The Indian locomotive class WCAM-1 was a class of dual-voltage (25 kV AC and 1.5 kV DC) electric locomotives that was developed in 1973 by Chittaranjan Locomotive Works for Indian Railways. The model name stands for broad gauge (W), DC Current (C), AC Current (A), Mixed traffic (M) locomotive, 1st generation (1). They entered service in March 1973. A total of 53 WCAM-1 were built at CLW between 1973 and 1979, which made them the most numerous class of mainline dual-power AC-DC electric locomotive.
The WCAM-1 was one of the most successful locomotives of Indian Railways, having served both passenger and freight trains for over 40 years between 1973 and 2015. This class was a bi-current version of the WAM-4 class. However, with the advent of new 3-phase locomotives like WAP-5 and WAP-7, the aging fleet of WCAM-1 locomotives were relegated to hauling smaller passenger trains and have been fully withdrawn from mainline duties. All units have been scrapped with no locomotives preserved.
The WCAM-1 was a class of locomotive used in the Indian Railways system. They were the first locomotives from the WCAM class. These locos were operational in routes around Mumbai. These locomotives worked on both AC as well as DC as their classification suggested.[4] They hauled trains from DC section of suburban railway to AC section and thus performed a very critical task as they could easily operate on both AC and DC. However they performed poorly in DC mode compared to AC mode but they were very robust and had easy operating and handling characteristics.
These were 1st class of Wide Gauge's (W) Bi-current charged (CA - runs both under AC and DC) and Mixed load series (M - hauls both passenger and freight trains). These were the first electric locomotives to enter Western Railway's Mumbai division; prior to that steam and diesel locomotives used to haul trains in Western Railway's Mumbai division. These brought an end to the steam era in this division. They were also the first locomotives allotted to Valsad (BL) shed. Their top speed under DC was the lowest, as compared to other Bi-current charged locomotives. They were the first Bi-current charged locomotives in the country. Initially all were vacuum braked but were retrofitted with air brakes to make them dual braked. Some also had their vacuum brakes replaced with air brakes. Introduced in 1975. One of the single pantographs on the WCAM-1 is used in DC traction; the other one carries AC current. The two pantographs were not identical, though similar in design. Originally built with vacuum brakes only, although a few (Nos. 21805, 21807, 21812, 21828, 21838, 21844, 21845, and 21850) had both vacuum and air brakes. They lacked dynamic brakes. The WCAM-1 did not use a variable ratio auto-transformer in AC mode like the others; it used a fixed-ratio transformer and rectifier bank to convert the OHE supply to 1500 V DC. The design of the transformers and notches made this a hard machine to operate, with the fusible links tending to blow often. Of the 28 notches, notches 4, 14, 21, and 28 were used for continuous operation, although notch 4 was intended for low-speed shunting and was very ineffective. Notches 14, 21, and 28 were the terminal notches of the series, series-parallel, and parallel circuit notch sequences. In DC mode, the WCAM-1 used resistor banks for speed control. However they were very robust machines and relatively easy in the handling characteristics. WCAM-1's had three traction modes (series, series-parallel, parallel) in both DC and AC mode, but using the parallel mode in DC was discouraged because of power problems. In practice this was not restrictive since series-parallel notches allowed reaching 75 km/h or so. In AC mode, the locos were almost always used with the motors in all-parallel mode. Unlike the WCAM-2 and WCAM-3 locos, no reconfiguration has been carried out to force the use of all-parallel mode with AC. Weak field operation was available. They were briefly tried out for freight use by CR, but all finally ended up with WR. The top ones getting the WCAM-2P (see below). [5/02] However, CR's Indore-Pune weekly train had been hauled by a WR WCAM-1. Max. speed 100 km/h, 110 km/h after regearing. Traction motors were nose-suspended and axle-hung.
Of all the 30 notches, 1-21 were DC notches allowing series operation of traction motors. Rest of the 8 notches allow series-parallel combination under DC. Under AC, the combinations were 3S-2P and 2S-3P. These locomotives could run in parallel combination but it was discouraged due to power problems under DC. Under AC, the locomotives were run under parallel notches nearly always. Although these engines were not rebuilt to use only parallel combination under AC. Field weakening of traction motors was possible at 21st and 30th notches. Voltage control was done by Tap changer operation under AC and Resistance notching under DC. Traction motors were charged by DC. Its prototypes were tested in the year 1971.[5][6]
Traction Motors
Alstom/CLW TAO 659 A1 2,800 kg (6,200 lb). Axle-hung, nose-suspended and force ventilated. Temperature rise by resistance in Armature - 140 degrees Celsius (284 degrees Fahrenheit)/Field - 160 °C (320 °F). Coil resistance at 110 °C (230 °F) in Armature - 0.0151 ohms/Main pole - 0.0145 ohms/Interpole - 0.0078 ohms. Starting current - 1100 A. 1 hour rating - 798 hp (595 kW), 750 V, 870 A and 1070 RPM. Continuous rating - 585 kW (784 hp), 550 V, 840 A and 1095 RPM. Air gap in main pole - 5.5 mm (0.217 in)/Interpole - 6 mm (0.236 in). Grade of brushes - EG 367, 6 brush holders and 3 brush per holder
Gear Ratio
61:16, 58:21
Transformer
BHEL made BOT 34600. 11,500 kg (25,400 lb), Forced Oil cooling, Class 'A' insulation and 32 taps. Primary rating - 3646 kVA, 22.5 kV and 162 A. Secondary rating - 3460 kVA, 1730 V (DC) and 2x1000 A (DC). Tertiary rating - 274 kVA, 1470 V and 186 A
Silicon Rectifiers
48 cells (321 UFR200) per bridge. Continuous rating - 1000 A each cubicle. 1 hour rating - 1270 V. Max starting current - 1650 A. Forced air cooling.
2 Headlights (750 W and 32 V). Lead Acid battery (50 cells), Rating - 110 V and 5 hours.
Motor-Alternator Set
SOA-749 Alternator by Kirloskar Group (180 kVA, 400 V, 270 A, 1500 RPM and 3 phase). AY100AZ Motor by AEI (2,106 hp or 1,570 kW, 1500 RPM, 1400 V and 136 A continuous).
Number of sand boxes
16
Main Starting Resistance blower
Four PETA-60 types by SF Product (11,400 m3/h or 400,000 cu ft/h). ILA2-116.2 type Motor by Siemens(9.3 kW or 12 hp, 400 V, 18 A and 2925 RPM).
Auxiliary Rectifier
Rating with 2 bridges in parallel - 180 A (Continuous) and 1000 A (5 seconds)/1 bridge - 90 A (Continuous), 140 A (30 minutes) and 900 A (2 seconds). Natural Air cooling. Twenty four 324-UFR200 type cells connected by bridges.
2EC388 type Compressor by Kirloskar
Rating - 792 L/min (174 imp gal/min; 209 US gal/min) at 7 kg/cm2 (100 psi). Motor - 7.5 kW or 10 hp, 38 V, 15 A and 1390 RPM.
2 Exhausters by Gresham and Craven
Northey-250RE type. Two 385 V motors.
2 Traction Motor Blowers by SF Product
MLBRX-42.5-1-H4 type (16,200 m3/h or 570,000 cu ft/h). 2 Motors by Siemens(22 kW (30 hp), 385 V, 41 A and 3000 RPM).
PFTA-50 Arr 6 type Smoothing Reaction Blower by SF Product
Capacity - 4,200 m3/h (150,000 cu ft/h). Motor - 2.2 hp (2 kW), 380 V and 2860 RPM
MLBR-60-1-H2 type Oil Cooler Blower by SF Product
Capacity - 22,200 m3/h (29,000 cuyd/h). Motor - 22 kW (30 hp), 380 V, 43 A and 1470 RPM
2 Silicon Rectifier Blowers by SF Product
PHMX-40-6 type (3,400 m3/h or 120,000 cu ft/h). 2 Motors - 2 kW (3 hp), 380 V, 4.4 A and 2860 RPM.
Oil Pump by Best and Company Private Limited
Capacity - 750 L/min (160 imp gal/min; 200 US gal/min) Motor - 3.3 kW (4 hp), 380 V, 66 A and 2865 RPM
SL-42 type Smoothing Reactor
Rating - 1250 V and 950 A. 0.00718 ohms resistance at 110 °C (230 °F).
All 53 WCAM-1s were based at Valsad Electric Loco Shed in Gujarat, and were withdrawn from service after the conversion of entire Mumbai region into AC traction.
The WCAM-1 were employed on all express trains, including Shatabdi and Rajdhani Express (till Vadodara), until AC electrification of Mumbai area. The arrival of WCAM-2P engines did not reduce their work loads. Later on, with introduction of more modern AC locomotives and need for faster trains, the WCAM-1s were relegated to secondary passenger trains, including:
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