
5
Magtrol WB/PB Dynamometers
Chapter 1 – Introduction
4
MAGTROL
Specifications
pB DYnaMoMeter ratings
* Voltage at 20 °C is 24 volts.
poWDer DYnaMoMeter operating principles
pB torque–speeD–poWer curves
The diagrams below shows the characteristic curves for the 2.7 Series Powder Dynamometers.
Optical Speed Sensor
Each 2.7 Series PB Dynamometer has an optical speed sensor
with a 30-bit pulse wheel delivered as standard.
** Cooling Circuit
The 2.7 Series PB Dynamometers are available with (K) or
without a cooling circuit. The cooling water consumption for
all PB-8K models is:
≈
30 l/kWh at
∆
t
= 30 °C (Metric)
≈
8 gal/kWh at
∆
t
= 86 °F (US)
4
P
B
2.
7-
8-
K
(P
OW
ER
)
2 PB 2.7-8-K (P
OW
ER
)
1
P
B
2.
7-
8-
K
(P
OW
ER
)
1000
100
10
1000
100
10
10
100
1000
10,000
10,000 rpm
2390 rpm
100,000
Speed Limit f
or PB
Rotation Speed (rpm)
To
rque (mN·m)
Po
wer (W)
4 PB 2.7-8-K (TORQUE)
2 PB 2.7-8-K (TORQUE)
1 PB 2.7-8-K (TORQUE)
4
P
B
2.
7-
8
(P
OW
ER
)
2
P
B
2.
7-
8
(P
OW
ER
)
1
P
B
2.
7-
8
(P
OW
ER)
1000
100
10
1000
100
10
10
100
1000
10,000
3000 rpm
320 rpm
100,000
Speed Limit f
or PB
Rotation Speed (rpm)
To
rque (mN·m)
Po
wer (W)
4 PB 2.7-8 (TORQUE)
2 PB 2.7-8 (TORQUE)
1 PB 2.7-8 (TORQUE)
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
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.
Model
Rated Torque
Drag Torque
De-energized
Nominal Input Inertia
Rated
Power
Rated
Speed
Max.
Speed
Excitation
Current*
N·m
oz·in
mN·m
oz·in
kg·m²
lb·ft·s²
W
rpm
rpm
A
1 PB 2.7-8
0.6
84
18
2.54
1.49 × 10
-5
1.09 × 10
-5
20
320
3000
0.5
2 PB 2.7-8
1.2
169
30
4.24
2.33 × 10
-5
1.71 × 10
-5
40
320
3000
1
4 PB 2.7-8
2.4
339
48
6.79
4.03 × 10
-5
2.97 × 10
-5
80
320
3000
2
1 PB 2.7-8K ** 0.6
84
18
2.54
1.49 × 10
-5
1.09 × 10
-5
150
2390
10,000
0.5
2 PB 2.7-8K ** 1.2
169
30
4.24
2.33 × 10
-5
1.71 × 10
-5
300
2390
10,000
1
4 PB 2.7-8K ** 2.4
339
48
6.79
4.03 × 10
-5
2.97 × 10
-5
600
2390
10,000
2
PB 2.7