ACT (RS) ABB Loco (English) (12. AUXILIARY POWER CIRCUIT)

January 10, 2021, 12:02 PM

Auxiliary Converter

General:-

The motors used for the auxiliary circuits are 3-phase squirrel cage motors. The cost of maintenance is therefore low. There are total 12 auxiliaries run by 3-phase, 415 V AC supply. This 3- phase 415 V, AC supply is obtained by Auxiliary converter to feed different 3-phase auxiliaries and one battery charger.

The auxiliary circuits are controlled as required. The traction motor and oil cooling blowers run only when required. The control electronics adjusts the blower speeds depending on measured operating temperatures, nominal traction values and speed.

Transformer and traction converter oil pumps work continuously whenever the auxiliary converters are operating.

Auxiliary converter receives single-phase AC 1000 volts supply from auxiliary winding of main transformer.

This single-phase supply is fed to rectifier module auxiliary converter where it converts into DC supply. This DC supply is fed to DC link to suppressed AC pulses in DC.

The pure DC supply then fed to inverter module auxiliary converter where it converts DC supply to 415V, 3-phase AC supply with variable amplitude of voltage and frequency and then fed to different 3-phase auxiliaries.

There are three, auxiliary converters which get single phase 1000 volts AC input supply from common auxiliary winding and fed 3-phase 415 volt out put to different 12 auxiliaries and one battery charger.

Auxiliary converter-1 is placed in cubicle called BUR-1 situated in machine room no-1 where as aux converter no. 2 and 3 are placed in cubicle BUR-2, which is situated in machine room no. 2

Auxiliary Power Circuit-

3-phase, 415 volt Auxiliaries

Following 3-phases, 415-volt auxiliaries are provided on this loco, which are fed from Auxiliary converter no. 1, 2 and 3.

Load Sharing

Generally all the 3 Auxiliary converters are loaded equally, but in case of failure of any converter another converter shares its load. In such condition, frequency of aux. Motor drops from 50 Hz to 37Hz.

Load sharing after isolation of any aux. converter.

Note: –

1.Machine Room blower and scavenging blowers (2+2) are directly supplied and starts as soon as VCB is closed independent of MCE in driving as well as in cooling mode.

2.The oil pump for transformer and converter works continuously during operation of converter.

3.TM blower and, oil cooling blower and scavenging are run as per requirement. The control electronics adjust the selected stage of measured operating temperature; nominal traction value and speed range lower – moderate – maximum. However, RDSO has issued instructions for the removal of 24 Hz from BUR1 to minimize OCB failure.

Main Compressor 1 & 2

Starting:

For starting the main compressor a spring-loaded switch (BLCP) is provided on panel, ‘A’ which is having 3 positions.

1.‘OFF’ position – For stopping compressors.

2.‘AUTO’Position -Compressor 1&2 will work alternately according to cut in and cut out of cycle.

3.‘MAN’Position -Compressors work continuously irrespective of MR pressure. This is spring-loaded position.

Auto Position

1. Air pressure goes below 8 kg/cm2 Only one compressor start alternately up 10 kg/cm2 .

2. Air pressure goes below 6.4 Kg/Cm².Both compressors start till pressure reaches to 10 kg/cm2

3. Air pressure goes below 5.6 kg/cm²: “Low pressure, main reservoir” message appears on the screen with priority-1 fault along with LSFI indication. No TE/BE is possible till MR pressure reaches to 6.4 kg/cm2 . Both compressors will start till MR pressure reaches to 10 kg/cm2 .

4. After getting the start command, compressor starts but it takes 25 seconds to ramp up and unloading and start actual pumping there after. During this delay, pressure drops by 1 to 1.5 kg/cm2 . So if we sees the gauge cut in cut out setting will be appear as 7 to 10 kg/cm2 instead of 8 to 10 kg/cm2 .

SINGLE-PHASE 415 V/110 V AUX.CIRCUIT:-

The auxiliary transformer is located in cubicle-1(HB-1) and supplies following systems with 1-phase power. This circuit is independent of CE and all these auxiliaries work in Driving as well as cooling mode and start as soon as VCB closed.