Magtrol WB Series User Manual page 22

Chapter 1 – Introduction
Specifications
poWDer DYnaMoMeter operating principles
The PB Powder Dynamometers contain, as their name
suggests, a magnetic powder. The electrical current passing
through the coil generates a magnetic field, which changes
the property of the powder, thus producing a smooth braking
pB DYnaMoMeter ratings
Rated Torque
Model
N·m
1 PB 43 5
2 PB 43
10
* Voltage at 20 °C is 24 volts.
Optical Speed Sensor
Each 43 Series PB Dynamometer has an optical speed sensor
with a 30-bit pulse wheel delivered as standard. For better
speed resolution in low speed applications, Magtrol offers a
600-bit or 6000-bit speed pickup (encoder) as an option.
pB torque–speeD–poWer curves
The diagram below shows the characteristic curves for the 43 Series Powder Dynamometers.
100
10
1
0.1
10
4
Drag Torque
De-energized
lb·ft N·m oz·in
3.6 0.1 14.1
7.3 0.2 28.3
2 PB 43 (TORQUE)
1 PB 43 (TORQUE)
100
Rotation Speed (rpm)
torque through friction between rotor and stator. The Powder
Dynamometers (PB) produce their rated torque at zero
speed. The element to be tested can be loaded at standstill to
determine the starting torque.
Nominal Input Inertia
kg·m² lb·ft·s²
-4 -4
1.41 × 10 1.03 × 10
-4 -4
2.40 × 10 1.77 × 10
Cooling Water Consumption
For all PB models:
955 rpm
1000
12
Magtrol WB/PB Dynamometers
Rated Rated Max.
Power Speed Speed
kW rpm rpm
0.5 955 4000
1 955 4000
≈ 30 l/kWh at ∆t = 30 °C
≈ 8 gal/kWh at ∆t = 86 °F (US)
4000 rpm
10
1
0.1
0.01
10,000
M AGTROL
PB 43
Excitation
Current*
A
1
2
(Metric)