A Detailed presentation on RELAYS in Conventional Locomotives.

A Detailed presentation on RELAYS in Conventional Locomotives.
Relay has multiple meanings:
Electrical device
An electrically operated switch that can be used for remote or automatic control. It has input terminals for control signals and operating contact terminals. When there's a change in an electrical circuit, the relay moves switches or other devices in the circuit. Relays are used to protect electrical systems from high voltage or current, and to safely operate connected equipment. They can be found in many applications, including commercial, industrial, home, and consumer products.
A relay is an electrically operated switch. It consists of a set of input terminals for a single or multiple control signals, and a set of operating contact terminals. The switch may have any number of contacts in multiple contact forms, such as make contacts, break contacts, or combinations thereof. Relays are used where it is necessary to control a circuit by an independent low-power signal, or where several circuits must be controlled by one signal. Relays were first used in long-distance telegraph circuits as signal repeaters: they refresh the signal coming in from one circuit by transmitting it on another circuit. Relays were used extensively in telephone exchanges and early computers to perform logical operations.

The traditional electromechanical form of a relay uses an electromagnet to close or open the contacts, but relays using other operating principles have also been invented, such as in solid-state relays which use semiconductor properties for control without relying on moving parts. Relays with calibrated operating characteristics and sometimes multiple operating coils are used to protect electrical circuits from overload or faults; in modern electric power systems these functions are performed by digital instruments still called protective relays or safety relays.

Latching relays require only a single pulse of control power to operate the switch persistently. Another pulse applied to a second set of control terminals, or a pulse with opposite polarity, resets the switch, while repeated pulses of the same kind have no effects. Magnetic latching relays are useful in applications when interrupted power should not affect the circuits that the relay is controlling.

1. RELAYS

2. RELAY MEANS IT IS A SENSITIVE DEVICE. IT CHECKS THE PROPER FUNCTIONING OF THE OPERATORS. IN CASE OF ANY ABNORMALITY IN APPARATUS GIVES INDICATION TO LOCO PILOT. IT IS NORMALLY REPRESENTED BY ‘Q’.

3. CURRENT RELAY: CURRENT RELAYS ARE DEVIDED IN TO 2 TYPES 1. OVER CURRENT RELAYS 2. CURRENT DIFFERENTIAL RELAYS OVER CURRENT RELAY: QLM: NAME: OVER CURRENT RELAY OF FEEDING POWER CIRCUIT LOCATION: TR PANEL NORMAL POSITION: DE-ENERGIZE INDICATION: DJ-TRIP RATING: 325 AMPS – WAG5/WAM4/WAP1 450 AMPS – WAG7/WAP4

4. QLA: NAME: OVER CURRENT RELAY OF AUXILARY POWER CIRCUIT LOCATION: TR PANEL NORMAL POSITION: DE-ENERGIZE INDICATION: DJ-TRIP RATING: 1400 AMPS – WAG5/WAM4/WAP1 2000 AMPS – WAG7/WAP4 QRSI: NAME: OVER CURRENT RELAY OF RSI BLOCK LOCATION: TR PANEL NORMAL POSITION: DE-ENERGIZE INDICATION: DJ-TRIP RATING: 3600 AMPS – WAG5/WAMP4/WAP1 4000 AMPS – WAG7/WAP4

5. QE: NAME: OVER CURRENT RELAY OF EXITATION LOCATION: CORRIDOR NO.2 ON HT3 COMPARTMENT NORMAL POSITION: DE-ENERGIZE INDICATION: RB-CUTOFF AND AUTO REGRESSION OF GR RATING: 900 AMPS – ALL LOCOS QF: NAME: OVER CURRENT RELAY OF BRAKING RESISTANCE LOCATION: CORRIDOR NO.2 ON HT3 COMPARTMENT NORMAL POSITION: DE-ENERGIZE INDICATION: RB-CUTOFF AND AUTO REGRESSION OF GR RATING: 700 AMPS INSIDE DBR 850 AMPS ROOF MOUNTED DBR

6. QD1: NAME: CURRENT DIFFRENTIAL RELAY OF TRACTION MOTOR 2&3 LOCATION: HT1 COMPARTMENT NORMAL POSITION: DE-ENERGIZE INDICATION: LSP GLOWS ( LAMP SIGNAL FOR WHEEL SLIPING ) AUTO REGRESSION OF GR AUTO SANDING RATING: 160/130 AMPS FOR GOODS LOCO 125/80 AMPS FOR COACHING LOCO QD2: NAME: CURRENT DIFFRENTIAL RELAY OF TRACTION MOTOR 4&5 LOCATION: HT3 COMPARTMENT NORMAL POSITION: DE-ENERGIZE INDICATION: LSP GLOWS ( LAMP SIGNAL FOR WHEEL SLIPING ) AUTO REGRESSION OF GR AUTO SANDING RATING: 160/130 AMPS FOR GOODS LOCO 125/80 AMPS FOR COACHING LOCO

7. VOLTAGE RELAY IT IS DEVIDED IN TO 2 TYPES 1. OVER VOLTAGE RELAY – Q-20 2. NO/LOW VOLTAGE RELAY – Q-30 Q-20 NAME: OVER VOLTAGE RELAY OF TRACTION MOTOR LOCATION: HT3 COMPARTMENT NORMAL POSITION: DE-ENERGIZE INDICATION: LSOV GLOW SUN BUZZER SOUNDING AUTO REGRESSION OF GR RATING: 865/750 VOLTS

8. Q-30 NAME: NO/LOW VOLTAGE RELAY OF OHE LOCATION: TR PANNEL NORMAL POSITION: ENERGIZE INDICATION: DJ-TRIP RATING: 2 65/215 VOLTS = 25/17.5 KV

9. SIGNALING RELAY LSDJ – QV-60 LSCHBA – QV-61 LSGR – QV-62 LSRSI – QV-63 LSB – QV-64 LSP – Q-48 CONTROL RELAYS Q-49 – GR SYNCHRONISING RELAY Q-50 – SUPERVISING REALY FOR TRACTION/BRAKING Q-51 – AUTO REGRESSION RELAY Q-52 – NOTCH BY NOTCH PROGRESSION/REGRESSION RELAY Q-100 – AUXILARY CONTROL RELAY

10. Q-118 – AUXILARY PROTECTION RELAY (5 SEC) Q-44 – GR HALF NOTCH PROTECTION RELAY ( 0.6 SEC ) Q-46 – GR FULL NOTCH PROTECTION RELAY QCVAR – ARNO PROTECTION RELAY QOA – BONDING RELAY FOR AUXILARIES QOP-1 – BONDING REALY FOR TRACTION POWER CIRCUIT-1 QOP-2 – BONDING RELAY FOR TRACTION POWER CIRCUIT-2

11. MECHANICAL RELAYS 1. CIRCULATION RELAY QVMT1 – MVMT1 QVMT2 – MVMT2 QVRH – MVRH QVSL1 – MVSL1 QVSL2 – MVSL2 QVSI1 – MVSI1 QVSI2 – MVSI2 2. PRESSURE RELAY QPH – MPH QPDJ – DJ ( RS )