3 PHASE LOCO में लगे सभी सेफ्टी और अर्थ फॉल्ट रिले | Working of All Relay in 3 Phase Locomoitive

Summary

The video explains the location and function of the main overcurrent, voltage-protection, and earth-fault relays used in a three-phase locomotive. The presenter refers to circuit diagrams and notes to show what each relay monitors, what happens when it operates, and how its signal reaches the locomotive’s control electronics and DDS display.

1. OCR 78 — Overcurrent relay

• Location: SV panel.
• Function: Monitors current and causes the circuit breaker to open when current exceeds the applicable limit.
• The presenter describes a normal-operation threshold of about 360 A. During initial breaker closing, a temporary inrush-current allowance is provided for roughly one second; the subtitles’ exact current figures for this interval are garbled.
• A timing relay and resistance in the circuit help manage the initial transformer inrush current.
• When OCR 78 operates, it interrupts the breaker’s closing/holding circuit and reports a priority-one overcurrent fault, identified in the subtitles as F0108 P1.
• The relay has a target/lockout feature. Before resetting it, the presenter advises checking for signs of a genuine fault—such as abnormal transformer or SR oil, smoke, or fire—and then resetting the target by turning it clockwise.

2. MVR 86 — Minimum/maximum voltage relay

• Location: SV panel.
• Function: Detects supply voltage outside the stated range of approximately 17.5–30 kV and can open the VCB, producing a priority-one voltage fault identified as F0104 P1.
• Its role is particularly relevant in cooling mode: if the relay or its energizing circuit is faulty, the breaker may not close or hold as required.
• The presenter says that, in driving mode, voltage monitoring is handled through the SRV’s processors, so MVR 86’s operation has less direct effect on driving.
• The presenter notes that cooling mode has been deactivated in some locomotives and that the relay has been removed in some cases.

3. Earth-fault relays

When an earth fault is detected, the relevant relay picks up and sends a signal to the central electronic system, which displays a fault on the DDS. The presenter says that normal operation can generally continue for the earth-fault conditions discussed, though the fault indication remains.

Relay Circuit monitored and location described Signal/message details given 89.2 Auxiliary three-phase AC power circuit; location is not clearly stated in the subtitles. Sends an earth-fault indication to the central electronics/DDS, described as priority 2. The subtitles give contact numbers as 2801B–2858. 89.5 415 V and 110 V circuit; HV panel. Sends a priority-two earth-fault indication. Contact numbers are rendered as 280A–2859 in the subtitles. 89.7 Control/battery-charger circuit; SBV panel. DDS indication described as F0905 P2. Contact numbers: 2801–2870. 89.6 Harmonic-filter circuit; harmonic-filter cubicle. DDS indication described as F0402 P2. Contact numbers: 2801–2689. 38.1 Hotel-load circuit; inside the hotel-load converter. Sends a priority-two earth-fault indication. The subtitles give the contact numbers as 280–2860. 89.4/1 and 89.4/2 DC links associated with SR1 and SR2, respectively; located inside the corresponding SR equipment. The presenter describes these links as charged to about 2800 V. These relays provide earth-fault indications for the respective DC links; the exact message codes are unclear in the subtitles.

4. Processor monitoring mentioned

• 89.2: Monitored through the STB2 processor.
• 89.5, 89.6, and 89.7: Described as monitored through the HBB and Control Electronic 1 (Cell 1 / 411).
• The subtitles do not clearly identify the processor monitoring 38.1 or 89.4/1 and 89.4/2.

Note: Several relay names, thresholds, contact numbers, and message codes are unclear or distorted in the auto-generated subtitles, so the figures above are presented as stated where reasonably legible.

Speakers and sources

• Speaker: One narrator/instructor, explaining the relay functions and circuit diagrams. No other speakers are identified.
• Sources/materials featured: The presenter’s notes and circuit diagrams. The video is from Loco Study By Raju Kumar.