Magtrol's 15 standard 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 generated when applying
a braking load to the motor under test. The power absorbed and
the heat generated by the Dynamometer is a function of the Torque
(T) applied to the motor under test, and the resulting speed
(n) of the motor. This is expressed in these power (P) formulas:
| SI: |
P (watts) |
= |
T (N·m) |
× |
n (rpm) |
× |
(1.047 ×
10-1) |
| English: |
P (watts) |
= |
T (lb·in) |
× |
n (rpm) |
× |
(1.183
× 10-2) |
| Metric: |
P (watts) |
= |
T (kg·cm) |
× |
n (rpm) |
× |
(1.027
× 10-2) |
All
of Magtrol's controllers, readouts and software
calculate horsepower
as defined by 1 hp = 550 lb·ft / s. Using this definition:
|
|
hp |
= |
P (watts) |
/ |
745.7 |
To calculate power, use Magtrol's online motor
power calculator
|
|
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.
|
