3B Scientific Motor User Manual
3B SCIENTIFIC
12-V DC motor with non-ferrous rotor U8552330
Instruction sheet
02/08 DML/ALF
®
PHYSICS
1 Lever
2 Pulley
3 Supporting holder
4 Stem
5 Motor
6 4-mm connectors
1. Safety instructions
• Do not exceed the maximum permissible op-
erating parameters (see Section 3 – Technical
data).
Long hair, loose clothing, or jewellery could get
caught and entangled in the rotating components.
• To prevent this danger, it is advisable to wear
a hairnet in the case of long hair.
• Do not wear unsuitable clothing or jewellery.
While operating with the belt pulley and the drive
belt, there is the additional danger that parts of the
body, e.g. fingers, may get pulled in or caught
between the belt and the pulley.
• Do not touch or hold any rotating components
of the experiment set-up.
The DC motor can also be used as a generator.
• In this state, do not connect any power supply
to the connectors.
2. Description
The DC motor is a small, compact motor with a
non-ferrous rotor and is used as an excitation unit
in experiments on mechanics, simple harmonic
oscillation and electricity. It can also be used as a
tachometer. Its low moment of inertia, in conjunction with a high starting torque, provides a short
acceleration time. Owing to the strong permanent
magnet of the stator, the motor is highly efficient.
The special brush and commutator arrangement,
in conjunction with friction bearings, guarantees a
long working life and low running noise.
The axle of the motor is equipped with a threaded
bush to which a pulley is attached by means of a
thread. This pulley allows other wheels and levers
to be attached to the axle for the excitation of
mechanical oscillations and waves.
The DC motor is attached to an angled supporting
bracket with stem. 4-mm connectors on the
bracket are responsible for supplying the equipment with electricity as well as for tapping the
output voltage in generator mode.
1
3. Technical data
Nominal voltage: 12 V DC
Max. permissible operating voltage: 15 V DC
Idling speed: 3800 rpm
Nominal speed at rated torque: 3100 rpm/5 mNm
Nominal current without load/
with nominal load: 55 / 210 mA
Power consumption: 2.9 W
Voltage per speed of rotation: 3.6 … 4.4
mV
rpm
4. Sample experiments
Rotor impedance: 12 Ω
Starting torque: 29 mNm
Acceleration time (no-load): 12.5 ms
Direction of rotation: Reversible
Max. permissible bearing load:
radial at shaft-end: 5.0 N
axial: 0.5 N
∗
In the case of older motor models from an earlier
range, the voltage sensitivity is in the range of:
2.8 … 3.6
mV
rpm
Fig. 1: Experiments on uniform motion (top) and friction (bottom)
Fig. 2: Excitation of transverse waves in a rubber band using a sine wave generator
2
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