Brushless car alternator. (Horse Power) of a car alternator converted to a motor.

Brushless car alternator 5 kva, 15 kva to 120 kva Stamford alternators Select category Select category An alternator (preferably salvaged from a car) A scootеr or kickbike frame; A BLDC motor controller; A throttle; A battery (preferably lithium-ion) A sprocket and chain; Connectors and wires; Tools for assembly (wrenches, pliers, etc. 12V 1 day ago · Alternator Temp Sensor: MC-TS-B: Battery Temp Sensor (1) Balmar’s 96-Series 48V Alternators are designed to be used with the MC-620 Multi-Stage Regulator. This electrical connection arrangement eliminates any electrolysis at the Nov 18, 2024 · Even when the car starters are tested outside the car with any load and without the solenoid engaged (as the solenoid also pulls 35A suddenly and settles to 18-20Amps I have seen) it pulls above 60Amps. DIY Alternator to brushless motor Shop for the best Alternator for your 2005 Lincoln Town Car, and you can place your order online and pick up for free at your local O'Reilly Auto Parts. DIY E-Bike Out of Car Alternator: This alternator might seems like a regular one but in our previous project we have converted it into a powerful brushless motor the link to is given below. Brushless alternators are two alternators in one, with two rotors and two stators. In this video, a small alternator is tested to see how The 33SI is a heavy duty brushless alternator that provides more output and service life for today’s diesel powered vehicles with large electrical load requirements. ,Ltd Brushless Alternator Type. Jfz2716D Weichai Truck Alternator HOWO US$ 30-50 / Piece. Converting a car alternator to a brushless DC motor is a rewarding project that can unlock a world of possibilities for DIY enthusiasts and engineers. Brushless technology allows the transfer of electrical current between the rotor and stator in the rear portion to excite the main alternator. Sonawane 1 Assistant Professor; 2 ME (EPS) Student Department of Electrical Engg. An alternator is an essential component in any automobile, responsible for converting mechanical energy from the engine into electrical energy to power various systems. It consists of two main components: a stator and a rotor. The working of an AC car is dependent upon the alternator which is found to be quite simple as well as less complex. Fan Type Apr 8, 2019 · Here we call Alternator Motors Hybrid Brushless Motors because all power drive current to this motor is brushless; (Horse Power) of a car alternator converted to a motor. A BL alternator does not have See more Automobile alternators typically have brushes to power the field, and produce 3-phase AC power, so they are basically brushed type 3-phase alternators. Now The Rapid Power Proprietary Brushless components integrate into a range of commonly used OE brushed alternators. 8 (USD Billion) in 2023. Nov 22, 2019 · An alternator converted to a hybrid brushless motor provides a low-cost alternative to brushless motors (BLDC) because alternators are mass-produced, far in excess the - old car alternator - servo tester - Brushless ESC speed contorler - 12V Battery - 5V Power supply (old PC supply or some DC step-down) Step 2: Disassembling. Fan Type: Jun 27, 2022 · A car alternator is an electrical generator that converts mechanical energy into electrical energy to keep a car’s battery charged and to power the car’s electrical systems. Voltage. Ready to Ship $52. Multigroove pulley. 12V/60A AC Auto Car Alternator 12v ISUZU Alternator Ac 24v Denso 021080-0470 Original Sc460-171200461 Engine Alternator 60A EXEN Aug 22, 2022 · Brushless Generators; Brushless generators are characterized by their stability, low noise level, and long life. CONNECT with O'Reilly Aug 3, 2022 · As Nikola Tesla proved in 1887, alternating current becomes more attractive as it generates higher voltage more efficiently, something necessary in contemporary automobiles. Brushless Alternator Diagram Schematic And Image 02. Oct 10, 2017 · BRUSHLESS, 24V, 110-140A BRUSHLESS, 24V, 90-110A BRUSHLESS, 24V, 75A BRUSHLESS, 24V, 85-90A With Brush type Brushless type (kg) BRUSHLESS 24V, 140A ALTERNATOR for Diesel Engine Series Table 10 25 20 15 BRUSHLESS, 24V, 50-60A BRUSHLESS, 24V, 40-60A BRUSHLESS, 24V, 50-60A 20 40 60 80 W/BRUSH, 24V, 25-35A Oct 2, 2019 · The brushless alternator have error-operated AVR and excitation system. Performance Output: 12 Volts 110 & 135 Amps 24 Volts 75 & 100 Amps: Maximum Speed: 10,000 RPM Continuous 12,000 RPM Intermittent: Rotation: Clockwise Shop for the best Alternator for your 2000 Lincoln Town Car, and you can place your order online and pick up for free at your local O'Reilly Auto Parts. Though I might run it only for 3-4seconds, from your explanation the initial current draw by the starter will exceed 80A and may make the Shop for the best Alternator for your 2002 Lincoln Town Car, and you can place your order online and pick up for free at your local O'Reilly Auto Parts. Shipping per piece: $17. asesupply. Also, you don't need to replace the brushes, which is very economical and convenient. The supply voltage would probably need to be at least 24v, but ideally a lot more, like 48 - 96V. The 36SI™ is a durable brushless model available in an output rating up to 170 Amps at 12 volts or up to 105 Amps at 24 Volts. also what Shop for the best Alternator for your 1999 Lincoln Town Car, and you can place your order online and pick up for free at your local O'Reilly Auto Parts. 12V. Video. Sunday CLOSED Sep 20, 2022 · Converting Car Alternator Into A Permanent Magnet Brushless Motor Output Bookreader Item Preview converting-car-alternator-into-a-permanent-magnet-brushless-motor Identifier-ark ark:/13960/s2f6m0qhkj9 Ocr Shop for the best Alternator for your 1996 Lincoln Town Car, and you can place your order online and pick up for free at your local O'Reilly Auto Parts. China Brushless Alternator wholesale - Select 2025 high quality Brushless Alternator products in best price from certified Chinese Diesel Generator manufacturers, Brushless Dc Motor suppliers, wholesalers and factory on Made-in-China. 42%. But car batteries can't use AC power since they 12V Car Battery Alternator Charge Tester. 45%. Cooling Method: Alternator Remanufactured; 175 Amp; Limousine; High Output Replacement. It is Best price Angel alternator 8 kw to 50 kw Carbon Type Stamford brushless alternators importer in Pakistan. Brushless Alternator Price - Select 2025 high quality Brushless Alternator Price products in best price from certified Chinese Brushless Synchronous Alternator manufacturers, Natural Gas Generator suppliers, wholesalers and factory on Made-in-China. 00. The main alternator is the larger of the two sections, and the exciter is the smaller. The proper voltage forces more current into the battery bringing it to alternators, including the automotive type, generate 3-phase power. • Voltage regulation is 5 days ago · Svd 27060-11281 Car Parts Generator Alternator 27060-17090 Fortoyota, Find Details and Price about 27060-11281 Alternator from Svd 27060-11281 Car Parts Generator Alternator 27060-17090 Fortoyota - Guangzhou SVD Auto Parts Co. Performs above 40 °C. A properly grounded alternator is essential for a reliable and efficient car. I understand in principle how an ESC works, but I don't understand how this Output of Brushless ESC for Shop for the best Alternator for your 2001 Lincoln Town Car, and you can place your order online and pick up for free at your local O'Reilly Auto Parts. I'm debating between creating a controller entirely from scratch that combines the brushless driver, and the rotor field current High Power 48V (56V) 50A-250A 2kw-12kw Car Alternator, Find Details and Price about Car Alternator Alternator from High Power 48V (56V) 50A-250A 2kw-12kw Car Alternator - Nanjing JPG Bearing & Equipment Co. 901. Claw-pole Type. Fan Mar 19, 2024 · However, the alternator in a hybrid car serves a different purpose compared to traditional vehicles. 20pcs Press Fit Diode ZQ35A ZQ50A For Brushless Alternator Generator Parts 10. CONNECT with O'Reilly Shop for the best Alternator for your 1994 Lincoln Town Car, and you can place your order online and pick up for free at your local O'Reilly Auto Parts. repco-au. Vehicle Fitment Guide. The alternator is rated at 14v and 70A, so ~1kw. Electromagnetic Vibratory. With a car alternator this is done by controlling the voltage/current to the excitation winding. 210 7711497423 A004TJ0881 A4TJ0881 DRA1199 UD11048A FOR RENAULT 24V 80A(100A) An alternator’s excitation system for a typical modern alternator would have the following features: • Rotating field: excitation rotor, rectifier unit and main rotor turning within the main stator. The larger of the two sections is the main alternator and the smaller one is the exciter. , Ltd. 21. [20] With the advancement in semiconductor technology, brushless alternators are The humble automotive alternator hides an interesting secret. Fan Type Oct 26, 2021 · In a simple explanation, an alternator can be turned into a 3 phase AC motor. Favorites. In a conventional alternator, the magnet is mounted on a rotating armature with brushes that contact the field coil to create the electric current. Alternators pull air from the back to the front in order to cool the internal electronics. The Delco Remy 36SI brushless alternator design dramatically increases both the durability and the life of the alternator. com Car Alternator (1,823) More; Product Features. By following these steps and addressing potential issues, you can ensure your alternator is working correctly, keeping your battery charged and your vehicle running smoothly. Pulley Belt Type: Serpentine. 8L (OEM: 3701100K0000) - Feb 11, 2016 · I knew that a car alternator was really just a 3-phase synchronous motor with a 3-phase rectifier to give DC out. Find out more in this article. 12V Car Battery Tester Alternator Battery Tester with 6 LED Digital Display - 12V led digital Brand New . 4 (USD Billion) by 2032. Exen. i have an idea to convert this car "They produce a high output alternators and some of the finest brushless alternators available today. 50 Pieces (MOQ) Our Alternator offers exceptional quality and Brushless, Permanent Magnet Generators, also known by the trade name "NoBrush” or PMGs are converters constructed with a 60 or 50 Hz induction drive motor, mounted on a common shaft with a permanent magnet alternator. 1 Year Limited Warranty. A so-called brushless DC motor is simply an AC motor with a bundle of electronics that turns a DC supply Delco Remy 36SI™ High Output Brushless Alternator. Chat now. An automotive alternator can be converted into a powerful hybrid brushless motor, and can exceed the performance of conventional brushless motors (BLDC). Our brushless alternators result in Sep 13, 2017 · 5. Brushless Alternator With Claw Pole Rotor Diagram Schematic And Image 03. Mon – Sat: 9:00am–18:00pm. The stator generates a magnetic field, while the rotor rotates within it, inducing electrical current in May 1, 2023 · By following these steps, you can easily modify a car alternator into a brushless generator and create a perpetual power generator that generates 220 volts and 10,000 watts of power. The brushes create friction and wear out over time, which can cause the alternator to become less efficient. com Brushless Free Energy Car Spare Parts Alternator Ah2210300ab 104210-2420 for Land Rover US$ 45-60 Shop for the best Alternator for your 2015 Toyota Corolla, and you can place your order online and pick up for free at your local O'Reilly Auto Parts. Answers to Your Most Common Questions. , page1. Car alternators; Diesel-electric alternators; Marine alternators; A Brushless alternator, on the other hand, is more suitable for Apr 8, 2019 · Alternator conversion manual shows how to convert a car alternator into a high-power motor as a low-cost alternative to a high-power brushless motor. M. 8L (OEM: 3701100K0000), Find Details and Price about Auto Parts Car Parts from Auto Parts Car Motor Alternator for Jfz1969 1. Plug Clock Alternator Remanufactured; 130 Amp; Originally Equipped. Pure Copper Coils; This China alternator catalog of 12V 120A Car Alternator for Vale Lester Sg12s077 Sg12s051 Auto Parts, 12V 220A Car Alternator for Vale Lra03987 Fg23s068 Auto Parts provided by China manufacturer - Ningbo Hi-Tech Altering Motor Co. 9 /5 · 15 reviews · "fast delivery" Contact Supplier. Removing the brushes from an alternator eliminates commonly occurring brush/brush spring/slipring failure The DelStar Series, heavy duty brushless alternators are an integral charging system of an innovative design. Find a distributor near you! Distributor Address Contact Website; ASE Supply. Brushless technology has enabled them. An alternator easily generates more than a 100V, without regulation. Voltage Adjuster Type. The exciter has stationary field coils Nov 16, 2008 · So last night I recieved a RC brushless motor ESC in the mail, and got a alternator turning. Alternator Market Research Report: By Voltage (12V, 24V, 48V, Over 48V (60V, 72V, 140V)), By Type (Brushed Alternator, Brushless From brushless designs with fewer moving parts to remote sense to improve battery charge time, Delco Remy technology is second to none. Plug Clock  · สอนทำไดชาร์จเก่าให้เป็นมอเตอร์บัสเลส | Convert Car Alternator to Brushless motor Generator 12v การติดแม่เหล็กให้ทนแน่นไม่หลุดง่าย Jan 27, 2024 · We are curious to see if a car alternator can be a powerful brushless motor and for that we are going to find out by converting our bicycle into an electric one. Cost Factors That Influence Brushless Alternator Price. Car Alternators Make Great Electric Motors Here S How Hackaday. ₦ 50,000. KIA PRIDE KK13718300 KK13718300B KK333-18-300 Suitable Car Alternator Auto 12v Pride - K4313 Xs3301041 2 Claw-pole Type SHB-096D The alternator is connected to the battery via a continuous cable that exits the alternator via an IP68 gland. Product Types. Get deals on automotive parts, truck parts and more. It is found containing two different types of windings like a stator which includes a stationary outside winding and a rotor 90A 100% New Car Alternator 24v Brushless Alternator M263 For E320D 34368038 A004TU3599 A4TU3599. Since a brushless alternator has no brushes, it has fewer moving parts and is less prone to Aug 6, 2024 · Passenger Car Alternator Market Size was estimated at 17. A 3-phase brushless alternator may have 4 or DIY- Convert old Car Alternator to Brushless motor / Generator - Amazing ideai took it from my friend, his name is Phuc. The voltage has to change for the AVR to register the deviation from normal and to then adjust the excitation for correction. Cadillac escalade 2014 년도 차량 주행중 갑자기 파워가 안들어옵니다 ?Car alternator ic voltage regulator wiring diagram Alternator wiring hitachi schema alternatore regulator charging voltage briggs brushless diode hp elettrico schematron spia yanmar lampe carica batterie alternateurSimple alternator wiring diagram. While traditional car alternators have served their purpose With a brushless alternator, there are no issues of dust hanging up brushes and causing early failure. History; Mar 12, 2022 · I saw a video on the net, titled "How to Convert Car Alternator To Brushless Motor / No ESC With Mosfet Driver". Add to cart. With the increased demand for extended service life products, Delco Remy’s Brushless Alternators are quickly becoming the standard of the industry. Shop for the best Alternator for your 2003 Lincoln Town Car, and you can place your order online and pick up for free at your local O'Reilly Auto Parts. Car Bras; Car Covers; Cargo Carriers & Roof Racks Brushless: No: Buyer's Guide. DAH KEE offers brush type and brushless type alternators to meet the needs of each vehicle and equipment manufacturer for construction and agricultural markets. • Brushless: The field is generated by the exciter, rectified to dc and induced into the main rotor winding. The Long Haul has been designed with fleet maintenance in mind. 33SI™ Brushless Type Alternator. Smaller brushless alternators may appear to be a single unit, but the two parts are easily distinguishable on larger models. Smaller brushless alternators may appear to be a single unit, but the two parts Arrow Board, Transit Bus-Motor Coach, Construction-Mining, Emergency Vehicle, Ambulance-Fire truck, Commercial Marine, Railroad, Electrodyne® is the leader in brushless Alternator design and craftsmanship. The suddenness of the initial volt is such that the response from the error-operated system cannot come until the dip is in the second slower stage. When buying a car alternator, consider these vital features: Electrical Aug 10, 2018 · BRUSHLESS ALTERNATOR FOR AUTOMOTIVE APPLICATIONS 1 Prof. Also, video! May 20, 2023 · I got an alternator from a friend, and turned it into a brushless motor (removed the rotor winding, printed a new centre for it with my 3D printer and fitted 12 magnets). 2 Year LIMITED WARRANTY. Brushless Alternator Type: Magnetizing Type. . Fan Type: The Mastervolt Alpha alternator is specifically designed for powerful charging, even with a low engine rpm. Until 1966, alternators used brushes with rotating field. Stay tuned for that project. 1 / 6. Min Order: 10 pieces. KSh 8,948. Here’s why: Brushless alternators have fewer moving parts, which means less wear on the alternator. It requires explicit maintenance to offer higher durability and longevity. Shop your parts faster, select your vehicle. Georator PMGs utilize a single, all metal housing to enclose both motor and generator components. An alternator, as part of a car’s electrical system, is responsible for keeping the battery charged and powering various electrical Feb 9, 2024 · Designed to deliver higher output at lower RPM and with a corrosion resistant rectifier and rotor, DENSO’s 24-volt heavy duty brushless alternator, which features high load rated front and rear bearings to provide 3 days ago · Brushless AC Alternator JFWZ27 1000W 28V for Diesel Engine, Find Details and Price about Alternators Alternator from Brushless AC Alternator JFWZ27 1000W 28V for Diesel Engine - Liaocheng ELN Electromechanics Sep 21, 2024 · Final Thoughts: A Smooth Ride Ahead. Smaller brushless alternators may look like one unit but the two parts are readily Delco Remy 40SI™ High Output Brushless Alternator. Limited Lifetime Warranty. 4. Available Models: A brushless generator uses rotors to generate electricity instead of traditional carbon brushes. Cooling Method: Alternator Remanufactured; 130 Amp; Includes Pulley And Regulator; With Engine Cooler High Output Alternator 48V 300A AA125-521711-522; ALMOTT ALTERNATORS & SPARE PARTS, ALTERNATORS 48 VOLT; Voltage: 48VOutput: 300AEfficiency: more than 85%Mounting: Cradle Style (Saddle Brushless alternators eliminate 13 moving parts by doing away with the slip rings and brushes. From 12 volt applications such as utility & work trucks, fire trucks, and long haul trucks with auxiliary power units to 24 volt applications like wheel loaders, graders and Buy Alternator - New 200 A - BSH AL9962SB online from NAPA Auto Parts Stores. You need a suitable controller to do that. 24V. Not only is it an affordable way to generate Oct 4, 2024 · A brushless alternator is composed of two alternators built end-to-end on one shaft. The 33SI is offered in 12 Jan 3, 2025 · Auto Parts Car Motor Alternator for Jfz1969 1. Buy Sample Min Order. Brushless Design: No. Caution: The MC-620 Regulator requires a 12V input, consuming 3 days ago · 24V/90A AC Auto Car Alternator for 2610987 R215, Find Details and Price about 24V Alternator 90A Alternator from 24V/90A AC Auto Car Alternator for 2610987 R215 - Jiangsu Excellens Auto Electric Appliance Co. ) Step 2: Convert the Alternator to a BLDC Motor. A three-phase AC alternator will not have any diodes in it. Q: How often should I check my Sep 20, 2013 · I would speculate that in order to make good use of an alternator as a motor (BLDC), you would need to add sensors to it and use a BLDC sensored controller. The Apr 15, 2024 · I am building a hybrid bike, I want it to work similarly to a diesel-electric locomotive, if I can find a 1000w 48 volt brushless dc motor and use a 1000w max dc generator that outputs 48 volts, the generator would be spun using a petrol engine, to vary the speed of the electric motor, would I be able to just vary the rpm of the petrol engine turning the generator. High efficiency translates to less engine horsepower Alternators manufacturer. Shembekar; 2Miss P. Our famous Final Thoughts: From Automotive Part to Powerful Motor. Links. Brushless Alternators Wiring Instructions. Fan 12V Car Battery Alternator Tester Test Battery Condition Alternator Charging LED indication. The Passenger Car Alternator Market Industry is expected to grow from 18. Smaller brushless alternators may look like one unit but the two parts are readily Aug 8, 2024 · Understanding the Basics of Alternators. com: 5. This is the configuration used in automotive alternators. Contact Now Request Sample Inquiry Basket. KSh 5,190. you can get them off ebay for a good price, Just look for something suited to an ebike or similar sized motor. Head Oct 14, 2024 · Circuit diagram of alternator regulator. A car alternator changed over to a brushless hybrid Shop for the best Alternator for your 1997 Lincoln Town Car, and you can place your order online and pick up for free at your local O'Reilly Auto Parts. S. 52(USD Billion) in 2024 to 25. Transport Package Brushless Alternator Type: Claw-pole Type. A brushless is more efficient. Its efficiency rating is best-in-class. The 40SI™ is a durable brushless model available in output ranging from 240 to 320 Amps. 7710 NE 17th Ave Portland, OR 97211: Phone: (503) 288-0100: www. Electronical. 258 Mohr Junction, Willside, 04643 Idaho. Pulley Belt Type: Alternator Remanufactured; 200 Amp; Limousine Or Police; High Output Replacement. i was thinking that the wound rotor could have controlable voltage, say 100%, 75%, 50% and 25% of system voltage to give some sort of rudimentry gearing. 7 yrs CN Supplier . If the output is DC, it will probably have 6 diodes to convert the output from the main alternator to DC. This Brushless car alternators have revolutionised the automotive industry by offering improved efficiency, reduced maintenance, compact size, and enhanced control. Fan Type: Shop for the best Alternator for your 2004 Lincoln Town Car, and you can place your order online and pick up for free at your local O'Reilly Auto Parts. Smaller brushless alternators may look like one unit but the two parts are readily identifiable on the large versions. By understanding the fundamental principles and following these detailed instructions, you can transform a seemingly ordinary automotive part into a Main alternator and; Excitor alternator; A Brushless alternator is made up of two alternators that are built end-to-end on a single shaft. Add to Aug 12, 2008 · hi, i've got a spare alternator from my VW TDI, and am considering converting it to a hybrid brushless motor (powered rotor) for an E bike. The 12/130 and 24/75 models are also available with a multigroove pulley. OK Oct 1, 2023 · Passenger vehicles typically have a brushed alternator, and car alternator output amps typically range between 40 amps to 120 amps. is concern not only on small cars, but they are used also in agricultural engineering, structural engineering, stationary generators etc. KSh 1,444. Jun 6, 2020 · Types of Alternator based on its use. Alternator Mazda Cx9. a Castle Sidewinder 3 1/10th scale waterproof sport brushless ESC/Motor). ABOUT NAPA. 5 days ago · 12V 130A Car Alternator for Denso 104211-9070 Lra04405 Auto Parts, Find Details and Price about Silent Generator Generator from 12V 130A Car Alternator for Denso 104211-9070 Lra04405 Auto Parts - Ningbo Hi-Tech Oct 25, 2021 · Your garden variety automotive alternator is ripe for repurposing as is, but with a little modification, it can actually be used as a surprisingly powerful brushless motor. Cooling Method: Air. Without brushes, there are 13 fewer moving parts, eliminating components that wear A Brushless alternator is made up of two alternators that are built end-to-end on a single shaft. Cooling Method: Alternator Remanufactured; 130 Amp; Includes Pulley And Regulator; With Engine Cooler Shop for the best Alternator for your 1995 Lincoln Town Car, and you can place your order online and pick up for free at your local O'Reilly Auto Parts. Brand. 8 kva, 12. " Electric Motor Service | Read More. KSh 2,637. Pulley Belt Type: Alternator Remanufactured; 135 Amp; Interchangeable With Part Number: GLV-9011-RM. Safety Information. Feb 12, 2023 · 40si High Output Brushless Alternator Delco Remy. offers from. If you want to investigate this further 3-phase brushless motors can and are frequently used in this application (see combined starter /generator applications for automotive apps etc), but obviously those without integral controllers. Product Reviews. A larger vehicle may need a more For large fleets, a brushless alternator can be an ideal choice. The end result is longer life. A brushless alternator is composed of two alternators built end-to-end on one shaft. I'm debating between creating a controller entirely from scratch that combines the brushless driver, and the rotor field current regulator, or a controller that outputs a PWM signal for any brushless ESC and also controls the rotor current. Delco Remy 55SI™ High Output Heavy Duty Brushless Alternator. A. This is Bosch alternator from 24V Auto Alternator 629003203 6290104 0110894 01182165 A011-154-96-02 434035 3033180 Fits Daf 95 Mercedes Atego Man NM NL Alternator For Kia LRA02150, LRA2150, AF185381, AF185452 NEW HNROCK 12V 210A ALTERNATOR 23100-0009R 231000009R 575. They are produced Jul 4, 2008 · So last night I recieved a RC brushless motor ESC in the mail, and got a alternator turning. The compact, heavy duty construction provides efficiency and increased service life expected to match the longer The alternator handles the crucial electrical components in your vehicle and making sure it is running efficiently could save you from major car trouble. Looking Dec 30, 2019 · Several alternator types have cases drilled straight through for rectifier mount screws, longer screws or bolts/nuts make for easy mounting of that second Rectifier. hmcgjc qmzpz gyrnovsr vssu ylvav wsit lvng wkaschb iokfwu zhf