current of the common rectifier.
Feedback to the mains is not possible.
The double rectifiers are specially designed for constructing an 18-pulse rectifier unit. The unit is constructed
on the basis of the plant builder's application know-how.
Refer to the technical data in Chapter 14 for details of voltage and current ranges.
1.2

Principle of operation

The common rectifier consists of a 6-pulse thyristor bridge for controlled rectification of the three-phase
mains. The trigger equipment is independent of the rotary field and is frequency-compensated from 46 to 64
Hz. After the electronic power supply and the mains voltage have been applied, the dc link is precharged by
shifting of the phase control firing angle within one second (adjustable to two seconds).
The maximum DC link capacitance of a group drive must not exceed three times the capacitance of a single
inverter whose DC link rated current corresponds to the rated current of the incoming unit. Units for
operation with higher DC link capacitance on request.
If the DC link voltage drops below a given proportion of the average mains voltage as the result of mains
power failure or a drop in the mains voltage, the pulses are blocked immediately and precharging takes
place again as soon as the mains returns. This prevents excess currents as the result of charging of the dc
link capacitors at too fast a rate when the mains voltage returns.
Tapping of load current is not possible during precharging.
An earth fault of a connected converter is checked before precharging to protect its frewheeling diodes
against excess current.
The mains voltage, phase failure, excess temperature of the power section, earth faults and the electronic
power supply are monitored. Monitoring triggers deactivation and a fault signal in the event of any hazard.
The current is not monitored.
Fault signals are acknowledged by deactivating the mains voltage or the electronic power supply.
The power for the electronics is supplied externally via a 24 V DC input.
In contrast to standard rectifier units, double rectifiers consist of two uncontrolled 6-pulse diode bridges. The
two diode bridges integrated in the device have no DC link precharging; this must instead be implemented
via the application.
Both rectifiers can be operated simultaneously with the rated data. The device contains no electronic or
monitoring circuits whatsoever and therefore requires no external 24 V power supply. The fan is not switched
by internal relays.
The built-in temperature sensor is brought out at terminals and can be externally evaluated.
Siemens AG 6SE7087-6AE85-0AA0
Common Rectifier Operating instructions
Description
1-1
ENGLISH