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There are at least 3 different types of brake tester used to calculate the braking efforts and efficiencies of a motor vehicle. Roller brake testers, which consist of a chassis with a driven roller system; plate brake testers, which consist of 2 parallel measuring plates, and decelerometers which are usually hand held devices. == Roller Brake Testers == A roller brake tester is a method of allowing the dynamic assessment of the braking system of a motor vehicle, whilst the vehicle itself is in a static condition. This type of brake tester is normally used in UK garages when used as part of an inspection lane for the MOT test. Roller brake testers consist of a mechanical floor unit which contains electrical motors, two independent sets of three measuring rollers, brake force transducers and additional safety sensors.〔(【引用サイトリンク】url=http://garageequipmenttechnology.wordpress.com/2012/11/22/how-it-works-roller-brake-testers/ )〕 The driving rollers operate at a low (known) speed using a gearbox and motor arrangement and during a test measurements of the maximum braking force are taken by applying the vehicle brakes which induces a reaction force on the electric motor itself. An electric transducer with strain gauges then measures the individual induced forces which are acting during the deceleration phase in order to calculate the individual braking forces for each wheel. In order to minimise any inaccuracy and variation in the measurement, the roller diameter is sufficiently large to reduce the effects of the mechanical relaxation, or flexing, of the tyre itself. A special coating on the rollers is designed to be very wear resistant and provide good friction values, both in wet and dry conditions. A third smaller roller, on each side between the driving rollers, has two functions: The first is to detect if a vehicle is present in the roller bed (a built in safety device to prevent the motor from starting up unless a vehicle is in the brake tester), the second function is to detect when and if tyre slippage occurs in order to make the measurement before a maximum, predefined value of time passes. During the test, the computer measures the brake force values and the system will calculate the imbalance between the left and right brake forces of an axle, as well as the brake efficiency of the service brake and the parking brake provided that a vehicle weight is either inputted manually or by using an integrated weighing system. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Brake tester」の詳細全文を読む スポンサード リンク
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