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Magtrol Hysteresis Dynamometers
ED DESCRIPTION
With Magtrol's Engine Dynamometers, high performance
motor testing is available to manufacturers and users of small
engines. Magtrol's Engine Dynamometers have been designed
to address the severe, high vibration conditions inherent in
internal combustion engine testing.
Magtrol's Engine Dynamometers are highly accurate (± 0.25%
of full scale) and can be controlled either manually or via a PC
based Controller. For a small engine test stand, Magtrol offers
a full line of controllers, readouts and software.
As with all Magtrol Hysteresis Dynamometers, engine loading is
provided by Magtrol's Hysteresis Brake, which provides: torque
independent of speed, including full load at 0 rpm; excellent
repeatability; frictionless torque with no wearing parts (other
than bearings); and long operating life with low maintenance.
ED APPLICATIONS
The Engine Dynamometers are ideally suited for emissions
testing as set forth in CARB and EPA Clean Air Regulations. The
Dynamometers will offer superior performance on the production
line, at incoming inspection or in the R&D lab.
OPERATING PRINCIPLES
ROTOR
(Drag Cup)
HUB
Magtrol Hysteresis Dynamometers absorb power with a
unique Hysteresis Braking System which provides frictionless
torque loading independent of shaft speed. The Hysteresis
Brake provides torque by the use of two basic components—a
reticulated pole structure and a specialty steel rotor/shaft
assembly—fitted together but not in physical contact. Until the
pole structure is energized, the drag cup can spin freely on its
shaft bearings. When a magnetizing force from the field coil is
applied to the pole structure, the air gap becomes a flux field
and the rotor is magnetically restrained, providing a braking
action between the pole structure and rotor.
© 2016 MAGTROL | Due to continual product development, Magtrol reserves the right to modify specifications without forewarning.
DATASHEET
DYNAMOMETER SELECTION
Magtrol's Hysteresis Dynamometers cover a wide range of
Torque, Speed and Mechanical Power ratings. To select the
appropriate size Dynamometer for your motor testing needs,
you will need to determine the Maximum Torque, Speed and
Power applied to the Dynamometer.
MAXIMUM TORQUE
The Magtrol Hysteresis Absorption Dynamometer will develop
braking torque at any speed point, including low speed and stall
conditions ("0" rpm). It is important to consider all torque points
that are to be tested, not only rated torque, but also locked
rotor and breakdown torque. Dynamometer selection should
initially be based on the maximum torque requirement, subject
to determining the maximum power requirements.
MAXIMUM SPEED
This rating is to be considered independent of torque and
power requirements, and is the maximum speed at which the
Dynamometer can be safely run under free-run or lightly loaded
conditions. It is not to be considered as the maximum speed at
which full braking torque can be applied.
MAXIMUM POWER RATINGS
These ratings represent the maximum capability of the
Dynamometer Braking System to absorb and dissipate heat
POLE STRUCTURE
generated when applying a braking load to the motor under
SHAFT
test. The power absorbed and the heat generated by the
Dynamometer is a function of the Torque (T) applied to the motor
BALL BEARINGS
under test, and the resulting Speed (n) of the motor. This is
expressed in these power (P) formulas:
FIELD COIL
SI:
P (watts) = T (N·m) × n (rpm) × (1.047 × 10
English: P (watts) = T (lb·in) × n (rpm) × (1.183 × 10
Metric: P (watts) = T (kg·cm) × n (rpm) × (1.027 × 10
AIR GAP
All of Magtrol's controllers, readouts and software
calculate horsepower as defined by 1 hp = 550 lb·ft / s.
Using this definition:
The Dynamometer's ability to dissipate heat is a function of
how long a load will be applied. For this reason, the maximum
power ratings given are based on continuous operation under
load, as well as a maximum of 5 minutes under load.
To safely dissipate heat and avoid Dynamometer failure, the
maximum power rating is the most important consideration
in selecting a Dynamometer.
11
Chapter 1 – Introduction
HD
SERIES
-1
)
-2
)
-2
)
hp = P (watts) / 745.7
Page 2 / 16
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