U8498299-115 [1017729]
3B SCIENTIFIC® PHYSICS
Leslie Cube with Heater
230 V, 50/60 Hz: 1017730 / U8498299-230
115 V, 50/60 Hz: 1017729 / U8498299-115
Instruction sheet
10/15 SD/UD
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9
Leslie cube on rotating base
Handle
LED status indicator
Setting buttons “+/-”
Display
“SET” button
Mains socket with switch
and fuse holder
Holder for thermopile
Voltage selector switch,
115/230 V
1. Safety instructions
The Leslie cube with heater conforms to all safety regulations for electrical measuring, control,
monitoring and laboratory equipment, as specified under DIN EN 61010, Section 1, and the
equipment has been designed to meet protection class I. It is intended for operation in a dry
environment, suitable for the operation of
electrical equipment and systems.
Safe operation of the equipment is guaranteed,
provided it is used correctly. However, there is
no guarantee of safety if the equipment is used
in an improper or careless manner.
If it may be assumed for any reason that nonhazardous operation will not be possible (e.g.
visible damage), the equipment should be switched off immediately and secured against any
1
unintended use.
In schools and other educational institutions, the
operation of the Leslie cube with heater must be
supervised by qualified personnel.
 Before using the equipment for the first time,
confirm that the specifications printed on the
rear side of the housing are compatible with
the local mains voltage.
 Before using the equipment, check the housing and the mains lead for any damage. In
the event of any malfunction/operational defect or visible damage, switch off the unit
immediately and secure it against unintended use.
 The instrument may only be connected to
the mains via a socket that has an earth
connection.
 Replace a faulty fuse only with one matching
the specifications stated at the rear of the
housing.
 Disconnect the equipment from the mains
before replacing a fuse.
 Never short the fuse or the fuse holder.
 The equipment may only be opened/repaired by qualified and trained personnel.
The Leslie cube can reach temperatures of up to 120°C.
surfaces are guaranteed to be located the same
distance from the thermopile throughout the
experiment and a constant temperature is also
guaranteed.
The 1017729 Leslie cube with heater is for operation with a mains voltage of 115 V (±10%),
and the 1017730 unit is for operation with a
mains voltage of 230 V (±10%).

3. Technical data
Do not touch the Leslie cube during the experiments, in particular while it is heating up
or cooling down. There is a risk of getting
burned. Only use the handle to turn the cube.
Mains voltage:
115 / 230 V AC ± 10%,
see rear of housing
Mains frequency:
50/60 Hz
Power consumption:
150 W
Fuses:
115 V: 2x 4 A slow-blow,
230 V: 2x 2 A slow-blow
Lamps:
120 V, 150 W,
socket: BA15d, design:
T4, order no.: 5008450
Temperature range:
40 - 120°C
Resolution:
1°C
Temperature display:
2-line LCD display for
temperature set-point
and actual temperature
Display accuracy:
5%
Ambient temperature:
5°C to 40°C
Max. relative humidity: 80%
2. Description
The Leslie cube with heater is a hollow aluminium cube used for quantitative investigation of
thermal radiation from a body as a function of
temperature and the nature of the surface. In
particular, it allows for qualitative verification of
the Stefan-Boltzmann law.
The cube can be rotated and has a lamp for
heating purposes as well as a temperature sensor for closed-loop control heating so that the
surfaces are at a set temperature, which can
also be adjusted. The side surfaces are polished, matt or painted white or black. The control unit makes it possible to set up the system
easily by means of setting buttons and a twoline display showing the temperature set-point
and the actual temperature. The temperature
display can be configured to display in °C or °F.
An LED indicates the operating status of the
heater. A holder attached to the control unit is
provided to accommodate a thermopile. All the
Contamination class:
2
Protection type:
IP20
Inside diameter
of holder:
10 mm
Dimensions:
Weight:
250 x 250 x 220 mm3
1,8 kg
4. Operation
To perform experiments using the Leslie cube,
the following equipment is also required:
1 Thermopile
1000824
1 Measurement amplifier @230 V
1001022
or
1 Measurement amplifier @115 V
1001021
1 Digital multimeter P3320
1002784
1 HF patch cord, BNC/4 mm plug
1002748


2
Use the “SET” button to configure the temperature display for °C or °F.
The set-point for the temperature is adjusted
using the “+/-” buttons.
4.1 Changing the fuse
 Turn off the power switch and unplug the
mains plug.
 Lever out the fuse holder on the back of the
power supply with a flat-head screwdriver
(Fig. 1). Insert the screwdriver from the connector side of the fuse holder.
Fig. 1

5. Sample experiment
How thermal radiation from a body depends
on temperature and nature of surface
 Fasten the thermopile into its holder in such
a way that is aligned in the centre of the side
of the side of the Leslie cube it is facing and
at right angles to it.
 Connect the measurement output of the
thermopile to the voltage input of the measuring amplifier using a high-frequency cable
and set the measuring range to 10 mV.
 Connect the digital multimeter to the voltmeter sockets on the measuring amplifier and
set the measuring range to DC.
 Turn on the control unit. When the actual
temperature T0 has settled to a stable figure,
read off the value and make a note of it.
 Adjust the set-point for the temperature to T
= 40°C and record measurements, e.g. in
steps of 10° over a range 40°C ≤ T ≤ 120°C.
For each of the selected temperatures T,
read off the voltage U from the digital multimeter and make a note of both values as
soon as the actual temperature is equal to
the set temperature. Take the notes into account.
 Carry out a set of measurements for each of
the four different surfaces.
 Plot the voltages for all four sets of measurements against T4 – T04 on a graph (Fig. 2).
Notes:
The measurements can be distorted by external
influences (body heat, sunshine, radiators).
 To record each measurement, first wait till
actual temperature and the voltage have
both settled to stable values.
The voltage U measured is directly proportional
to the irradiance I = P/A, i.e. the radiation power
P per area A.
All temperatures need to be converted to Kelvin
as follows:
(1) K = °C + 273.15
Changing the fuse
Take out the blown fuse and replace it with a
new one of the correct specification. Press
the fuse holder back into place.
4.2 Changing the heater bulb
 Turn of the control unit and be sure to unplug it from the mains.
 Allow the Leslie cube to cool down to room
temperature.
 Open the cover of the Leslie cube by undoing the two cross-head screws at the top.
 First push the blown bulb of the heater lamp
in slightly, whilst turning it anti-clockwise,
then remove it.
 Hold the new heater lamp bulb (order no.:
5008450) with a cloth and plug it into the
socket. Make very sure you do not leave fingerprints or any other smudges on the glass
of the bulb.
 Screw the cover back on.
(2) K 
°F  459.67  .
1.8
For each of the four surfaces, the measurements will lie very close to a straight line, thus
confirming the Stefan-Boltzmann law:
(3) U  I 
U:
I:
P:
A:
T:
T0:
3


P
     T 4  T0 4 .
A
Measured voltage
Intensity of radiation
Radiation power
Area
Temperature
Ambient temperature
:
:
Emissivity
Stefan-Boltzmann constant:
(4)   5.67  10 8
6. Storage, cleaning and disposal

W
.
2
m  K4
Notes:
For an ideal black body  = 1.
A so-called grey body cannot fully absorb all the
radiation falling on its and cannot therefore fully
emit radiation, i.e.  < 1.
In general  is dependent on the wavelength  of
the incident the radiation, i.e.  = ().





Keep the equipment in a clean, dry and
dust-free place.
Before cleaning the equipment, disconnect it
from its power supply.
Do not clean the unit with volatile solvents or
abrasive cleaners.
Use a soft, damp cloth to clean it.
The packaging should be dis-posed of at
local recycling points.
Should you need to
dispose
of
the
equipment itself, never
throw it away in normal
domes-tic waste. Local
regulations for the disposal
of
electrical
equipment will apply.
U / mV
14
12
10
8
6
4
2
0
0
20
40
60
80
100
120
140
160
4
4
180
8
T -T0 / 10 K
Fig. 2:
Voltage U in as a function of T4 – T04 for the matt (black squares), polished (red circles), white (blue
triangles) and black (olive triangles) sides of the Leslie cube.
3B Scientific GmbH ▪ Rudorffweg 8 ▪ 21031 Hamburg ▪ Germany ▪ www.3bscientific.com
Subject to technical amendments
© Copyright 2015 3B Scientific GmbH
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