Electric Motorbike Inc.
Home of the Lectra electric motorcycle
The Lectra Electric Motorcycle - World Record Holder
|Manufacturer||EMB Incorporated (until Dec. 1999)|
|Warranty||1 Year Limited|
|Top Speed||45 mph (51 mph option)|
|Range||upto 35 miles, see simulator|
|Recharge Time||4.2 hours (20% to 95%)|
|VR24||Electric, 24 vdc
2-phase brushless design, Air Cooled
|Torque||8 ft-lbs peak (40 ft-lb after reduction)
5:1 Helical Gearset, Internal to Motor
|Optima D750S (x4)||Valve-regulated lead-acid
Absorbed Glass Mat (AGM) type
Non-spill, Maintenance free
|Life Cycle||300-350 deep discharge(100% D.O.D.)|
|104 amp-hour, 24 volt VRLA/AGM advanced battery pack|
|VR24TM drive system with integral helical gear speed reduction|
|Fully automatic on-board charger|
|Electric, power-assisted regenerating rear brake with anti-lock features|
|Hydraulic fork with aluminum triple clamps|
|Twin coil-over-shock, adjustable rear suspension|
|Full floating hydraulic caliper front disk brake|
|Cast aluminum alloy helical style wheels|
|Dunlop performance tires|
|Electronic twist grip "smart" throttle|
|Safety neutral mode with "Power" select|
|Chrome foot peg|
|Custom molded seat|
|Keyed ignition switch|
|State-of-charger (fuel) meter|
|Sealed beam hi/lo/flash headlight system|
|Turn and tail light package|
|Dual rear view mirrors|
Lectra meets Federal Motor Vehicle Safety Standards and is a "zero emission" vehicle.Range will vary depending upon many factors including driver actions, and weather and road conditions.
The LectraTM is a worldclass application of the most advanced technologies available in electric energy storage, display and delivery.
Whether you`re out for a leisurely ride around town, or running strong in demanding city traffic, you`ll appreciate the superior acceleration, braking and handling characteristics of the LectraTM.
The LectraTM has a low seat height (26"), a balanced feel, a tight turning radius (6-1/2 ft.), and requires no shifting or "warm up". And, the LectraTM is virtually maintenance free. These characteristics make the LectraTM a perfect motorbike for easy riding around town .... may be we should call it a "townbike" instead of a "motorbike"?
People just getting started in EVs or motorbikes can appreciate the easy riding, no hassle characteristics of the LectraTM. But, it is also a world-class motorcycle product that brings a new riding experience to even the veteran motorcycle rider.
The "Cost Of Ownership" of a product such as the Lectra can be broken down into four basic catagories:
- Initial purchase price
- Fuel costs
- Insurance costs
- Maintenance costs
The Lectra is designed to be very competitive in all four categories.
INITIAL PURCHASE PRICE: The Lectra's price competes with small motorcycles or large scooters.
FUEL COSTS: The Lectra uses 2 kilowatt-hours per charge. Electricity rates in most areas average $0.10 to $0.20 per kilowatt-hour. Therefore, the Lectra can be recharged for as little as 20 cents! This is significantly less than the price of gasoline fuel.
INSURANCE COSTS: The Lectra can be insured with rates similar to a 125cc scooter. Insurance can be under $100 per year, for basic liability coverage. This is significantly less expensive that an automobile or a large motorcycle.
MAINTENANCE COSTS: This is where the Lectra is very attractive. The Lectra does not have spark plugs, carburators, oil filters, gas filters, air filters, exhaust pipes, or gas tanks.
In fact, the Lectra requires only simple maintenance, offering savings to the Lectra owner of perhaps hundreds of dollars compared to a gasoline motorcycle. Lectra maintenance includes: drive chain lubrication and tensioning, checks for tire and brake pad wear, checks for light bulb operation, and regular washing to keep your Lectra looking great! Think of all the time you'll save.
With the Lectra's "regen" braking, brake pad life is significantly longer than most gasoline-powered motorcycles.
Even after factoring the periodic replacement of batteries, the Lectra should prove to be low in cost to own and operate.
And, the Lectra comes with a one-year warranty!
The Lectra has the power to climb hills and keep up with most city traffic. It is designed for easy riding around town. It also happens to be an excellent "starter" motorcycle.
Here are some great features of the Lectra that make riding easy:
INSTANT ON - NO "WARM UP": Have you ever started your gasoline motorcycle early in the morning. Usually, you need to warm up the engine before it will run right and be safe in traffic. Maybe your neighbors know that sound all too well! But, the Lectra is solid state -- no warm up needed. Just click it on and you have full power at your fingertips. Quiet, clean and ready to go!
NO SHIFTING: The Lectra has just one gear that takes it from zero to top speed. No more shifting or clutching.
LOW SEAT HEIGHT: With a seat height of just 26 inches, the Lectra is sized for just about anyone.
EASY AROUND TOWN: The Lectra has a sharp turning radius (6-1/2 ft.), a low center of gravity and a balanced feel making it easy to ride around town.
LOOKING GREAT: The Lectra is the only electric motorcycle on the market. Women tell us that it is a "guy magnet". In fact, you will probably find that lots of people wave, give you the "thumbs up", or stop to ask you about your Lectra. It is a GREAT attention grabber!
MOTORCYCLE SAFETY FOUNDATION: If you are just starting to ride, or if you want to hone your riding skills further, contact the Motorcycle Safety Foundation. They have some great publications and offer some nice training courses. Tel: (800) 669-7994
The VR24TM advanced electric drive system coupled to fat Dunlop tires are accurately controlled from your finger tips. The anti-lock electrically-assisted regenerating rear brake and floating caliper front disk brake provide smooth, powerful braking when you need it. Included is the convenience of on-board, fully automatic charging and a maintenance-free energy storage system.
VR24TM DRIVE SYSTEM
EMB is one of the first companies to commercialize an advanced variable reluctance (VR) electric drive system for vehicle drive applications. VR motor technology is a compact, highly efficient and brushless motor technology. A new motor structure (patent pending) combined with custom computer controls provide superior performance at a competitive price.
A unique feature of the VR24TM is its electronically assisted braking mode. Electrical braking extends vehicle range and preserves brake life by turning the vehicle`s kinetic energy into stored electrical energy during braking. For added safety and control, the VR24TM also incorporates "antilock" braking features, and a variety of safety interlock controls.
The VR24 drive system includes a regenerative braking mode. This turns the vehicle's kinetic (moving) energy into electricity when the regen brake is commanded. While regen braking does return some electric energy back to the batteries, it is not a perfect system.
The amount of energy returned to the battery during regen braking depends upon many factors, including your speed, the voltage level of the battery pack, and the efficiency of the regen braking system.
EMB's tests have confirmed that regen braking is most efficient at returning electric energy to the batteries when:
(1) Battery voltage is high (> 50% charge), and
(2) Speed of the vehicle is less than 15 mph
Regen braking works very well at slowing the Lectra .... it is a form of power braking. However, excessive use of regen braking can cause the VR24 drive to overheat. This is because part of the energy is converted to heat, and part is converted to electric energy for the batteries.
In general, coasting to a stop is much better for increasing vehicle range than using regen braking. However, using regen braking will provide more range that using only the friction (disk) brakes on the vehicle.
ADVANCED ENERGY STORAGE
The EMB smart battery charger is optimized for use with Lectra`s valve-regulated energy storage system. This system will not spill or leak and is designed for thousands of miles of reliable operation. With proper care, owners can expect up to 9,000 miles of useful life before replacement. EMB backs Lectra with a one year warranty.
The on-board charger is compact and fully automatic. Built in smarts allow Lectra to be conveniently recharged from almost any electrical power outlet (90 to 260 volts, 47-63 hertz).
A State-Of-Charge (SOC) meter tracks the level of stored energy.
The charger, motor electronics and electrical systems are resistant to water and dirt penetration, providing years of reliable service.
In most areas, a full recharge will cost about 10-20 cents. Couple this with ultra low maintenance requirements, and we think you will find Lectra excites your pocketbook as much as your spirit.
The Lectra uses four (4) advanced lead-acid batteries. With proper care and use, the battery pack will remain maintenance free and provide years of reliable service.
The battery pack is designed to provide 300-350 deep discharge/charge cycles (100% to 10% charge). Assuming a range of about 30 miles per charge, you can expect more than 9,000 miles (300-350 cycles times 30 miles per cycle) of battery life.
In general, to insure long life, batteries should be charged whenver possible, for as long as possible. The Lectra should be stored with fully charged batteries. The batteries used in the Lectra do NOT have a "memory" effect. You can charge them at any time, and the charger used on the Lectra is fully automatic ... just plug in and walk away!
The batteries are built by Optima Battery Company of Denver, Colorado. Replacement batteries are available from EMB, an EMB dealer, Optima, or through most Interstate battery distributors. Replacement cost is approximately $550-$600. Please recycle!
The Lectra uses a "state-of-charge" (SOC) meter to estimate the amount of energy remaining in the battery pack.Accurate measurement of battery power is still a developing science. Two basic approaches are commonly used:
The Lectra, when new, holds about 85 amp-hours of energy. That means the battery pack can supply 85 amps of current for about one hour. As the batteries are used, the amount of energy that can be stored will rise to about 105 amp-hours. This occurs after about 50 charge cycles of the battery pack.
The Lectra uses an amp-hour counter that is set at about 80 amp-hours. There are five LED lights on the Lectra to indicate how much energy remains -- each light equates to 20% charge, or about 16 amp-hours. Whenever you use your Lectra, battery current leaves the battery and is used to drive the wheel, lights, horn, etc.The Lectra's SOC meter counts how many amp-hours are used and keeps track of this data. When you recharge the battery pack, the meter counts amp-hours going back in the battery pack.
Because amp-hour capacity varies with battery cycling, the SOC meter is not exact. For example, if your batteries can deliver 105 amp-hours, the SOC meter only keeps track of 80 of those amp-hours. This means that when the SOC meter reads empty, you actually have about 25 amp-hours left (105 minus 80).
The amount of energy remaining in a battery can be correlated to "open-circuit" battery voltage. This is the voltage the battery has when there in no load on the battery (i.e. it is no being used). As long as the battery is in an open circuit state, the voltage is an accurate measurement of the energy remaining. However, as soon as power is pulled from the battery (i.e. a loaded, or "closed" state), then voltage drops in proportion to the amount of current being drawn from the battery. In this way, a volt meter can also tell an experienced person how much current is being drawn, by watching the amount of voltage swing -- from "open circuit" to a loaded condition on the battery.
Usually, an electric vehcile is having current drawn from the battery. Therefore, using a volt meter requires that the driver shut the throttle off, let the battery voltage "rest", then see how much energy remains. A full battery pack on the Lectra will exhibit about 26.5 volts. An empty battery pack exhibits about 20.5 volts. Therefore, if you have 23.5 volts remaining, the battery pack is about half full.
Digital control alogrithms can be used to compensate for fluctuating voltage -- voltage fluctuates whenever a load is placed on the batteries.
The VR motor -- the world's simplest motor. How does it work?
The principle for the Variable Reluctance (VR) motor has been known for more than a century. But the rapid developments within power and control electronics during recent decades have made the technology especially interesting today.
The VR, motor is an electronic motor in that it requires electronics to function. The reason is that the motor current must be switched between the various phase windings according to the rotor rotation, thereby the name Variable Reluctance. To achieve this, it is necessary to continuouslv measure the rotor's angular position. This is achieved either by using a separate shaft sensor or by using a sensor-less measurement method.The EMB VR24TM uses a shaft sensor.
Sometimes the variable reluctance motor is called "switched reluctance" motor, or simply "reluctance motor". This is slightly misleading since the term also includes other types of motor. However, EMB refers to it as a variable reluctance or VR motor.
The VR, motor has sometimes been called the world's simplest motor. This is easy to understand when looking at its construction. Just like most other types of motor, it has a stationary part, the stator, which consists of a number of windings on an iron core. The moving part, the rotor, consists only of iron, often in the form of laminated sheets pressed on to the rotor axle.
The lack of magnets, windings, and slip rings or brushes in the rotor makes the motor itself robust and relatively easy to manufacture.
To control the motor torque or speed, some degree of electronics is always re-quired. Depending on the application and requirements, anything from very simple to quite sophisticated electronic designs are used.
Customers normally choose the VR drive system instead of other types because of some of the following features:
- The motor is brushless and thereby maintenance-free.
- The motor is easy to manufacture.
- The efficiency is high compared to conventional DC and AC motors.
- The relationship between efficiency and price is advantageous compared to all other solutions including so-called brushless DC motors.
- At low speed, almost no losses in the rotor are generated. The losses only occur in the stator, which means that the motor is easy to cool and can thus be small.
- The motor can be designed for use in very high ambient temperatures.
- Accurate speed control is achieved at a low cost.
- The motor can easily be mechanically adapted or even integrated with the equipment or machine that is driven.
Principle of VR motors
Today's most common electric motors are based on the principle that force is created by interaction between magnetic fields.
However, the VR motor uses another principle, namely that a piece of iron placed in a magnetic field will always align in the minimum reluctance position -- i.e. where the magnetic field meets the lowest resistance.
In an VR motor, both the rotor and the stator have iron cores with salient poles. The windings around the poles of the stator are diametrically connected, two and two, as phase windings.
An VR motor can have one or more phases, although two or three are most common. The EMB VR24TM is a two-phase design. Due to the salient poles in the rotor and stator, each phase circuit has a reluctance that varies with the rotor position.
When a phase winding is energized, the rotor tries to position itself to achieve the minimum reluctance for that phase just as the rotor approaches equilibrium, current is switched to the next phase winding so that rotation is maintained.
Since normally only one or a maximum of two phase windings actually contributes to a driving torque at any one time, it is necessary to switch the current between the various phases at exact rotor positions. The controlling electronics ensure that the current and voltage are switched in sequence between the phases of the motor so that they follow the rotor.
Variable speed and torque
The torque produced depends on how much current flows through each phase winding. The torque of the VR motor is thereby controlled by increasing or decreasing the phase current. In this way, the speed can also be varied.
Since the rotor position is continuously monitored, the speed can easily be calculated. Therefore, an VR motor system always permits precise speed control without the need for extra speed sensors. EMB uses this feature to integrate anti-lock braking features in the VR24TM.
Robust and easy to cool
The motor is made of iron and copper. Both the stator and rotor have a simple iron core of laminated metal or in special cases, solid iron.
The motor windings are made as phase pole windings and are mounted on each of the pole pieces on the stator. This simple construction makes the motor very robust and suitable for harsh environments.
Since the rotor only consists of iron, and heating only primarily occurs in the motor windings close to the periphery of the motor, the motor is easy to cool and is suitable for operation at high temperatures.
Brushless and without magnets
One advantage of the VR motor compared with the classic DC motor is that it is brushless. This means that no mechanical commutators or slip rings are necessary to transfer current to the rotor.
In addition, the VR motor does not contain any magnets that otherwise are sensitive to high temperatures, mechanical stresses or electromagnetic radiation.
At a first glance, the VR motor looks like a simple motor to construct and control. However, this is not the case. Although it is relatively easy to get the motor to rotate, one soon finds that considerable know-how is necessary to obtain the required prop-erties. EMB spent many years, working closely with VR experts to develop the VR24TM.
What are the difficulties? They are primarily the following:
- The relationship between current and torque is non-linear, which means that it is difficult to simulate and analyze the characteristics of the motor. To solve this, developers uses advance Finite Element Analysis (FEA) programs to analyze and simulate VR motors.
- Switching between phase windings must occur at exactly the correct angle to provide smooth rotation. To determine these angles, sophisticated calculations or time-consuming measurements are required.
- To achieve a smooth rotation without torque ripple, it is necessary to continuously control the current in relation to the rotor position, even between the phase winding switchings.
- To achieve high efficiency, the motor and the controller have to be optimized as one unit. The EMB VR24TM motor and controller were develop as an integrated system.
Increased use of VR technology
So far, the development within VR tech-nology has been confined to a number of narrow areas of use with special require-ments. The fact that VR technology is not sold in the form of general drive systems, but rather as customized systems in large series, will probably also apply in the future. The EMB VR24 drive was developed specifically for EMB`s electric motorbikes. It may also work well on vehicles requiring similar power characteristics, such as electric go-karts.
The properties of the motor make it suitable for applications where a high degree of optimization is required. However, for cost reasons, the prerequisites for carrying out such an optimization are that the manufacturing volumes are sufficiently large. Therefore, the dominant target group for the technology is and will continue to be the OEM market, where the drive system is an integrated part of the customer's product.
VR technology is now beginning to be generally accepted and is currently used within a number of different areas of use, such as washing machines, vacuum cleaners, pumps, compressors, ventilation systems and electric vehicles of various types. New areas where the technology is expected to gain a foothold are military equipment, within the automotive industry and for powering hand tools.
Altering Top Speed
The Lectra is supplied with a 13 tooth chain sprocket in front and a 54 tooth sprocket in the rear. (we use a #420 chain to drive the rear wheel) EMB considers this set up ideal for general city driving and hill climbing.It is the set up we developed for the demanding streets of San Francisco. With the 13/54 set up your Lectra will accelerate quickly to 30-35 mph, then more slowly to a top speed of 42-45 mph. With this set up you will also be able to start from a stop on almost any hill found on city streets.
Upon request, EMB can also supply a 15 tooth sprocket in front, in place of the 13 tooth standard sprocket.With a 15 tooth sprocket, the top speed will be increased to about 51 mph, and acceleration will be stronger up to about 40 mph. However, some hill climbing ability will be lost. Range will also suffer if you maintain high speeds while driving (See explanation below).
Although EMB considers the factory set ups to be ideal for the Lectra design, it is possible to change the drive ratio, and thus alter top speed and acceleration characteristics. Before attempting this, there are several aspects of vehicle design which should be carefully considered.
The EMB factory set up for the Lectraä, provides both hill climbing abilities and a top speed of about 45 mph. The drive system has an overall speed reduction ratio of about 20:1. The motor peak speed is limited through software to about 15,800 RPM. The motor speed is transmistted to the rear wheel first through a helical gear and pinion in the motor that provides 5:1 speed reduction, and then via a#420 chain and sprocket set that provides a further 4:1 speed reduction.
The front sprocket (motor side) is a standard Honda type sprocket for #420 chain. If you would like to alter the chain ratio, this can be accomplished by changing the size of the front sprocket. For each tooth you increase in size, the top speed will theoretically increase by 7%. The opposite is true if you decrease the size of the front sprocket(or increase the size of the rear sprocket).
Less chain ratio (i.e. les than 20:1) equates to higher top speed, but less hill climbing ability and acceleration. More chain ratio equates to lower top speed, but more acceleration and hill climb ability.
The VR24TM drive system has about 8 HP peak power, so there is a limited as to how fast the Lectraä will go with the available horsepower. Remember, wind resistance goes up exponentially with speed. The faster you go, the more the wind tries to stop you.
As an experiment, to test the role of wind resistance, trying tucking -- see how far you go, and see what your top speed is. Then ride again in an upright position -- compare range and top speed.
Also, it is important to note that the VR24TM drive system is rated for about 3 HP continuous power (this is the horsepower at about 30 mph cruise speed). If you command more than 3 HP, or travel faster than about 30 mph for extended periods of time, it is probable that the temperature ("T") light will illuminate on the dash board. This means that power is being limited to protect the VR24TM from overheating. If the temperature continues to climb the VR24TM will shut down and the "T" light will blink, indicating an overtemperature shut down has occured. Too much speed can equate to too much heat and overtemperature problems.
One other thing you should know, about batteries, if you are thinking about changing chain ratios or altering top speed. Batteries actually change the amount of energy they will deliver ("Capacity") depending upon how quickly they are discharged. This is called the "C" rate. "C" stands for "Capacity".
"C/1" means the entire battery capacity is discharged in 1 hour, "C/0.5" means the entire battery capacity is discharged in one-half (0.5) hour, and so on.
In general, the higher the number in the denominator, the better the battery will perform. In other words, discharging slowly (gentle riding) will equate to more battery capacity and longer range. For example, the Optima battery delivers 65 amp-hours at a C/20 rate, but only 52 amp-hours at a C/2 rate, and only about 42.5 amp-hours at a C/1 rate.
EMB uses the Optima D750S batteries in a series-parallel configuration. This means there are two batteries in series that provide 24 vdc. There are, in turn, two of these 24vdc battery series that are run in parallel, essentially doubling the power and energy that a single 24vdc battery series would provide.
The LectraTM with its factory set-up, is designed to cruise at 28-30 mph for about one hour. In other words, it is designed with a C/1 battery discharge rate. The LectraTM uses two sets of batteries, and the entire battery pack provides about 42.5 amp-hours x 2 packs = 85 amp-hours (when new, and gaining about 25% capacity after 100 cycles! Batteries work better after a break-in period.).
If you travel faster than 30 mph, the battery discharge rate will be higher than C/1, perhaps C/0.5. In other words, the faster you go, the faster the batteries discharge. Because batteries are chemical processes, they have a limit as to how fast the chemical processes can take place. By discharging the batteries quickly, some of the capacity is lost. The LectraTM battery pack normally (at C/1) provides about 85 amp-hours of energy. If you discharge at a faster rate, for example C/0.5, then the battery capacity will be less than 85 amp-hours.
Faster speed means less range, because not only do you have more wind resistance, but you also have less battery capacity!
Altering the set up of your LectraTM may also change the status of your EMB factory warranty. Read your warranty, and please consult with EMB or an EMB dealer if you have questions.