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79-603: MX3000 is an electric train used on Oslo Metro in Oslo , Norway . The multiple units are produced by Siemens Mobility , who started serial delivery in 2007. Seventy-eight three-car units were ordered by Sporveien , and five by Akershus County Municipality . They replaced the older T1000 and T1300 stock that was used on the Oslo Metro since 1966. By 2010, the last T1000 and T1300 trains had been retired and replaced by 83 three-car units. 32 additional sets were ordered, and

158-573: A v {\displaystyle V_{\mathrm {av} }} results from the integral under the graph of a positive half-wave with the period duration of 2 3 π {\displaystyle {\frac {2}{3}}\pi } (from 30° to 150°): If the AC supply is fed via a transformer with a center tap, a rectifier circuit with improved harmonic performance can be obtained. This rectifier now requires six diodes, one connected to each end of each transformer secondary winding . This circuit has

237-437: A distributed system connected by a double multifunction vehicle bus. It has two vehicle control units, that monitor and control all main functions of the train; in addition, there are systems for controlling the brakes, traction, doors, ventilation, passenger information system and compressor. Like the older stock, the train's speed is controlled by an automatic train protection (ATP) system. The speed codes are transferred from

316-402: A three-phase supply . Rectifiers yield a unidirectional but pulsating direct current; half-wave rectifiers produce far more ripple than full-wave rectifiers, and much more filtering is needed to eliminate harmonics of the AC frequency from the output. The no-load output DC voltage of an ideal half-wave rectifier for a sinusoidal input voltage is: where: A full-wave rectifier converts

395-509: A " cat's whisker " of fine wire pressing on a crystal of galena (lead sulfide) to serve as a point-contact rectifier or "crystal detector". Rectifiers have many uses, but are often found serving as components of DC power supplies and high-voltage direct current power transmission systems. Rectification may serve in roles other than to generate direct current for use as a source of power. As noted, rectifiers can serve as detectors of radio signals. In gas heating systems flame rectification

474-421: A circuit as a split rail power supply. A variant of this is to use two capacitors in series for the output smoothing on a bridge rectifier then place a switch between the midpoint of those capacitors and one of the AC input terminals. With the switch open, this circuit acts like a normal bridge rectifier. With the switch closed, it acts like a voltage doubling rectifier. In other words, this makes it easy to derive

553-460: A full-wave bridge circuit. Thyristors are commonly used in place of diodes to create a circuit that can regulate the output voltage. Many devices that provide direct current actually 'generate' three-phase AC. For example, an automobile alternator contains nine diodes, six of which function as a full-wave rectifier for battery charging. An uncontrolled three-phase, half-wave midpoint circuit requires three diodes, one connected to each phase. This

632-417: A maximum axle load of 12.5 tonnes (12.3 long tons; 13.8 short tons). Each three-car unit has 138 seats, and a total capacity of 493 passengers. The height of the floor is 1.12 meters (3 ft 8 in) above the track, allowing step-free access to the platforms. There are three doors on each side of each car, measuring 1,300 millimeters (51 in) wide and 1,960 millimeters (77 in) high. Unlike

711-483: A motor-driving car or power-driving car. On third rail systems, the outer vehicles usually carry the pick up shoes with the motor vehicles receiving the current via intra-unit connections . Many modern two-car EMU sets are set up as twin or "married pair" units. While both units in a married pair are typically driving motors, the ancillary equipment (air compressor and tanks, batteries and charging equipment, traction power and control equipment, etc.) are shared between

790-448: A power output of 1,680 kilowatts (2,250 hp). In each car, the four motors are fed by the car's own insulated-gate bipolar transistor . They transform the 750  volt direct current collected from the third rail shoe to the three-phase alternating current used in the motors. The frequency and amplitude of the current fed to the engines varies depending on the train's speed. The MX3000 introduced regenerative brakes , that allow

869-414: A pulse-number of six, and in effect, can be thought of as a six-phase, half-wave circuit. Before solid state devices became available, the half-wave circuit, and the full-wave circuit using a center-tapped transformer, were very commonly used in industrial rectifiers using mercury-arc valves . This was because the three or six AC supply inputs could be fed to a corresponding number of anode electrodes on

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948-457: A series connection of two three-pulse center circuits. For low-power applications, double diodes in series, with the anode of the first diode connected to the cathode of the second, are manufactured as a single component for this purpose. Some commercially available double diodes have all four terminals available so the user can configure them for single-phase split supply use, half a bridge, or three-phase rectifier. For higher-power applications,

1027-426: A single discrete device is usually used for each of the six arms of the bridge. For the very highest powers, each arm of the bridge may consist of tens or hundreds of separate devices in parallel (where very high current is needed, for example in aluminium smelting ) or in series (where very high voltages are needed, for example in high-voltage direct current power transmission). The pulsating DC voltage results from

1106-436: A single tank, sharing a common cathode. With the advent of diodes and thyristors, these circuits have become less popular and the three-phase bridge circuit has become the most common circuit. For an uncontrolled three-phase bridge rectifier, six diodes are used, and the circuit again has a pulse number of six. For this reason, it is also commonly referred to as a six-pulse bridge . The B6 circuit can be seen simplified as

1185-713: A situation with only three-car trains on the Lambertseter Line , the Ring Line and the Kolsås Line (lines 4, 5 and 3) would only use three-car trains. The MX3000 is a three-car electric multiple unit built exclusively for the Oslo Metro by Siemens in Vienna , Austria. It is a modification of trains used on the Vienna U-Bahn . The units are designed by Porsche Design Studio . Unlike the red predecessors,

1264-408: A supply transformer that produces a 30° phase shift between the two bridges. This cancels many of the characteristic harmonics the six-pulse bridges produce. The 30-degree phase shift is usually achieved by using a transformer with two sets of secondary windings, one in star (wye) connection and one in delta connection. The simple half-wave rectifier can be built in two electrical configurations with

1343-505: A trailing boost stage or primary high voltage (HV) source, are used in HV laser power supplies, powering devices such as cathode-ray tubes (CRT) (like those used in CRT based television, radar and sonar displays), photon amplifying devices found in image intensifying and photo multiplier tubes (PMT), and magnetron based radio frequency (RF) devices used in radar transmitters and microwave ovens. Before

1422-436: A transformer without center tap), are needed. Single semiconductor diodes, double diodes with a common cathode or common anode, and four- or six- diode bridges are manufactured as single components. For single-phase AC, if the transformer is center-tapped, then two diodes back-to-back (cathode-to-cathode or anode-to-anode, depending on output polarity required) can form a full-wave rectifier. Twice as many turns are required on

1501-428: A voltage of roughly 320 V (±15%, approx.) DC from any 120 V or 230 V mains supply in the world, this can then be fed into a relatively simple switched-mode power supply . However, for a given desired ripple, the value of both capacitors must be twice the value of the single one required for a normal bridge rectifier; when the switch is closed each one must filter the output of a half-wave rectifier, and when

1580-467: Is 138 seats, and total capacity is 493 passengers. The first series of 33 units were ordered in 2003, followed by an additional order for 30 in 2005, 15 in 2008, and 32 in December 2010. Financed by Oslo Package 2 , each unit cost about 45 million  kr . In 1966, the Oslo Metro opened as an upgrade of two existing suburban tramways, the Østensjø- and Lambertseter Lines (Lines 3 and 4). By 1970,

1659-539: Is directly related to the DC current, and the above equation may be re-expressed as where: Although better than single-phase rectifiers or three-phase half-wave rectifiers, six-pulse rectifier circuits still produce considerable harmonic distortion on both the AC and DC connections. For very high-power rectifiers the twelve-pulse bridge connection is usually used. A twelve-pulse bridge consists of two six-pulse bridge circuits connected in series, with their AC connections fed from

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1738-502: Is known as rectification , since it "straightens" the direction of current. Physically, rectifiers take a number of forms, including vacuum tube diodes , wet chemical cells, mercury-arc valves , stacks of copper and selenium oxide plates , semiconductor diodes , silicon-controlled rectifiers and other silicon-based semiconductor switches. Historically, even synchronous electromechanical switches and motor-generator sets have been used. Early radio receivers, called crystal radios , used

1817-454: Is operated symmetrically (as positive and negative supply voltage), the center point of the rectifier on the output side (or the so-called isolated reference potential) opposite the center point of the transformer (or the neutral conductor) has a potential difference in the form of a triangular common-mode voltage . For this reason, these two centers must never be connected to each other, otherwise short-circuit currents would flow. The ground of

1896-515: Is required—e.g., where variable output voltage is needed. High-power rectifiers, such as those used in high-voltage direct current power transmission, employ silicon semiconductor devices of various types. These are thyristors or other controlled switching solid-state switches, which effectively function as diodes to pass current in only one direction. Rectifier circuits may be single-phase or multi-phase. Most low power rectifiers for domestic equipment are single-phase, but three-phase rectification

1975-417: Is simpler as no provision is needed for exhausting fumes, although retrofitting existing limited-clearance tunnels to accommodate the extra equipment needed to transmit electric power to the train can be difficult. Multiple unit train control was first used in the 1890s. The Liverpool Overhead Railway opened in 1893 with two-car electric multiple units, controllers in cabs at both ends directly controlling

2054-487: Is the simplest type of three-phase rectifier but suffers from relatively high harmonic distortion on both the AC and DC connections. This type of rectifier is said to have a pulse-number of three, since the output voltage on the DC side contains three distinct pulses per cycle of the grid frequency: [REDACTED] The peak values V p e a k {\displaystyle V_{\mathrm {peak} }} of this three-pulse DC voltage are calculated from

2133-434: Is used to detect the presence of a flame. Depending on the type of alternating current supply and the arrangement of the rectifier circuit, the output voltage may require additional smoothing to produce a uniform steady voltage. Many applications of rectifiers, such as power supplies for radio, television and computer equipment, require a steady constant DC voltage (as would be produced by a battery ). In these applications

2212-423: Is very important for industrial applications and for the transmission of energy as DC (HVDC). In half-wave rectification of a single-phase supply, either the positive or negative half of the AC wave is passed, while the other half is blocked. Because only one half of the input waveform reaches the output, mean voltage is lower. Half-wave rectification requires a single diode in a single-phase supply , or three in

2291-779: The China Railway High-speed in China, ICE 3 in Germany, and the British Rail class 395 Javelin. The retired New York–Washington Metroliner service, first operated by the Pennsylvania Railroad and later by Amtrak , also featured high-speed electric multiple-unit cars, known as the Budd Metroliner . EMUs powered by fuel cells are under development. If successful, this would avoid

2370-409: The electromagnetic brakes to feed power back to the power supply when braking. In addition, there is a back-up disc brake on each axle. Acceleration in the range 0 to 40 kilometers per hour (0 to 25 mph) is limited to 1.3  meters per second squared (4.3 ft/s). In this phase, the fully loaded train uses 5.0  kiloampere . For use in areas without a third rail, such as at depots ,

2449-505: The 100th set. Many of the train sets have also been given a girls' name. Electric multiple unit EMUs are popular on commuter, and suburban rail networks around the world due to their fast acceleration and pollution-free operation, and are used on most rapid-transit systems. Being quieter than diesel multiple units (DMUs) and locomotive -hauled trains, EMUs can operate later at night and more frequently without disturbing nearby residents. In addition, tunnel design for EMU trains

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2528-450: The 1960s through the 80s. During the first 30 days, two errors occurred: one in the closing mechanism of the doors, and one with a switch in the cab that was not water tight. However, it turned out that Oslo Sporveier had not been accurate enough in specifying the energy consumption of the trains, and the rectifiers on parts of the line needed to be upgraded to supply sufficient power to the trains. During 2007, there were four incidents where

2607-419: The 80/5Y3 (4 pin)/(octal) were popular examples of this configuration. Single-phase rectifiers are commonly used for power supplies for domestic equipment. However, for most industrial and high-power applications, three-phase rectifier circuits are the norm. As with single-phase rectifiers, three-phase rectifiers can take the form of a half-wave circuit, a full-wave circuit using a center-tapped transformer, or

2686-488: The ATP points in the infrastructure, using 75  hertz pulses in the tracks. The trains pick up the signals via antennas. The speed codes are 15 km/h (9.3 mph), 30 km/h (19 mph), 50 km/h (31 mph) and 70 km/h (43 mph). They are informed to the engineer via signals in the driver's cab; in addition, the system will automatically reduce the speed, should the limit be exceeded. The driver can put

2765-627: The MX3000, increasing the quantity by another 30 units. With the second order, the price had increased to NOK 2.5 billion. Two test units were delivered in October 2005, and the serial production started in April 2006, with the first deliveries in April 2007. With the delivery of the new trains, Oslo Sporveier received criticism that they had been disloyal to the old red color of the metro, and that they did not follow up on their former design concept from

2844-673: The Oslo-owned units, Akershus' five units are owned by the transit authority Ruter . The same year, the city council in Oslo decided to upgrade the Holmenkoll Line to metro standard, to allow six-car MX3000 trains to be the main mode of transport to Holmenkollen during the FIS Nordic World Ski Championships 2011 . This allowed 9,000 people per hour to be transported to the sports venue. In 2009,

2923-620: The RMS value V L N {\displaystyle V_{\mathrm {LN} }} of the input phase voltage (line to neutral voltage, 120 V in North America, 230 V within Europe at mains operation): V p e a k = 2 ⋅ V L N {\displaystyle V_{\mathrm {peak} }={\sqrt {2}}\cdot V_{\mathrm {LN} }} . The average no-load output voltage V

3002-546: The T2000 units were taken out of service, and on 22 April 2010 the last T1300 was taken out of service, making the MX3000 the only units in traffic on the Oslo Metro. The city council was considering ordering 15 additional MX3000 to replace the T2000, as an alternative for a NOK 50-million renovation. In November 2010, the Accident Investigation Board Norway criticized the braking system of

3081-413: The batteries are charged via the electric pickup when operating on electric mode. EMUs, when compared with electric locomotives , offer: Electric locomotives, when compared to EMUs, offer: Rectifier A rectifier is an electrical device that converts alternating current (AC), which periodically reverses direction, to direct current (DC), which flows in only one direction. The process

3160-404: The bogies is 11.00 meters (36 ft 1 in). The primary suspension is steel coil spring between the axles and the bogies, with a secondary air suspension between the frame and the bogies. The latter, which the MX3000 was the first to use on the metro, gives reduced noise, better comfort and makes it possible to adjust the height with changed passenger weight. The units are controlled by

3239-404: The circuit is operated asymmetrically (as a simple supply voltage with just one positive pole), both the positive and negative poles (or the isolated reference potential) are pulsating opposite the center (or the ground) of the input voltage analogously to the positive and negative waveforms of the phase voltages. However, the differences in the phase voltages result in the six-pulse DC voltage (over

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3318-485: The construction of electric traction railways and trolley systems worldwide. Each car of the train has its own traction motors: by means of motor control relays in each car energized by train-line wires from the front car all of the traction motors in the train are controlled in unison. The cars that form a complete EMU set can usually be separated by function into four types: power car, motor car, driving car, and trailer car. Each car can have more than one function, such as

3397-462: The differences of the instantaneous positive and negative phase voltages V L N {\displaystyle V_{\mathrm {LN} }} , phase-shifted by 30°: [REDACTED] The ideal, no-load average output voltage V a v {\displaystyle V_{\mathrm {av} }} of the B6 circuit results from the integral under the graph of a DC voltage pulse with

3476-415: The diodes pointing in opposite directions, one version connects the negative terminal of the output direct to the AC supply and the other connects the positive terminal of the output direct to the AC supply. By combining both of these with separate output smoothing it is possible to get an output voltage of nearly double the peak AC input voltage. This also provides a tap in the middle, which allows use of such

3555-442: The duration of a period). The strict separation of the transformer center from the negative pole (otherwise short-circuit currents will flow) or a possible grounding of the negative pole when powered by an isolating transformer apply correspondingly to the symmetrical operation. The controlled three-phase bridge rectifier uses thyristors in place of diodes. The output voltage is reduced by the factor cos(α): Or, expressed in terms of

3634-508: The eastern lines to have a 7-minute-30-second headway on their services into the city center, instead of the current 15-minute headway. Trains would start using the balloon loop located at Stortinget , and the western lines would continue to have a 15-minute headway. Additionally, the trains serving the Ring Line were extended to six cars, with a double train set. The order cost NOK 675 million. In addition, Akershus finalized their order for five units, costing NOK 240 million. Unlike

3713-555: The employees, who performed a partial strike by refusing to work overtime. As a result, after a few weeks, the company lacked 57 trains to provide adequate service. The issue was solved when the socialist opposition parties along with the Liberal Party agreed to postpone the matter until after all the new trains were delivered in 2009. As part of the agreement, a new limited company, Oslo Vognselskap, wholly owned by Sporveien, would take ownership of all metro trains and trams used by

3792-427: The final train set was delivered in 2014, increasing the fleet to 115 units. The trains are built as 3-car units, though they often operate 2 coupled units in regular service. The units are 54.34 metres (178 ft 3 in) long, and weigh 98 tonnes (96 long tons; 108 short tons) empty. They have twelve 140-kilowatt (190 hp) traction motors, allowing speeds of 70 kilometres per hour (43 mph). Seated capacity

3871-554: The introduction of semiconductor electronics, transformerless vacuum tube receivers powered directly from AC power sometimes used voltage doublers to generate roughly 300 VDC from a 100–120 V power line. Several ratios are used to quantify the function and performance of rectifiers or their output, including transformer utilization factor (TUF), conversion ratio ( η ), ripple factor, form factor, and peak factor. The two primary measures are DC voltage (or offset) and peak-peak ripple voltage, which are constituent components of

3950-450: The introduction of semiconductor electronics, vacuum tube rectifiers became obsolete, except for some enthusiasts of vacuum tube audio equipment . For power rectification from very low to very high current, semiconductor diodes of various types ( junction diodes , Schottky diodes , etc.) are widely used. Other devices that have control electrodes as well as acting as unidirectional current valves are used where more than simple rectification

4029-451: The line to line input voltage: where: The above equations are only valid when no current is drawn from the AC supply or in the theoretical case when the AC supply connections have no inductance. In practice, the supply inductance causes a reduction of DC output voltage with increasing load, typically in the range 10–20% at full load. The effect of supply inductance is to slow down the transfer process (called commutation) from one phase to

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4108-416: The need for an overhead line or third rail . An example is Alstom ’s hydrogen -powered Coradia iLint . The term hydrail has been coined for hydrogen-powered rail vehicles. Many battery electric multiple units are in operation around the world, with the take up being strong. Many are bi-modal taking energy from onboard battery banks and line pickups such as overhead wires or third rail. In most cases

4187-420: The next. As result of this is that at each transition between a pair of devices, there is a period of overlap during which three (rather than two) devices in the bridge are conducting simultaneously. The overlap angle is usually referred to by the symbol μ (or u), and may be 20 30° at full load. With supply inductance taken into account, the output voltage of the rectifier is reduced to The overlap angle μ

4266-459: The older T1000 trains, the triple-car configuration allows passengers to walk between the cars. Combined with a better spatial design, it reduces the feeling of crowding. The MX3000 also introduced air conditioning in the driver's cab. The units run either in single configuration (with three cars) or in multiple (with six cars). Each car is equipped with four three-phase asynchronous 140-kilowatt (190 hp) motors , giving each three-car unit

4345-454: The operating companies Oslo T-banedrift and Oslo Sporvognsdrift , the latter being the operator of the tramway . Responsibility for the debt accumulated after buying the trains was to be managed by Oslo Vognselskap, while operation and management of the maintenance contracts was transferred to Oslo T-banedrift. In January 2008, an additional 15 units were ordered by Oslo Municipality, with an option for further orders later. This would allow all

4424-510: The order for the MX3000 trains was placed, the Kolsås- and Holmenkoll Lines still used overhead wires, and would not be able to use the new stock. Both systems were at the time being considered for conversion to light rail systems, that would connect to the Lilleaker- and Ullevål Hageby Line , respectively. The old fleet of T1000 and T1300 consisted of 195 cars in eight series. The T1000

4503-553: The outer end of the pair, saving space and expense over a cab at both ends of each car. Disadvantages include a loss of operational flexibility, as trains must be multiples of two cars, and a failure on a single car could force removing both it and its partner from service. Some of the more famous electric multiple units in the world are high-speed trains: the Italian Pendolino and Frecciarossa 1000 , Shinkansen in Japan,

4582-655: The output of the rectifier is smoothed by an electronic filter , which may be a capacitor , choke , or set of capacitors, chokes and resistors , possibly followed by a voltage regulator to produce a steady voltage. A device that performs the opposite function, that is converting DC to AC, is called an inverter . Before the development of silicon semiconductor rectifiers, vacuum tube thermionic diodes and copper oxide- or selenium-based metal rectifier stacks were used. The first vacuum tube diodes designed for rectifier application in power supply circuits were introduced in April 1915 by Saul Dushman of General Electric. With

4661-403: The output voltage. Conversion ratio (also called "rectification ratio", and confusingly, "efficiency") η is defined as the ratio of DC output power to the input power from the AC supply. Even with ideal rectifiers, the ratio is less than 100% because some of the output power is AC power rather than DC which manifests as ripple superimposed on the DC waveform. The ratio can be improved with

4740-419: The peak value of the phase input voltage V p e a k {\displaystyle V_{\mathrm {peak} }} and is calculated with V p e a k {\displaystyle V_{\mathrm {peak} }} minus half of the DC voltage at 60° of the period: The RMS value of the common-mode voltage is calculated from the form factor for triangular oscillations: If

4819-412: The period duration of 1 3 π {\displaystyle {\frac {1}{3}}\pi } (from 60° to 120°) with the peak value v ^ D C = 3 ⋅ V p e a k {\displaystyle {\hat {v}}_{\mathrm {DC} }={\sqrt {3}}\cdot V_{\mathrm {peak} }} : If the three-phase bridge rectifier

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4898-485: The switch is open the two capacitors are connected in series with an equivalent value of half one of them. In a Cockcroft-Walton voltage multiplier , stages of capacitors and diodes are cascaded to amplify a low AC voltage to a high DC voltage. These circuits are capable of producing a DC output voltage potential up to about ten times the peak AC input voltage, in practice limited by current capacity and voltage regulation issues. Diode voltage multipliers, frequently used as

4977-571: The system was supplemented by the Grorud- and Furuset Lines . They only operated to the eastern suburbs. In 1987, the system was expanded to connect to the western network, that remained a suburban tramway with overhead wires , two-car platforms and an inferior signaling system. In 1993, the Sognsvann Line was converted to metro standard , with the Røa Line following two years later. When

5056-455: The three-phase bridge rectifier in symmetrical operation is thus decoupled from the neutral conductor or the earth of the mains voltage. Powered by a transformer, earthing of the center point of the bridge is possible, provided that the secondary winding of the transformer is electrically isolated from the mains voltage and the star point of the secondary winding is not on earth. In this case, however, (negligible) leakage currents are flowing over

5135-487: The total order up to 115 three-car units. The last trains would be delivered by 2012. There was political disagreement regarding the final purchase, with the Liberal Party and socialist opposition securing a majority for the purchase, while the right-winged parties voted to order 19 units. The extra trains will make it possible to run all lines except the Holmenkollen Line (Line 1) with six-car lines, compared to

5214-568: The traction current to motors on both cars. The multiple unit traction control system was developed by Frank Sprague and first applied and tested on the South Side Elevated Railroad (now part of the Chicago 'L' ) in 1897. In 1895, derived from his company's invention and production of direct current elevator control systems, Frank Sprague invented a multiple unit controller for electric train operation. This accelerated

5293-484: The trains are equipped with a 110 V battery. This removes the need for shunting at the depots, and makes maintenance more cost efficient. Energy usage is reduced by 30%, estimated to save the operating company NOK 13 million per year, compared to using the old stocks. There are two bogies per car, each with two axles . The wheel diameter is 850 millimeters (33 in) for new wheels, and 770 millimeters (30 in) when fully worn-down. The center distance between

5372-542: The trains are painted white with black and grey detailing. The chassis is in aluminum. A three-car train is 54.34 meters (178 ft 3 in) long; the end cars are 18.21 meters (59 ft 9 in) long each, while the center car is 17.92 meters (58 ft 10 in) long. The cars are 3.16 meters (10 ft 4 in) wide and 3.68 meters (12 ft 1 in) tall. An empty three-car unit weighs 98 tonnes (96 long tons; 108 short tons), while it with full payload weighs 147 tonnes (145 long tons; 162 short tons). This gives

5451-492: The trains in an automatic mode, where the train itself adjusts the trains speed to the speed limit. The driver is always responsible for starting and halting the train at stations. The driver's cabs are more ergonomic than in the T1000, and the mirrors to monitor the platforms have been replaced with cameras and screens. The MX3000 carriage numbers range from 3x01–3x99 (first 99 sets) and continued with 3x100–3x115 upon delivery of

5530-498: The trains were not able to brake at stations. The worst incident occurred when a train slid 1.3 kilometres (0.81 mi) from Blindern down to Majorstuen . Following the 2006 decision to convert the Kolsås Line to metro standard, Akershus County Council announced that they would order five units. In November 2006, the city government proposed that the maintenance of the new trains be privatized . This resulted in protests from

5609-430: The trains. In 2009, there were 83 incidents where trains with locked wheels slid down steep sections of track. The Accident Investigation Board found that the metro had conducted insufficient testing of the braking system on steep slippery lines, had not adjusted the brakes satisfactorily, and had not maintained the trains and tracks sufficiently. In December 2010, Oslo Vognselskap ordered another 32 three-car units, bringing

5688-420: The transformer secondary to obtain the same output voltage than for a bridge rectifier, but the power rating is unchanged. The average and RMS no-load output voltages of an ideal single-phase full-wave rectifier are: Very common double-diode rectifier vacuum tubes contained a single common cathode and two anodes inside a single envelope, achieving full-wave rectification with positive output. The 5U4 and

5767-459: The transformer windings. The common-mode voltage is formed out of the respective average values of the differences between the positive and negative phase voltages, which form the pulsating DC voltage. The peak value of the delta voltage v ^ c o m m o n − m o d e {\displaystyle {\hat {v}}_{\mathrm {common-mode} }} amounts ⁠ 1 / 4 ⁠ of

5846-426: The two cars in the set. Since neither car can operate without its "partner", such sets are permanently coupled and can only be split at maintenance facilities. Advantages of married pair units include weight and cost savings over single-unit cars (due to halving the ancillary equipment required per set) while allowing all cars to be powered, unlike a motor-trailer combination. Each car has only one control cab, located at

5925-414: The use of smoothing circuits which reduce the ripple and hence reduce the AC content of the output. Conversion ratio is reduced by losses in transformer windings and power dissipation in the rectifier element itself. This ratio is of little practical significance because a rectifier is almost always followed by a filter to increase DC voltage and reduce ripple. In some three-phase and multi-phase applications

6004-431: The whole of the input waveform to one of constant polarity (positive or negative) at its output. Mathematically, this corresponds to the absolute value function. Full-wave rectification converts both polarities of the input waveform to pulsating DC (direct current), and yields a higher average output voltage. Two diodes and a center-tapped transformer , or four diodes in a bridge configuration and any AC source (including

6083-541: The work to establish a financing package for new investments in public transport in Akershus and Oslo started. It was passed, in 2001, by the city and county councils, as well as the Norwegian Parliament . Oslo Package 2 allowed municipal and state grants to be supplemented by increased fare and toll road revenue to finance, among other things, new trains for the metro. The initial order by Oslo Sporveier

6162-430: Was for 33 units (or 99 cars), and was approved by the board on 28 June 2003. The initial order cost NOK 1.6 billion, and included options for further orders. Five other manufactures had been rejected during the procurement process. Combined with other investments in the network, the new trains will allow faster travel times on the metro. In 2005, the city council voted to replace all existing T1000 and T1300 stock with

6241-630: Was the original series delivered between 1966 and 1978, while the T1300 was a later adoption built until 1987. The T1000 series had only a third rail shoe, while the T1300 also had a pantograph , and could be used on the Kolsås- and Holmenkoll Lines. In 1995, six two-car T2000 units were delivered for the Holmenkoll Line. They were, at the time, proposed as a possible replacement for all the T1000 and T1300 stock, but were prone to technical problems. They featured both third rail shoes and pantographs. In 1996,

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