Project-1: Powertrain for aircraft in runways
Study 1:To list out the total weight of various types of aircrafts.
Solution:
The maximum take-off weight (MTOW) or maximum gross take-off weight (MGTOW) or maximum take-off mass (MTOM) of an aircraft is the maximum weight at which the pilot is allowed to attempt to take off, due to structural or other limits.
MLW = Maximum landing weight
The various types of aircrafts and their total / (maximum gross take-off weight (MGTOW) are listed below:
|
TYPE |
MTOW (Kg) |
MLW(tonnes) |
|
640,000 |
591.7 |
|
|
589,670 |
||
|
575,000 |
394 |
|
|
447,700 |
346.091 |
|
|
Antonov An-124-100M |
405,060 |
330 |
|
396,900 |
295.742 |
|
|
381,000 |
288.417 |
|
|
377,840 |
285.700 |
|
|
377,840 |
260.320 |
|
|
371,950 |
240 |
|
|
347,800 |
260.816 |
|
|
352,000 |
251.5 |
|
|
351,800 |
251.29 |
|
|
347,450 |
223.168 |
|
|
340,200 |
265.300 |
|
|
308,000 |
233.5 |
|
|
299,370 |
237.683 |
|
|
297,550 |
213.00 |
|
|
276,700 |
190 |
|
|
273,300 |
185 |
|
|
270,000 |
175 |
|
|
270,000 |
195.04 |
|
|
256,280 |
183 |
|
|
254,000 |
192.777 |
|
|
254,000 |
201.849 |
|
|
253,500 |
181 |
|
|
250,000 |
175 |
|
|
242,000 |
185 |
|
|
242,000 |
180 |
|
|
231,300 |
166.92 |
|
|
228,000 |
172.365 |
|
|
211,400 |
||
|
208,000 |
175 |
|
|
204,000 |
158.758 |
|
|
192,000 |
140 |
|
|
187,000 |
136.08 |
|
|
185,000 |
111.1 |
|
|
163,000 |
138 |
|
|
159,000 |
136.078 |
|
|
157,000 |
124 |
|
|
152,000 |
151.9 |
|
|
151,000 |
97.5 |
|
|
151,000 |
112.1 |
|
|
Airbus A321-100[18] |
83,000 |
77.8 |
|
79,000 |
65.32 |
|
|
78,000 |
68.1 |
|
|
73,000 |
63.28 |
|
|
72,500 |
62.4 |
|
|
72,500 |
62.4 |
|
|
71,000 |
64.41 |
|
|
70,700 |
||
|
70,000 |
58.06 |
|
|
Airbus A320-100[18] |
68,000 |
66 |
|
68,000 |
54.9 |
|
|
68,000 |
||
|
67,000 |
||
|
66,000 |
54.66 |
|
|
65,000 |
57.61 |
|
|
65,000 |
REFERENCES: https://en.wikipedia.org/wiki/List_of_airliners_by_maximum_takeoff_weight
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Study 2: Is there any difference between ground speed and air speed?
It is important to understand the relationships of wind speed to ground speed and airspeed.
Wind Speed
For a reference point picked on the ground, the air moves relative to the reference point at the wind speed. Notice that the wind speed is a vector quantity and has both a magnitude and a direction. Direction is important. A 20 mph wind from the west is different from a 20 mph wind from the east. The wind has components in all three primary directions (north-south, east-west, and up-down). In this figure, we are considering only velocities along the aircraft's flight path. A positive velocity is defined to be in the direction of the aircraft's motion. We are neglecting cross winds, which occur perpendicular to the flight path but parallel to the ground, and updrafts and downdrafts, which occur perpendicular to the ground.
Ground Speed
For a reference point picked on the ground, the aircraft moves relative to the reference point at the ground speed. Ground speed is also a vector quantity so a comparison of the ground speed to the wind speed must be done according to rules for vector comparisons.
Airspeed
The important quantity in the generation of lift is the relative velocity between the object and the air, which is called the airspeed. Airspeed cannot be directly measured from a ground position, but must be computed from the ground speed and the wind speed. Airspeed is the vector difference between the ground speed and the wind speed.
Airspeed = Ground Speed - Wind Speed
On a perfectly still day, the airspeed is equal to the ground speed. But if the wind is blowing in the same direction that the aircraft is moving, the airspeed will be less than the ground speed.
Reference:
https://science.howstuffworks.com/transport/flight/modern/airspeed-vs-groundspeed.htm
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Study 3: Why is it not recommended to use aircraft engine power to move it on the ground at Airport?
Aircraft move using their own engine power all the time on the airport apron and taxiways under their own power to go towards runways and after landing taxi to their assigned gate.
The only time they use external assistance is to pushback from the gate. Large turbofan aircraft need help to reverse via a pushback tractor. The engines are turned on after the pushback is complete and the aircraft can move forward under It’s own power.
To be accurate, some aircraft can reverse using a variable pitch prop or thrust reversing on turbofans but generally reversing is done via pushback tractors. Blasting jet reversers blows debris In the crowded gate area creating foreign object damage hazard for adjacent aircraft, gate equipment or terminal waiting area glass windows.many aircrafts are capable of moving reverse using the reverse thrust, but this may cause damage to the terminal building and surroundings due to the resulting jet blast.Engine may also blow away sand and debris around and the suck them into it, causing damage to the engine.therefore a pushback tractor are used in airports to serve the purpose. This tractor lifts up the front wheels of the aircraft and help it move around the airport, from parking lot to the taxiways .
USE OF TAXIBOT TRACTOR
The TaxiBot is a semi-robotic towbarless aircraft tractor developed by the Lahav Division of Israel Aerospace Industries. The tractor can tow an aircraft from the terminal gate to the take-off point (taxi-out phase) and return it to the gate after landing (taxi-in phase). The TaxiBot eliminates the use of airplane engines during taxi-in and until immediately prior to take-off during taxi-out, significantly reducing aircraft fuel usage and the risk of foreign object damage. The TaxiBot is controlled by the pilot from the cockpit using the regular pilot controls[2] and has an 800-hp hybrid-electric engine.
- Pushback operation and procedures performed by TaxiBot identical to today
- Immediate taxiing after pushback eliminating bottlenecks in the gate area
- Taxiing with engines stopped. Engines start shortly before take-off with respect to required warm-up time
Unwanted consequences may follow due to unintentional movement of aircraft with engine running.
- i) Effectively a loss of control can happen, especially during high power engine running. Damage can occur to the aircraft itself, other aircraft nearby or to airside structures. There is a risk of injury to ground support personnel who may be in relatively close proximity to the aircraft.
iii) It is easier for truck driver to see the surroundings better than the pilot sitting in the cockpit with limited window. The pushback driver knows the airport better than the pilot.
- iv) It also saves fuel virgin Atlantic had proposed a new system in which pushback truck will move the aircraft all the way to runway to save fuel and reduce impact of environment. very loud.
- v) The plane engines are very loud, when more airplanes arrive the noise will be very unpleasant for the passengers and others near airport.3
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Study 4: How an aircraft is pushed to runway when its ready to take off?
Pushback
In aviation, pushback is an airport procedure during which an aircraft is pushed backwards away from its parking position, usually at an airport gate by external power.[1][2] Pushbacks are carried out by special, low-profile vehicles called pushback tractors or tugs.
Although many aircraft are capable of moving themselves backwards on the ground using reverse thrust (a procedure referred to as a powerback),[1] the resulting jet blast or prop wash might cause damage to the terminal building or equipment. Engines close to the ground may also blow sand and debris forward and then suck them into the engine, causing damage to the engine. A pushback is therefore the preferred method to move the aircraft away from the gate.
PROCEDURE
Pushbacks at busy aerodromes are usually subject to ground control clearance to facilitate ground movement on taxiways.[3][4] Once clearance is obtained, the pilot will communicate with the tractor driver (or a ground handler walking alongside the aircraft in some cases) to start the pushback. To communicate, a headset may be connected near the nose gear.
Since the pilots cannot see what is behind the aircraft, steering is done by the pushback tractor driver and not by the pilots. Depending on the aircraft type and airline procedure, a bypass pin may be temporarily installed into the nose gear to disconnect it from the aircraft's normal steering mechanism.
Once the pushback is completed, the towbar is disconnected, and any bypass pin removed. The ground handler will show the bypass pin to the pilots to make it clear that it has been removed.[3] The pushback is then complete, and the aircraft can taxi forward under its own power
REFERENCES
https://en.wikipedia.org/wiki/Pushback
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Study 5: Learn about take off power, tyre design, rolling resistance, tyre pressure, brake forces when landing.
The take off power can be understood as the power or the thrust from the engine to deliver the amount of thrust required to lift the airplane from ground level up to a certain desired height and speed.
Takeoff is the phase of flight in which an aerospace vehicle leaves the ground and becomes airborne. For aircraft traveling vertically, this is known as liftoff.
For aircraft that take off horizontally, this usually involves starting with a transition from moving along the ground on a runway. For balloons, helicopters and some specialized fixed-wing aircraft (VTOL aircraft such as the Harrier), no runway is needed.
On take-off, in order to position the aircraft to a safe height away from terrain and obstacles (i.e. a flight path of maximum height and minimum ground distance desired), the engine thrust is set to a high ‘take-off power’ setting (although this is not necessarily full power) and the aircraft attitude is pitched up to maintain a specific speed (usually in the region of V2 + 15kts). Once the ‘safe height’ is reached the engine thrust can therefore be reduced to a more appropriate (i.e. efficient) setting and the aircraft flight path can be changed to a more appropriate (i.e. efficient) flight path.
https://www.skybrary.aero/index.php/Take-off_and_Climb_-_A_Guide_for_Controllers#Take-off_and_Climb
https://www.faasafety.gov/gslac/ALC/course_content.aspx?cID=485&sID=795&preview=true
TYRE DESIGN
An aircraft tyre is designed to withstand extremely heavy loads while landing, take off, taxing, and parking. The number of wheels required for aircraft increases with the weight of the aircraft, as the weight of the aeroplane needs to be distributed more evenly.
Design and Construction of Aircraft tyre
Carcass plies are used to form the tire. They are sometimes called casing plies. An aircraft tyre is constructed for the purpose it serves.
- They support the weight of an aircraft while it is on the ground.
- It also provides the necessary traction for braking and stopping of an aeroplane.
- Tyre also helps to absorb the shock of landing and provide cushioning the roughness of takeoff, roll-out, and taxi operations.
Unlike an automobile or truck tyre, it does not have to carry a load for a long period of continuous operation. However, an aircraft tyre absorbs the high impact loads of landing, and also it’s operating at high speeds for a short time when required.
Two types of tires are used in aircraft applications — bias-ply tires and radial tires. Although both types of tires share some similarities in design, there are differences that need to be noted.
- Bias-ply tire construction
.
A cutaway of a typical bias-ply tire is shown in Figure 1. Bias-ply tires are popular choices for aircraft tires because of their durability and retreadability. The tire construction consists of the following components:
Tread: The tread is made of rubber mixed with other additives to obtain the desired level of toughness, durability, and resistance to wear. The tread pattern is designed to aircraft operational requirements, with the ribbed tread design used widely due to its good traction under varying runway conditions.
Sidewall: The sidewall is a protective layer of rubber that covers the outer casing ply. It extends from the tread edge to the bead area.
Tread Reinforcing Ply: One or more layers of fabric that strengthens and stabilizes the tread area for high-speed operation. It also serves as a reference for the buffing process when tires are retreaded.
Buff Line Cushion: The buff line cushion is made of rubber compound to enhance the adhesion between the tread reinforcing ply and the breakers or casing plies. It is of sufficient thickness to allow for the removal of the old tread when the tire is retreaded.
Breakers: Breakers are reinforcing plies of rubber-coated fabric placed under the buff line cushion to protect casing plies and strengthen and stabilize the tread area. They are considered an integral part of the casing construction.
Casing Plies: Alternate layers of rubber-coated fabric (running at opposite angles to one another) provide the strength of the tire.
Wire Beads: Hoops of high tensile strength steel wire that anchor the casing plies and provide a firm mounting surface on the wheel. The outer edge of the bead that fits against the wheel flange is called the bead heel. The inner bead edge is called the bead toe.
Apex Strip: A wedge of rubber affixed to the top of the bead bundle.
Flippers: Layers of rubberized fabric that help anchor the bead wires to the casing and improve the durability of the tire.
Ply Turnups: The casing plies are anchored by wrapping them around the wire beads, thus forming the ply turnups.
Chafer: A protective layer of rubber and/or fabric located between the casing plies and wheel to minimize chafing.
Chafer: A protective layer of rubber and/or fabric located between the casing plies and wheel to minimize chafing.
Liner: In tubeless tires, the liner is a layer of low permeability rubber that acts as a built-in tube and restricts gas from diffusing into the casing plies. In tube-type tires, a thinner liner is used to prevent tube chafing against the inside ply.
Radial-ply tire construction
A typical radial tire is illustrated in Figure 2. With their rigid belt, they provide increased landings and reduced rolling resistance. They have fewer components in their construction and are lighter than similarly sized bias ply tires. Components that differ from bias-ply construction as follows:
Overlay: A layer of reinforcing rubber coated fabric placed on top of the belts to aid in high speed operation.
Belt Plies: A composite structure that stiffens the tread area for increased landings. The belt plies increase the tire strength in the tread area.
Casing Plies: As in bias-ply tires, the casing plies are layers of rubber-coated fabric. However, unlike those in bias plies that run at opposite angles to one another, radial plies run radially from bead to bead.
Chippers: The chippers are layers of rubber-coated fabric applied at diagonal angles that improve the durability of the tire in the bead area
https://www.aviationhunt.com/aircraft-tyre-construction/
TYRE PRESSURE:
Aircraft tires generally operate at high pressures, up to 200 psi (14 bar; 1,400 kPa) for airliners, and even higher for business jets[citation needed]. The main landing gear on the Concorde was typically inflated to 232 psi (16.0 bar), whilst its tail bumper gear tires were as high as 294 psi (20.3 bar).The high pressure and weight load on the Concorde tyres were a significant factor in the loss of Air France Flight 4590.
Tests of airliner aircraft tires have shown that they are able to sustain pressures of maximum 800 psi (55 bar; 5,500 kPa) before bursting. During the tests the tires have to be filled with water, to prevent the test room being blown apart by the energy that would be released by a gas when the tire bursts.
Aircraft tires are usually inflated with nitrogen to minimize expansion and contraction from extreme changes in ambient temperature and pressure experienced during flight.Dry nitrogen expands at the same rate as other dry atmospheric gases (normal air is about 80% nitrogen), but common compressed air sources may contain moisture, which increases the expansion rate with temperature.
The requirement that an inert gas, such as nitrogen, be used instead of air for inflation of tires on certain transport category airplanes was prompted by at least three cases in which the oxygen in air-filled tires had combined with volatile gases given off by a severely overheated tire and exploded upon reaching autoignition temperature. The use of an inert gas for tire inflation eliminates the possibility of tire explosion.
Rolling resistance
In addition to the familiar forces like thrust, weight, lift, drag there is rolling resistance force Fr caused by friction between tyre and ground. When aircraft is towing or taxiing to be pushed into runway or during take off ,the rolling resistance force comes into paly.
The magnitude of force depends on many factors like surface of the road, roughness, dry or wet condition of the road , tyre pressure, tyre type, tyre temperature, threading etc
Rolling resistance force Fr= urr*m*g , where urr-coefficient of rolling resistance depends on types of environment conditions
m-mass of aircraft(gross)
g-gravitational force
Brake force during landing
Aircraft brakes stop a moving aircraft by converting its kinetic energy to heat energy by means of friction between rotating and stationary discs located in brake assemblies in the wheels. Brakes provide this critical stopping function during landings to enable airplanes to stop within the length of the runway. They also stop aircraft during rejected takeoff events, in which an attempted takeoff is canceled as the airplane is rolling down the runway before it lifts off from the ground due to engine failure, tire blowout, other system failure or direction from air traffic control.
Aircraft brakes also prevent motion of the aircraft when it is parked, limit its speed during taxiing and can even help steer the aircraft on the ground by applying different levels of braking force to the left- and right-side brakes.
Aircraft brakes work in conjunction with other brake mechanisms such as thrust reversers, air brakes and spoilers. Thrust reversers are surfaces that are deployed into the path of the jet blast from the engines to redirect propulsive thrust in a direction that opposes the motion of the aircraft. Air brakes and spoilers are flight control surfaces that create additional aerodynamic drag when deployed into the path of air flowing around the aircraft.
How aircraft brakes work
The most common type of brake used on aircraft is the disc brake. Disc brakes function by exploiting friction between rotating and stationary discs inside the brake.
Upon receiving a command signal to brake — from the pilot depressing a foot pedal or from the autobrake system — actuators in the brake move a piston to squeeze the discs together, generating a frictional force that slows the rotation of the wheel. The friction between the discs generates heat as the aircraft’s kinetic energy is converted to heat energy. In this function, the brakes act as a heat sink, absorbing tremendous amounts of heat as the aircraft sheds kinetic energy. During RTO stops, the temperature of carbon disc brakes can exceed 1,800° C.
The discs are mounted on a carrier assembly consisting of a torque tube, which resists and transmits brake torque to the landing gear structure. Sandwiched together between the carrier assembly housing and a backing plate, the discs are arranged in an alternating pattern of rotors and stators. Notch and groove geometry around the circumference of each rotor fits into corresponding geometry in the wheel, keying the rotors to the wheel so that they rotate with it. The stators are keyed to the torque tube and are thus held stationary since the torque tube is connected to the axle and landing gear structure.
Cylindrical spaces within the carrier assembly hold actuator pistons. Braking occurs as piston force squeezes the discs together.
To illustrate how much energy this is, consider an Airbus A380 — the world’s biggest passenger airplane — performing an RTO at V1. The maximum take-off weight of an A380 is 575,000 kg (1,267,658 lb) and its maximum V1 is around 170 knots (about 195 mph or 87 m/s). A rough estimate for the maximum energy that the A380’s 16 brakes need to dissipate during RTO can be obtained by calculating the kinetic energy of the aircraft (neglecting the effects of thrust reversers, air brakes, tailwinds, headwinds and runway slope).
Since kinetic energy (KE) is a function of mass (m) and velocity (v) according to the equation:
KE = ½mv2
The kinetic energy of the A380 during RTO is calculated as follows:
KE = 0.5 * 575,000 kg * (87.4556 m/s)2 = 2.2 x 109 J = 2.2 GJ
2.2 GJ (gigajoules) is about the amount of energy an average cloud-to-ground lightning strike dissipates. It is also enough energy to power an 8 W LED light bulb (with light output equivalent to a 60 W light bulb) continuously for 8 years and 10 months.
To generate the necessary frictional forces and to handle this much energy within the length of a runway, large commercial transport aircraft typically require multiple discs per brake assembly and brakes on most, if not all, of their wheels.
For example, an A380 has 22 wheels distributed on five landing gear legs to support its massive weight: two nose wheels on a leg beneath the nose of the aircraft, eight wing wheels split between two legs that fold out from under the fuselage to support the left and right wings, and 12 body wheels split between two inboard landing gear legs under the fuselage. Sixteen of these wheels have brakes (four aft body wheels and the nose wheels are not braked).
Spoilers
These are the called the spoilers as they literally spoil the airflow over the wing. This dumps any remaining lift the wings are generating, allowing the wheels to take all the weight and achieve maximum efficiency from the brakes.
Reverse thrust
The final part of the braking process comes from reverse thrust. Just after we have touched down, we pull two levers on top of the thrust levers to engage the reverse thrust, a sort of “reverse gear” for jet engines.
This causes blockers inside the engine to deploy and a door in the side of the engine to slide backward. The air which normally leaves the engine out the back is deflected forward by the blockers and out through the door.
REFERENCES:
https://thepointsguy.com/guide/how-do-aircraft-brakes-work/
https://insights.globalspec.com/article/12903/how-do-aircraft-brakes-work
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PART-B
Study 6:
A) With necessary assumptions, calculate the force and power required to push / pull an aircraft by a towing vehicle.
Various forces acting on the aircraft towing tractor,
- Rolling resistance
- Aerodynamic force
- Hill climbing
ROLLING RESISTANCE FORCE:
Rolling resistance, sometimes called rolling friction or rolling drag, is the force resisting the motion when a body (such as a ball, tire, or wheel) rolls on a surface. It is mainly caused by non elastic effects; that is, not all the energy needed for deformation (or movement) of the wheel roadbed, etc
Formula for rolling resistance force are given below.
µ varies with speed m- mass and g-gravity
AERODYNAMIC DRAG FORCE:
The force on an object that resists its motion through a fluid is called drag. When the fluid is a gas like air, it is called aerodynamic drag or air resistance
Where.
ρ- air density kg/m^3
A-frontal area of vehicle
Cd- drag coefficient
v-velocity m/s
HILL CLIMBING FORCE :
The force needed to drive the vehicle over the slope. It is simply the component of the vehicle weight that acts along the slope.
Given by,
CALCULATION OF PROPULSION POWER
Rolling resistance force
Weight of the Aircraft (Boeing 737) =79000 Kg [payload]
Weight of the towing tractor 50000 kg
Rolling resistance coefficient of towing vehicle =(Urr) 0.001 (Assume)
Rolling resistance force of tow tractor Urr (m.g) =0.001( (50000+79000)*9.81
The total Rolling Resistance Force Frr =1.26 KN
Air drag force
The velocity while Towing = 20 KMPH = 5.56 m/s (Assume)
Density of Air medium (rho) = 1.225 (Assume)
The Frontal area of the towing truck =20 m^2 (Assume)
The coefficient of Drag of airplane = 0.03 (Assume)
The coefficient of Drag of tow truck = 0.6 (Assume)
Air drag force = 0.5 rho A.V^2 .cd= 0.5* 1.225* 20 *5.56 ^2*( 0.03+0.6)= 238N
The Air Drag Force Acting = 0.238 KN
Therefore the total force that the motor needs to overcome= Rolling resistance of the aircraft +Drag force acting on the forces a=1.26 +0.238
The Total Force that the motor needs to overcome in order to Push/pull the Aircraft Fte= 1.503 KN
The Power Required:
The power required by the motor is given by the velocity with which the towing operation takes
The average speed of Push/Pull= 20 kmph =5.5 m/s
Power required by the motor = Total forces * velocity = 1.503 KN * 5.5
Power required by the motor 8.26 Kw
The torque output of the towing tractor can also be calculated by the below steps.
Fte=T.G/r
where.
Fte-The Total Tractive force (Rolling resistance force Air drag force)
T-Torque output
r-Radius of tire
G-Gear ratio
For a Heavy Duty Towing tractor we assume,
G-11 (For delivering high torque)
r-25 inches = 0.635 m
T=Fter/G=1503 *0.635/11
The Torque required to Push/pull for the above stated condition 86.83 KNm
B) Develop the model for the calculated force and power using Simulink.
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Study 7:
- Design an electric powertrain with type of motor, it’s power rating, and energy requirement to fulfill aircraft towing application in Simulink. Estimate the duty cycle range to control the aircraft speed from zero to highest. Make all required assumptions. Prepare a table of assumed parameters. Draw a block diagram of powertrain.
- Also, Design the parameters in excel sheet.
Solution:
- To design an electric power train for aircraft towing application
Steps to follow for obtaining the design
Determining the energy required to be delivered to the power train
↓
Motor selection based on the propulsion power requirement
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Power converters and controllers to convert and control power
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Speed control of motor using various switching techniques with duty cycle
ASSUMED PARAMETERS
|
S.NO |
PARAMETERS |
|
1. Weight of the aircraft 2. Weight of the towing tractor 3. Rolling resistance coefficient of towing tractor 4. Rolling resistance of the aircraft 5. The velocity of the aircraft while towing 6. Density of the air medium (rho) 7. The frontal area of the tractor 8. The coefficient of drag 9. Towing tractor gear ration ‘ G’ 10. Towing Tractor tyre radius “ r ” 11. Time of towing for one cycle 12. The battery armature voltage 13. The battery armature current 14. The motor terminal voltage 15. Power converter used 16. Duty ratio for achieving full power |
79000 kg 50000 kg 0.001 0.001 20 km/h 1.225 20 m^2 0.63 11 25 inch 0.5 Hr 350V 350A 400V Rated DC DC boost converter 70% |
Operational time of tractor 30 minutes
30 min=0.5 hour
∴Energy(Kwh)=Power(KW)* Time(h)= 8.26*0.5
Energy = 4.13 kWh
Hence, The battery must be able to store and deliver higher than 4.13 kWh of energy Throughout the run in order for the motor to generate rated torque
Motor selection:
Here we have selected a Brushless DC motor having a power rating 10KW.
The motor is 92% efficient at voltages between 24 to 72 VDC. Continuous current of 125 amps AC (180 Amps DC into the motor control). This is a 3-phase, Y-connected Permanent Magnet Synchronous Motor with an axial air gap and Sine/Cosine Speed Sensor. It has two stators with a rotor in the center.
BRUSHLESS DESIGN = 0 maintenance.
POWER: Output Power of 10 kW Continuous, 24 kW Peak
Specifications
- 4 pole motor (8 magnets).
- Phase to Phase winding resistance is 0.065 Ohms with 20 turns per phase.
- Maximum recommended rotor speed: 5000 RPM
- Voltage: 0 to 72 VDC input to the control
- Torque constant of 0.12 Nm/A
- The Inductance Phase to Phase is 0.05 Milli-Henry
- Armature Inertia: 45 Kg Cm Squared
- Current: 125 Amps AC continuous (180 Amps DC into the motor control)
- Peak current: 420 Amps AC for 1 minute (600 Amps DC into the motor control)
- Weight: 35 pounds
- Peak Stall Torque: 60 ft lb.
- Cooling: Open Frame, Fan Cooled motor
Speed control and duty cycle
The amount of power can be controlled by changing the duty cycle of the switching converter.
Considering the losses we assume 70% of the duty cycle to deliver rated power of motor.
Motor terminal voltage = armature voltage*duty cycle = 400*0.7 = 280V
Hence AT 70% duty cycle the motor provides Rated power at 280V
Thus By varying the duty cycle 0-70% the speed of the vehicle can be controlled
Block diagram:
REFERENCES