RAIL EMPLOYEE'S INFO: WDG-3A - सेफ्टी डिवाइस ( Safety Devices )

1/03/2021

WDG-3A - सेफ्टी डिवाइस ( Safety Devices )

Safety Devices

Safety devices are provided for the safety of the engine & loco. They are

1. Over Speed Trip Assembly (OSTA) - It is located on engine right side free end. It protects the engine from over speeding. On 8th notch the engine rpm is 1050. Due to any reason engine speed exceeds up to 1180 ± 20 rpm, OSTA will operate, fuel rack comes to zero and engine will shut down without any indication. Two handles are provided on OSTA, small is trip handle and big is reset handle. To reset OSTA, pull reset handle gently.

Note -

1. If OSTA trips during transition, reduce one notch.

2. If OSTA trips on higher notches, work on lower notches.

3. If OSTA trips repeatedly, check the wire connections of Techo. generator and inform the power controller. 4. Ensure that OSTA is reset before starting the engine and press the governor linkage.

2. Oil Pressure Switch (OPS) - In EH governor it is located in loco pilot cab on nose compartment wall, whereas in WW governor loco, it is inside the governor. It protect engine from low lube oil pressure. In EH governor loco OPS pick up at 1.6 kg/cm² and drop at 1.3 kg/cm². When oil pressure drops to 1.3 kg/cm², OPS operate and engine will shut down with following indication -

1. Low lube oil lamp will glow on both control stands.

2. Alarm bell will ring.

3. In WW governor shut down plunger will came out. In WW governor OPS pick up at 1.3 kg/cm² and drop on 1.1 kg/cm². Engine will not crank till shut down plunger reset properly.

3. Low Water Switch (LWS) - It is located in Expresser room below expansion tank no.1. It protects the engine from low water. Each expansion tank capacity 155 liters and its level is 14 inch. Whenever water level remain 1 inch LWS will operate, engine will shut down with following indication

1. Alarm bell will ring.

2. Hot engine lamp will glow on both control stands.

Note - If LWS defective, check the water level, if it is sufficient then short the wire 50D - 5OJ in EH governor and 16E - 16H in WW governor and inform the power controller.

4. Circuit Breaker (CB) – Circuit breaker is located on the front panel and on both control stands. It protects the electrical circuit from over current. It has three positions ON, OFF and Trip. In OFF condition the knob of the circuit breaker will be in down position, in ON condition the knob will be in upper position and during TRIP the knob will be in the Centre. To reset the circuit breaker first kept in OFF then in ON position.

WDG-3A is equipped with following circuit breaker –

1. MB1 Main Battery breaker (200A)

2. MB2 Main Control Breaker (150A)

3 MFPB1 Master Fuel Pump Breaker No.1 (30A)

4. MFPB2 Master Fuel Pump Breaker No.2 (30A).

5. CEB Crank Case Exhauster Breaker (15A)

6. FPB Fuel pump Breaker (30A)

7. MCB1 Master Control Breaker No.1 (15A)

8. MCB 2 Master Control Breaker No.2 (15A)

9. AGFB Auxiliary Generator Field Breaker (15A)

10. RFCB Radiator Fan Circuit Breaker (30A)

11. Cab Light circuit Breaker (15A)

12. Dome Light Circuit Breaker (30A)

13. Head Light Circuit Breaker (30A)

14. DEB Dust exhauster blower Breaker (15A)

15. Air Dryer Breaker (15A).

5. Safety Auxiliary Relay (SAR) - It is located in front panel of EH Gov. Loco. It protects the auxiliaries from over speeding. The SAR coil is connected in series with governor speed coil. If the governor speed coil supply is interrupted due to any reason the engine speed will suddenly increase, it is protected by SAR coil. When the supply to speed coil is interrupted, SAR will de-energize and it’s NCI 50K-50D on governor clutch coil branch will open. Due to this, clutch coil de-energize and engine will shut down without indication.

6. Ground Relay (GR1) - It is located on front panel. It protects the power circuit from grounding. Its coil is connected to main generator armature circuit and loco body. In case of grounding in the power circuit GR1 will energize, Due to this following changes are take place.

a) Engine speed comes to idle.

b) GFC will drop.

And following indications

a) GR lamp glows on both control stands.

b) Alarm bell rings.

c) GR1 knob comes out.

d) GR1 pointer will go on red point.

e) Load meter will show zero.

Before resetting GR1, check power circuit, keep MH and ECS on Idle, and then press the reset knob.

Note- In WDG3A loco two GR are provided, GR1 for power circuit and GR2 for starting circuit. When GR2 operates it is called starting ground and when GR1 operates it is called power ground.

7. Dead Men’s Relay/ Pneumatic Control Switch (DMR/PCS) - DMR is located on front panel and PCS1&2 in nose compartment

• When due to any reason HB5 valve operates, PCS1 will also operate; its NCI will open on the branch of DMR coil.

• When due to any reason BP pressure drops up to 0.6kg/cm2, PR3 operates; its NCI will open on the branch of DMR coil.

• When loco pilot apply A9 in emergency or BP pressure drops up to 2.2kg/cm2 PCS2 operates, , its NCI will open on the branch of DMR coil DMR de-energize with following indication

a) Electric brake warning (PCS) lamp glows on both control stands.

b) Engine speed comes to idle.

c) TM will get Ist notch current even if TH is on notches.

d) Dynamic brakes will cut off automatically, if applied.

8. Generator Field Over Load Relay (GFOLR) - It is provided only in alternator loco on front panel. It protects the field winding of the alternator from over current. When over current flows in field winding of alternator. GFOLR will energize with following indications

a) Engine speed comes to idle.

b) GFC will drops & Load meter shows zero.

c) Alarm bell rings.

d) Over Load lamp glows on front panel. To reset GFOLR, bring MH On idle and press push button on front panel. Do not reset it more than 2 times. If again it trips then declare the loco failed and inform the power controller. Note - Setting of GFOLR is 280 ± 5 amps

9. Vent Air Pressure Relay (VAPR) - It is provided only in alternator Loco on front panel. It protect rectifier block from insufficient air supply. Air given by PDR motor. If PDR motor fails, VAPR will energize with following indicationa) Alarm bell rings.

b) Vent air flow (Rectifier) lamp will glow on front panel.

c) Engine speed comes to Idle.

d) GFC will drop. Check PDR wire connection and its circuit breaker, inform PCOR. To reset VAPR keep throttle handle and ECS on idle.

10. Wheel Slip Relay (WSR) - It is provided on front panel above power contactors. It protect rail and traction motors from slipping. When current difference between two respected traction motor is more than prescribed limit, then WSR energized with following indications -

a. Buzzer sounds.

b. Wheel slip indication lamp glows on both control stands.

c. Load meter needle fluctuates.

d. Auto sanding takes places under the wheels. Each WSR has two coils, connected in SP and P combination as under –

11. Engine Temperature Switch No. 3 (ETS-3) - It is located on engine right side in expresser room. It gives indication of hot engine alarm. When water temperature rises to 94oC, ETS-3

pick up with following indications –

a. Hot engine lamp will glow on both control stands. b. Bell ringing. In such condition, if load and road permitted, reduce the notch up to 2-3, switch off GFCO and raise the engine. When temperature reduced to 91oC, ETS-3 will drop. Work the train as normal procedure. Safety Fittings

1. Head light (with proper focus)

2. Flasher light

3. Marker light (with red glass)

4. Rail Guard

5. Cattle Guard

6. Foundation bolts of Buffer.

7. CBC locking pin

8. Horns

9. Wipers 10. Sanders (with pipe fitment)

11. Speedometer (with speed recorder)

12. Equalizing beam (Equalizer) and beam plate bolts.

13. Brake blocks hanger pins and its retaining bolts.