Modular Systems

The ATS modular rack system provides a clean, efficient propulsion solution for new or refurbished locomotives & marine vessels

Included in the locker or rack is the Rectifier, DC Capacitor Bank(s), Traction Module(s), Dynamic Brake Controller, Auxiliary Supply, Cooling Manifolds and Control Wire Harness assembly.


  • Over 30 locomotive systems in daily operation
  • Modular rack construction
  • Automatic wheel-slip and wheel-slide control
  • Automatic regenerative braking to near zero speed
  • EN45545 Compliant
  • Common power module for armature, field and brake choppers

Potential System Power Electronics:

Rectifier Module

750kW Module

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.

  • AC Input Voltage: 730 V & 800 V versions available
  • Peak Current: 1,500 & 2,000* A versions available
  • Continuous Current: 1,200 & 1,500* A available
  • EN45545 Compliant

* available in 800 V version

DC Link Capacitor

Capacitor Bank

Designed to handle transients and stabilize the DC bus

  • DC Voltage: 800 & 1000 V versions available 
  • Capacitance: 3,120*, 4,800, 5,000, & 10,400 µF versions available
  • Stainless-Steel construction

* available in 1000 V version

Brake Chopper Module

750kW Module

Controls excessive voltage caused by dynamic braking by dumping energy into power resistor(s)

  • DC Bus Voltage: 750V
  • Rated Current: 1500A
  • Power at Rated Voltage: 1430 kW
  • EN45545 Compliant


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.

Field & Armature Chopper Module

750kW Module

Controls Field or Armature of DC Motors

  • DC Bus Voltage: 750V & 1000V versions available
  • Rated Current: 1000A & 700A versions available
  • Power at Rated Voltage: 600 kW & 635 kW versions available
  • EN45545 Compliant


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.

Locomotive Traction & Marine Propulsion Inverter Module

750kW Module

The Locomotive Traction & Marine Propulsion Inverter Module is used in AC induction motor applications:

  • DC Bus Voltage: 750 & 1200V versions available
  • Peak Current: 800 A
  • Power @ Nom. Voltage: 475 & 750 kW versions available
  • Max Frequency: 200 Hz
  • EN45545 Compliant
  • Adaptive Torque Control

Dual Inverter Module

Dual Power Module

The Dual Inverter Module can be configured to supply power to two of the following:

  • Pumps
  • Fans
  • Compressors
  • Auxiliary Supplies
  • Thrusters (Marine)

Dual Chopper Module

Dual Power Module

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.

  • DC Bus Voltage: 750V
  • Rated Current: 500A

Solar Cell DC/DC Chopper Module

Dual Power Module

Controls energy captured from solar cells

  • DC Bus Voltage: 750V
  • Rated Current: 500A
  • Power at Rated Voltage: 350 kW
  • EN45545 Compliant