Siemens SINAMICS PERFECT HARMONY GH180 - 4.1.4 Cell Section

Depending upon order speci󹪝cations, the transformer is con󹪝gured for 18 or 54-pulse for 9-cell
systems, 30-pulse for 15-cell systems, and 42/48-pulse for 21/24-cell systems power quality by
using extended delta 750 V or 450 V secondary windings.
The transformer is a dry type forced air-cooled unit, and polyglass air ba󹪠es are used to direct
air movement across the coils. All SINAMICS Perfect Harmony™ GH180 transformers are
thermally monitored.
All connections to and from the transformer are made with insulated wire. The transformer is
equipped with o󹪜-line taps to accommodate utility line variations, +5%, 0%, and -5% are
supplied on typical units (at shipment, the units are placed on the 0% tap).
Dependent upon order speci󹪝cations, the winding conductor material may be aluminum or
copper.
The transformers are appropriately sized for the application. However, other factors such as
motor lead-length, motor service factor, environment conditions, ambient conditions, altitude,
and power cell redundancy must be considered.
4.1.4 Cell Section
The basic electrical diagrams for all SINAMICS Perfect Harmony™ systems are similar. One of the
most critical components of the drives is the power cell. The cell voltage is 750 V or 450 V
depending upon the drive output voltage. Depending on the operating load voltage, the
quantity of cells used to develop the multi-level PWM output waveform varies.
Each power cell input side is con󹪝gured as a 6-pulse diode recti󹪝er. Terminals are supplied with
power via a secondary winding of the transformer. The DC output of the recti󹪝er is 󹪝ltered via the
capacitor bank and supplies power to a single-phase inverter on the output side. Output
terminals of each cell are connected in series in each phase group.
Note
Discharging the DC Link
The power cells include discharge resistors to dissipate stored energy after the input voltage is
removed. The power cell DC bus voltage decays to less than 50 VDC in less than 10 minutes.
Fuses
The secondary of the transformer is routinely fused. The fuses are mounted externally on the
front panel of the power cells (located in the cell section). Only two phases of each transformer
secondary (power cell input) are fused. Each fuse has a visual blown fuse indicator, making it
easy to diagnose a fuse’s condition. Fuses are forced air-cooled for longer life and less thermal
stress.
Note
Permitted Mixture of Fuse Vendors
A mixture of fuse vendors is permitted, but not within the same power cell.
Description
4.1 Cabinet Details
Type 6SR5 Air-Cooled
20 Operating Instructions, AK, A5E39390112