A TYPICAL MBS DYNAMOMETER SYSTEM SCHEMATIC


The above drawing shows a typical MBS Dynamometer. All components shown are included in the basic dynamometer.
The cost of the above shown system is $14,500. Normally these dynamometers are in stock.
Included in with all dynamometer series are the following:
          1. The dynamometer
          2. The computer including the software to display torque, power etc.
          3. The control module
          4. One motor adapter (additional adapters are available from MBS)

 

VARIOUS USES AND TYPES OF DYNAMOMETERS

Dynamometers are used primarily for measuring motor torques and therefore horsepower as a function of motor speed. Though most commonly used for electric motors, dynamometers are also used for testing gasoline engines and various other types of motors. See page 2 for model numbers.

A dynamometer requires a means of dissipating the energy produced by the motor under test. Magnetic Brake Systems (MBS) uses magnetic brakes and electric generators for dissipating this energy. A detailed description and performance curves are given on the MBS website, www.magbrakesystems.com, under the magnetic brake section.

The motors to be tested may be mounted in various ways. MBS manufactures FACE MOUNTED, BASE MOUNTED and CARRIAGE MOUNTED dynamometers. Typically the fractional horsepower motors are face mounted, the 1 to 3 hp motors are base mounted and 2 to 50 hp motors are carriage mounted.

The face and base mounted dynamometers may be either directly couple or belt coupled to the motor under test.  The belt coupled devices have the advantage that torque or speed may be easily increased or decreased by a factor of seven; thus allowing for a VERY LARGE TORQUE RANGE of motors which can be tested on one dynamometer.

The MBS dynamometers are noteworthy in the method of TORQUE MEASUREMENT.  The motors under test are pivoted about their axis and the torque measurement is made directly by measuring the torque on the motor.  This eliminates problems with non-linearities in the brake, belt and bearing friction and particularly at higher speeds air drag on the belt and braking devices.  Torque can be accurately measured within better than one percent.

The measurement information obtained is captured and displayed by a laptop computer and if desired may be printed in the form of graphs or tables. The raw data is also available to export in tab delimited format.

 

THE DISTINCT ADVANTAGES AND DIFFERENCES OF THE MBS DYNAMOMETERS

The torque of the Motor Under Test (MUT) in an MBS dynamometer is measured directly off of the MUT housing. Unlike other dynamometers, the MBS torque measurement is independent of ball bearing friction (from the torque transducer and magnetic brake) or air drag (from the torque transducer, shafts, belts or the brake). These measurement errors become significant at higher speeds. Consequently the torque measurements made by the MBS dynamometers have a far higher accuracy with variation in test speed than most dynamometers.

The torque measurement accuracy is better than 1%.

Frequency response of the torque sensor is in excess of 10 kHz.

The short term power dissipation of the magnetic dynamometers is far higher than most comparable dynamometers; as high as 34,428 Watts (46.16 HP). The power dissipation of the generator dynamometers is of course continuous.

The MBS dynamometers are supplied in both direct couple or belt coupled units. The belt coupled units, though slightly more expensive to manufacture, have a far wider torque and speed range and higher testing speed than direct coupled units. This is achieved through a change in timing belt pulleys. The belt coupled units also have a far higher maximum speed e.g. in excess of 20,000 RPM.

The MBS dynamometers eliminate the cogging problem, exhibited by most magnetic brake dynamometers, at the start of brake rotation.