The Rectifier Module converts the AC voltage from a generator to DC voltage for inverters and choppers
The Rectifier Module converts 480V, 60Hz AC power to DC power at a voltage of approximately 650V. The Rectifier Module consists of a half-controlled SCR / Diode bridge for the purpose of limiting the charging current drawn by the bus capacitors during power up.
* available in 800 V version
Designed to handle transients and stabilize the DC bus
* available in 1000 V version
Controls excessive voltage caused by dynamic braking by dumping energy into power resistor(s)
Energy recovered from the traction motors during dynamic braking is returned to the DC bus. All of the energy returned to the bus must be dissipated without resulting in a large increase in voltage. The excess power is absorbed in dynamic brake resistors controlled by the Dynamic Brake Chopper. The Dynamic Brake Chopper normally operates independently by responding only to the increase in DC bus voltage that occurs when power absorbed by the Armature Chopper Modules is returned to the DC bus.
Controls Field or Armature of DC Motors
When the Armature Chopper Module is used to control the armature of a DC traction motor, it controls the armature current by applying pulses of the DC bus voltage directly to the armature at a frequency of 1 kHz. The chopper can supply the armature with a very large amount of current at low speed while consuming a relatively small amount of current from the DC bus. The Armature Chopper Module also receives speed feedback from the axle encoder that it is driving and continuously compares the measured axle speed with a reference encoder input derived from a non-driven axle. For the purpose of controlling wheel-spin or wheel-slide, a speed regulator overrides the traction reference with a lower value if the axle speed deviates outside a small band of acceptable values.
The Armature Chopper Module can also operate very effectively as a brake down to very low speeds. It achieves this by applying a voltage to the armature that is lower than its open-circuit voltage so that both current and power flow are reversed. This change occurs as a seamless transition when the polarity of the traction reference is reversed.
The Locomotive Traction & Marine Propulsion Inverter Module is used in AC induction motor applications:
The Dual Inverter Module can be configured to supply power to two of the following:
When a small enough motor is used for a traction or propulsion application, the Dual Chopper Module can be configured as a dual Field Chopper, dual Armature Chopper, or a Field Chopper and Armature Chopper.
Controls energy captured from solar cells