Posted 03 September 2023 - 10:59 AM
There are two main electrical circuits in these types of locomotives. HV (high voltage) circuits, i.e. those that are supplied with the voltage from the traction network, and LV (low voltage) circuits, i.e. those that are supplied with 110V DC on-board voltage. The on-board voltage is generated by the main converters supplied with voltage from the HV circuit, and in the absence of HV power supply or the converters are turned off, the LV circuits are powered by the accumulator battery, which is charged by them during normal operation of the converters.
The HV circuits include:
- HV main circuit, i.e. power supply circuit for traction motors,
- HV auxiliary circuits, which are divided into:
- circuits of main converters,
- driver's cab heating circuit
- trainset heating circuit
The LV circuits include:
- LV auxiliary circuits, which are supplied from the main converters, are divided into:
- converter circuits
- main compressor motor circuits,
- control circuits of motors of starting resistance fans,
- battery circuit,
- auxiliary compressor motor circuit,
- train heating circuit,
- driver's cab heating circuit,
- cabin stove circuit,
- high-speed switch control circuit,
- desktop ammeter circuits,
- signaling circuits,
- lighting circuits.
Rotating converters with traction motor fans:
In the EU06 and EU07 electric locomotives, two rotating converters of the MG 91H type are installed in the machinery space. These are electric machines used to convert the mains voltage into 110V on-board voltage, which is used to charge the batteries and power low-voltage on-board devices. The converter consists of a separately excited DC motor powered by a 3kV mains voltage and a separately excited generator generating 110V electricity, built on one shaft and a common body. A fan is installed on the shaft on the motor side to ventilate the described electric machine. On the generator side, the converter is integrated with the fan blower of the traction motors.
Basic data of the converter:
- engine continuous power: 30.9 kW,
- motor rated voltage: 3000 V,
- motor rated current: 12.7 A,
- generator continuous power: 17 kW,
- rated current of the generator: 155 A,
- nominal spin speed: 1310 rpm,
- fan capacity of traction motors: 204 m3/min,
- weight without fan and cover: 1660 kW,
Rotating converters with traction motor fans:
The motors of the converters are supplied from the HV circuit behind the fast circuit breaker. The circuit of the converters includes the converters' contactors, the converter's excess relay mentioned earlier, the protective resistor, the protective transformer, the starting resistor, the externally excited HV winding and the auxiliary undervoltage - current relay.
The contactors of the converters are installed in the HV 1 compartment and are used to switch on and start the converter motors. The SMA 25 contactor acts as the switching contactor, while the SMB 25 contactor is responsible for starting the converter motor. The contactors in question are made of an electromagnet drive of the main contacts and an extinguishing chamber. SMA-25 contactors are additionally equipped with auxiliary switches. The drive consists of: the electromagnet core with the excitation coil and the armature.
The SMB 25 start-up contactors are controlled by the PVJ-25 start-up relays of the converters.
The protective resistor is used to limit the short-circuit currents of the motor, reduces the starting current and mitigates the voltage changes occurring in the traction network.
The protective transformer protects the motor operation in a transient state and plays an important role in the case of large voltage drops in the catenary.
The starting resistor is used to limit the starting current. Works with contactor SRP1 and relay PRP1. When the starting current of the motor is less than or equal to 20A, the PRP1 relay closes the circuit of the starting contactor coil of the converter. This contactor, on the other hand, closes its contacts causing the starting resistor to be disconnected from the circuit.
The PPZ1 undervoltage and voltage relay protects the motor against the effects of current return after its sudden decay. Opens the starting contactor circuit and activates the starting resistance when the motor is restarted.
The excitation circuits of the converters include a non-contact voltage regulator type IRM-1/110V, which is used to stabilize the 110V voltage produced by the converter. The task of the regulator is to maintain a theoretically constant voltage value (106.5-113.5V) regardless of its rotation. Each of the converters has an independent regulator.
The timing circuits of the converters are protected with 5A automatic circuit breakers, which are located in the driver's assistant desks. The converter is switched on by the driver by switching the toggle switch on the panel.
When the converters are turned off, the power supply to the on-board network elements is provided by the accumulator battery. The battery unit is housed in two boxes, in the space between the bogies under the frame. The 4G60H type nickel-cadmium battery consists of 72 series-connected cells placed in 24 boxes, giving a total output voltage of 96V DC. The battery is charged by one of the working converters. A diode is included in the battery circuit, which acts as a reverse current relay and disconnects the battery power supply when the voltage from the generator is lower than the current battery voltage. The battery is protected by 2 Bi-Wts 60A fuses and by a 63A automatic circuit breaker, which also serves as a battery disconnector, which is located on the automatic circuit breaker panel in the driver's desk - cabin A. This disconnector turns off the battery power supply, cutting it off from the LV circuits for the duration of parking when the locomotive is idle.