36
Magtrol WB/PB Dynamometers
Chapter 1 – Introduction
4
MAGTROL
pB DynaMoMeter ratings
Specifications
* Voltage at 20 °C is 45 volts.
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
1000
10,000
100
10
10
100
1
0.1
10
10
100
1000
2000 rpm
382 rpm
10,000
Speed Limit f
or PB
Rotation Speed (rpm)
To
rque (N·m
)
Po
wer (kW
)
4 PB 15 (TORQUE)
2 PB 15 (TORQUE)
1 PB 15 (TORQUE)
4 PB 15 (PO
WER)
2 PB 15 (PO
WER)
1 PB 15 (PO
WER)
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.
poWDer DynaMoMeter operating principles
pB torque–speeD–poWer curves
The diagram below shows the characteristic curves for the 15 Series Powder Dynamometers.
Optical Speed Sensor
Each 15 Series PB Dynamometer has an optical speed sensor
with a 60-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.
Cooling Water Consumption
For all PB models:
≈
30 l/kWh at
∆
t
= 30 °C (Metric)
≈
8 gal/kWh at
∆
t
= 86 °F (US)
Model
Rated Torque
Drag Torque
De-energized
Nominal Input Inertia
Rated
Power
Rated
Speed
Max.
Speed
Excitation
Current*
N·m
lb·ft
N·m
lb·in
kg·m²
lb·ft·s²
kW
rpm
rpm
A
1 PB 15
300
221
6
53 5.40 × 10
-2
3.98 × 10
-2
12
382
2000
4
2 PB 15
600
442
12
106 1.08 × 10
-1
7.96 × 10
-2
24
382
2000
7.5
4 PB 15
1200
885
24
212 2.16 × 10
-1
1.59 × 10
-1
48
382
2000
12
PB 15